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Chemistry

Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter 3

Stoichiometry - all with Video Answers

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Chapter Questions

05:18

Problem 1

The following are actual student responses to the question: Why is it necessary to balance chemical equations?
a. The chemicals will not react until you have added the correct mole ratios.
b. The correct products will not be formed unless the right amount of reactants have been added.
c. A certain number of products cannot be formed without a certain number of reactants.
d. The balanced equation tells you how much reactant you need and allows you to predict how much product you’ll make.
e. A mole-to-mole ratio must be established for the reaction to occur as written.
Justify the best choice, and for choices you did not pick, explain what is wrong with them.

Brian Hopper
Brian Hopper
Numerade Educator
01:17

Problem 2

What information do we get from a chemical formula? From a chemical equation?

David Collins
David Collins
Numerade Educator
03:57

Problem 3

True or false? The atom with the largest subscript in a formula is the atom with the largest percent by mass in the compound. If true, explain why with an example. If false, explain why with an example. In either case, provide mathematical support.

Brian Hopper
Brian Hopper
Numerade Educator
05:18

Problem 4

You have a 20.0-g sample of silver metal. You are given 10.0 g of another metal and told that this sample contains twice the number of atoms as the sample of silver metal. Is this possible?

Dominique Jan Tan
Dominique Jan Tan
Numerade Educator
06:17

Problem 5

You are making cookies and are missing a key ingredient—eggs. You have most of the other ingredients needed to make the cookies, except you have only 1.33 cups of butter and no eggs. You note that the recipe calls for two cups of butter and three eggs (plus the other ingredients) to make six dozen cookies. You call a friend and have him bring you some eggs.
a. What number of eggs do you need?
b. If you use all the butter (and get enough eggs), what number of cookies will you make Unfortunately, your friend hangs up before you tell him how many eggs you need. When he arrives, he has a surprise for you—to save time, he has broken them all in a bowl for you. You ask him how many he brought, and he replies, “I can’t remember.” You weigh the eggs and find that they weigh 62.1 g.
Assuming that an average egg weighs 34.21 g,
a. What quantity of butter is needed to react with all the eggs?
b. What number of cookies can you make?
c. Which will you have left over, eggs or butter?
d. What quantity is left over?

Brian Hopper
Brian Hopper
Numerade Educator
05:36

Problem 6

Nitrogen gas $\left(\mathrm{N}_{2}\right)$ and hydrogen gas $\left(\mathrm{H}_{2}\right)$ react to form ammonia gas ( $\mathrm{NH}_{3} ) .$ Consider the mixture of $\mathrm{N}_{2}$ and $\mathrm{H}_{2}$ in $\mathrm{a}$ closed container as illustrated below:
Assuming the reaction goes to completion, draw a representation of the product mixture. Explain how you arrived at this representation.

Kevin Chimex
Kevin Chimex
Numerade Educator
03:36

Problem 7

For the preceding question, which of the following equations best represents the reaction?
a. $6 \mathrm{N}_{2}+6 \mathrm{H}_{2} \longrightarrow 4 \mathrm{NH}_{3}+4 \mathrm{N}_{2}$
b. $\mathrm{N}_{2}+\mathrm{H}_{2} \longrightarrow \mathrm{NH}_{3}$
c. $\mathrm{N}+3 \mathrm{H} \longrightarrow \mathrm{NH}_{3}$
d. $\mathrm{N}_{2}+3 \mathrm{H}_{2} \longrightarrow 2 \mathrm{NH}_{3}$
e. $2 \mathrm{N}_{2}+6 \mathrm{H}_{2} \longrightarrow 4 \mathrm{NH}_{3}$
Justify your choice, and for choices you did not pick, explain what is wrong with them.

Brian Hopper
Brian Hopper
Numerade Educator
03:30

Problem 8

You know that chemical $A$ reacts with chemical $B .$ You react 10.0 g $A$ with 10.0 g $B$ . What information do you need to determine the amount of product that will be produced? Explain.

Kevin Chimex
Kevin Chimex
Numerade Educator
01:41

Problem 9

A new grill has a mass of 30.0 $\mathrm{kg} .$ You put 3.0 $\mathrm{kg}$ of charcoal in the grill. You burn all the charcoal and the grill has a mass of 30.0 $\mathrm{kg}$ . What is the mass of the gases given off? Explain.

Brian Hopper
Brian Hopper
Numerade Educator
03:54

Problem 10

Consider an iron bar on a balance as shown.
As the iron bar rusts, which of the following is true? Explain your answer.
a. The balance will read less than 75.0 $\mathrm{g} .$
b. The balance will read 75.0 $\mathrm{g}$ .
c. The balance will read greater than 75.0 $\mathrm{g}$ .
d. The balance will read greater than 75.0 $\mathrm{g}$ , but if the bar is removed, the rust is scraped off, and the bar replaced, the balance will read 75.0 $\mathrm{g} .$

Christopher Nilsen
Christopher Nilsen
Numerade Educator
02:29

Problem 11

You may have noticed that water sometimes drips from the exhaust of a car as it is running. Is this evidence that there is at least a small amount of water originally present in the gasoline? Explain.

Brian Hopper
Brian Hopper
Numerade Educator
01:01

Problem 12

You react chemical $A$ with chemical $B$ to make one product. It takes 100 of $A$ to react completely with 20 $\mathrm{g}$ of $B$ . What is the mass of the product?
a. less than 10 g
b. between 20 and 100 g
c. between 100 and 120 g
d. exactly 120 g
e. more than 120 g

Kevin Chimex
Kevin Chimex
Numerade Educator
01:54

Problem 13

You react chemical A with chemical B to make one product. It takes 100 g of A to react completely with 20 g of B. What is true about the chemical properties of the product?
a. The properties are more like chemical A.
b. The properties are more like chemical B.
c. The properties are an average of those of chemical A and chemical B.
d. The properties are not necessarily like either chemical A or chemical B.
e. The properties are more like chemical A or more like chemical B, but more information is needed.
Justify your choice, and for choices you did not pick, explain what is wrong with them.

Brian Hopper
Brian Hopper
Numerade Educator
01:20

Problem 14

Is there a difference between a homogeneous mixture of hydrogen and oxygen in a 2:1 mole ratio and a sample of water vapor? Explain.

Kevin Chimex
Kevin Chimex
Numerade Educator
01:07

Problem 15

Chlorine exists mainly as two isotopes, 37 $\mathrm{Cl}$ and $^{35} \mathrm{Cl}$ . Which is more abundant? How do you know?

Brian Hopper
Brian Hopper
Numerade Educator
01:05

Problem 16

The average mass of a carbon atom is 12.011 . Assuming you could pick up one carbon atom, estimate the chance that you would randomly get one with a mass of 12.011 . Support your answer.

Kevin Chimex
Kevin Chimex
Numerade Educator
02:56

Problem 17

Can the subscripts in a chemical formula be fractions? Explain. Can the coefficients in a balanced chemical equation be fractions? Explain. Changing the subscripts of chemicals can balance the equations mathematically. Why is this unacceptable?

Brian Hopper
Brian Hopper
Numerade Educator
03:24

Problem 18

Consider the equation $2 A+B \longrightarrow A_{2} B .$ If you mix 1.0 mole of $A$ with 1.0 mole of $B,$ what amount (moles) of $A_{2} B$ can be produced?

Kevin Chimex
Kevin Chimex
Numerade Educator
03:05

Problem 19

According to the law of conservation of mass, mass cannot be gained or destroyed in a chemical reaction. Why can’t you simply add the masses of two reactants to determine the total mass of product?

Brian Hopper
Brian Hopper
Numerade Educator
01:38

Problem 20

Which of the following pairs of compounds have the same empirical formula?
a. acetylene, $\mathrm{C}_{2} \mathrm{H}_{2},$ and benzene, $\mathrm{C}_{6} \mathrm{H}_{6}$
b. ethane, $\mathrm{C}_{2} \mathrm{H}_{6},$ and butane, $\mathrm{C}_{4} \mathrm{H}_{10}$
c. nitrogen dioxide, $\mathrm{NO}_{2},$ and dinitrogen tetroxide, $\mathrm{N}_{2} \mathrm{O}_{4}$
d. diphenyl ether, $\mathrm{C}_{12} \mathrm{H}_{10} \mathrm{O}$ , and phenol, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}$

Anthony Han
Anthony Han
Numerade Educator
03:00

Problem 21

Atoms of three different elements are represented by $\mathrm{O},$ and $\Delta$ . Which compound is left over when three molecules of O\Delta and three molecules of $\square \square \Delta$ react to form $\mathrm{O} \square \Delta$ and O\Delta\Delta?

Brian Hopper
Brian Hopper
Numerade Educator
02:27

Problem 22

In chemistry, what is meant by the term "mole"? What is the importance of the mole concept?

Kevin Chimex
Kevin Chimex
Numerade Educator
04:12

Problem 23

Which (if any) of the following is(are) true regarding the limiting reactant in a chemical reaction?
a. The limiting reactant has the lowest coefficient in a balanced equation.
b. The limiting reactant is the reactant for which you have the fewest number of moles.
c. The limiting reactant has the lowest ratio of moles available/coefficient in the balanced equation.
d. The limiting reactant has the lowest ratio of coefficient in the balanced equation/moles available.
Justify your choice. For those you did not choose, explain why they are incorrect.

Brian Hopper
Brian Hopper
Numerade Educator
03:51

Problem 24

Consider the equation $3 \mathrm{A}+\mathrm{B} \rightarrow \mathrm{C}+\mathrm{D} .$ You react 4 moles of A with 2 moles of $\mathrm{B}$ . Which of the following is true?
a. The limiting reactant is the one with the higher molar mass.
b. A is the limiting reactant because you need 6 moles of A and have 4 moles.
c. B is the limiting reactant because you have fewer moles of B than A.
d. B is the limiting reactant because three A molecules react with each B molecule.
e. Neither reactant is limiting.
Justify your choice. For those you did not choose, explain why they are incorrect.

Kevin Chimex
Kevin Chimex
Numerade Educator
03:50

Problem 25

The atomic masses in the periodic table are relative masses and average masses. Explain.

Brian Hopper
Brian Hopper
Numerade Educator
04:08

Problem 26

Avogadro’s number, molar mass, and the chemical formula of a compound are three useful conversion factors. What unit conversions can be accomplished using these conversion factors?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:37

Problem 27

If you had a mole of U.S. dollar bills and equally distributed the money to all of the people of the world, how rich would every person be? Assume a world population of 7 billion.

Brian Hopper
Brian Hopper
Numerade Educator
01:25

Problem 28

Describe 1 mole of $\mathrm{CO}_{2}$ in as many ways as you can.

Kevin Chimex
Kevin Chimex
Numerade Educator
01:30

Problem 29

Which of the following compounds have the same empirical formulas?

Brian Hopper
Brian Hopper
Numerade Educator
06:26

Problem 30

What is the difference between the molar mass and the empirical formula mass of a compound? When are these masses the same, and when are they different? When different, how is the molar mass related to the empirical formula mass?

Kevin Chimex
Kevin Chimex
Numerade Educator
03:48

Problem 31

How is the mass percent of elements in a compound different for a 1.0-g sample versus a 100.-g sample versus a 1-mole sample of the compound?

Brian Hopper
Brian Hopper
Numerade Educator
02:06

Problem 32

A balanced chemical equation contains a large amount of information. What information is given in a balanced equation?

Kevin Chimex
Kevin Chimex
Numerade Educator
03:09

Problem 33

The reaction of an element X with element Y is represented in the following diagram. Which of the equations best describes this reaction?
a. $3 \mathrm{X}+8 \mathrm{Y} \rightarrow \mathrm{X}_{3} \mathrm{Y}_{8}$
b. $3 \mathrm{X}+6 \mathrm{Y} \rightarrow \mathrm{X}_{3} \mathrm{Y}_{6}$
c. $\mathrm{X}+2 \mathrm{Y} \rightarrow \mathrm{XY}_{2}$
d. $3 \mathrm{X}+8 \mathrm{Y} \rightarrow 3 \mathrm{XY}_{2}+2 \mathrm{Y}$

Brian Hopper
Brian Hopper
Numerade Educator
03:20

Problem 34

Hydrogen gas and oxygen gas react to form water, and this reaction can be depicted as follows: Explain why this equation is not balanced, and draw a picture of the balanced equation.

Kevin Chimex
Kevin Chimex
Numerade Educator
02:24

Problem 35

What is the theoretical yield for a reaction, and how does this quantity depend on the limiting reactant?

Brian Hopper
Brian Hopper
Numerade Educator
06:31

Problem 36

What does it mean to say a reactant is present “in excess” in a process? Can the limiting reactant be present in excess? Does the presence of an excess of a reactant affect the mass of products expected for a reaction?

Kevin Chimex
Kevin Chimex
Numerade Educator
07:53

Problem 37

Consider the following generic reaction:
$$
\mathrm{A}_{2} \mathrm{B}_{2}+2 \mathrm{C} \longrightarrow 2 \mathrm{CB}+2 \mathrm{A}
$$
What steps and information are necessary to perform the following determinations assuming that $1.00 \times 10^{4}$ molecules of $\mathrm{A}_{2} \mathrm{B}_{2}$ are reacted with excess $\mathrm{C}$ ?
a. mass of CB produced
b. atoms of A produced
c. moles of C reacted
d. percent yield of CB

Brian Hopper
Brian Hopper
Numerade Educator
03:27

Problem 38

Consider the following generic reaction:
$$
\mathrm{Y}_{2}+2 \mathrm{XY} \longrightarrow 2 \mathrm{XY}_{2}
$$
In a limiting reactant problem, a certain quantity of each reactant is given and you are usually asked to calculate the mass of product formed. If 10.0 $\mathrm{g}$ of $\mathrm{Y}_{2}$ is reacted with 10.0 $\mathrm{g}$ of $\mathrm{XY}$ , outline two methods you could use to determine which reactant is limiting (runs out first) and thus determines the mass of product formed.

Kevin Chimex
Kevin Chimex
Numerade Educator
02:57

Problem 39

An element consists of 1.40$\%$ of an isotope with mass 203.973 u, 24.10$\%$ of an isotope with mass 205.9745 u, 22.10$\%$ of an isotope with mass 206.9759 u, and 52.40$\%$ of an isotope with mass 207.9766 u. Calculate the average atomic mass, and identify the element.

Brian Hopper
Brian Hopper
Numerade Educator
03:17

Problem 40

An element "X" has five major isotopes, which are listed below along with their abundances. What is the element?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:16

Problem 41

The element rhenium (Re) has two naturally occurring isotopes, $^{185}$ $\mathrm{Re}$ and $^{187}$ $\mathrm{Re},$ with an average atomic mass of 186.207 u. Rhenium is 62.60$\%$ of Re, and the atomic mass of $^{187}$Re is 186.956 u. Calculate the mass of $^{185}$Re.

David Collins
David Collins
Numerade Educator
04:26

Problem 42

Assume silicon has three major isotopes in nature as shown in the table below. Fill in the missing information.

Rabia Shuaib
Rabia Shuaib
Numerade Educator
07:00

Problem 43

The element europium exists in nature as two isotopes: 151 $\mathrm{Eu}$ has a mass of 150.9196 $\mathrm{u}$ and $^{153} \mathrm{Eu}$ has a mass of 152.9209 $\mathrm{u}$ . The average atomic mass of europium is 151.96 u. Calculate the relative abundance of the two europium isotopes.

Brian Hopper
Brian Hopper
Numerade Educator
01:49

Problem 44

The element silver (Ag) has two naturally occurring isotopes: 109 $\mathrm{Ag}$ and $^{107} \mathrm{Ag}$ with a mass of 106.905 $\mathrm{u} .$ Silver consists of 51.82$\%$ of Ag and has an average atomic mass of 107.868 u. Calculate the mass of $^{109} \mathrm{Ag}$ .

Ronald Prasad
Ronald Prasad
Numerade Educator
01:54

Problem 45

The mass spectrum of bromine (Br_ $_{2} )$ consists of three peaks with the following characteristics: How do you interpret these data?

Brian Hopper
Brian Hopper
Numerade Educator
View

Problem 46

The stable isotopes of iron are $^{54} \mathrm{Fe},^{56} \mathrm{Fe},^{57} \mathrm{Fe},$ and $^{58} \mathrm{Fe}$ . The mass spectrum of iron looks like the following:
Use the data on the mass spectrum to estimate the average atomic mass of iron, and compare it to the value given in the table inside the front cover of this book.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
04:35

Problem 47

Calculate the mass of 500 . atoms of iron (Fe).

Brian Hopper
Brian Hopper
Numerade Educator
03:09

Problem 48

What number of Fe atoms and what amount (moles) of Fe atoms are in 500.0 g of iron?

Christopher Nilsen
Christopher Nilsen
Numerade Educator
03:38

Problem 49

Diamond is a natural form of pure carbon. What number of atoms of carbon are in a 1.00 -carat diamond $(1.00 \text { carat }=$ 0.200 $\mathrm{g}$ )?

Brian Hopper
Brian Hopper
Numerade Educator
01:45

Problem 50

Chromium (Cr) is a metal that is added to steel to improve its resistance to corrosion. Calculate the number of moles in a sample of chromium containing $5.00 \times 10^{20}$ atoms and the mass of the sample.

Anand Jangid
Anand Jangid
Numerade Educator
04:54

Problem 51

Selective serotonin reuptake inhibitors (SSRIs) are a common prescribed antidepressant. SSRIs block the reabsorption of the neurotransmitter serotonin in the brain. Changing the balance of serotonin helps brain cells send and receive chemical messages, which in turn boosts mood. Two SSRI medications are Prozac (fluoxetine, $\mathrm{C}_{17} \mathrm{H}_{18} \mathrm{F}_{3} \mathrm{NO} )$ and Zoloft
(sertraline, $\mathrm{C}_{17} \mathrm{H}_{17} \mathrm{Cl}_{2} \mathrm{N} )$ . Determine the molar masses of Prozac and Zoloft.

Brian Hopper
Brian Hopper
Numerade Educator
03:25

Problem 52

The Freons are a class of compounds containing carbon, chlorine, and fluorine. While they have many valuable uses, they have been shown to be responsible for depletion of the ozone in the upper atmosphere. In 1991 , two replacement compounds for Freons went into production: $\mathrm{HFC}-134 \mathrm{a}\left(\mathrm{CH}_{2} \mathrm{FCF}_{3}\right)$ and $\mathrm{HCFC}-124\left(\mathrm{CHCIFCF}_{3}\right)$ Calculate the molar masses of these two compounds.

Jennifer Hudspeth
Jennifer Hudspeth
Numerade Educator
02:44

Problem 53

Calculate the molar mass of the following substances.

Brian Hopper
Brian Hopper
Numerade Educator
04:57

Problem 54

Calculate the molar mass of the following substances.

Jennifer Hudspeth
Jennifer Hudspeth
Numerade Educator
02:58

Problem 55

What amount (moles) of compound is present in 1.00 g of each of the compounds in Exercise 53?

Brian Hopper
Brian Hopper
Numerade Educator
01:26

Problem 56

What amount (moles) of compound is present in 1.00 g of each of the compounds in Exercise 54?

David Collins
David Collins
Numerade Educator
02:48

Problem 57

What mass of compound is present in 5.00 moles of each of the compounds in Exercise 53?

Brian Hopper
Brian Hopper
Numerade Educator
02:11

Problem 58

What mass of compound is present in 5.00 moles of each of the compounds in Exercise 54?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:06

Problem 59

What mass of nitrogen is present in 5.00 moles of each of the compounds in Exercise 53?

Brian Hopper
Brian Hopper
Numerade Educator
04:25

Problem 60

What mass of phosphorus is present in 5.00 moles of each of the compounds in Exercise 54?

Kevin Chimex
Kevin Chimex
Numerade Educator
01:43

Problem 61

What number of molecules (or formula units) are present in 1.00 g of each of the compounds in Exercise 53?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:29

Problem 62

What number of molecules (or formula units) are present in 1.00 g of each of the compounds in Exercise 54?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:00

Problem 63

What number of atoms of nitrogen are present in 1.00 g of each of the compounds in Exercise 53?

Ronald Prasad
Ronald Prasad
Numerade Educator
08:02

Problem 64

What number of atoms of phosphorus are present in 1.00 g of each of the compounds in Exercise 54?

Jennifer Hudspeth
Jennifer Hudspeth
Numerade Educator
00:59

Problem 65

Freon- 12$\left(\mathrm{CCl}_{2} \mathrm{F}_{2}\right)$ is used as a refrigerant in air conditioners and as a propellant in aerosol cans. Calculate the number of molecules of Freon-12 5.56 $\mathrm{mg}$ of Freon-12. What is the mass of chlorine in 5.56 $\mathrm{mg}$ of Freon-12?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:55

Problem 66

Prevacid is used to treat gastroesophageal reflux disease $(\mathrm{GERD})$ . The chemical formula of Prevacid is $\mathrm{C}_{16} \mathrm{H}_{14} \mathrm{F}_{3} \mathrm{N}_{3} \mathrm{O}_{2} \mathrm{S}$ .
a. What is the molar mass of Prevacid?
b. What mass of fluorine is in 0.75 mol of Prevacid?
c. What number of carbon atoms is in 0.75 mol of Prevacid?
d. What is the mass of $4.25 \times 10^{21}$ molecules of Prevacid?

Cheryl Glor
Cheryl Glor
Numerade Educator
01:30

Problem 67

What amount (moles) is represented by each of these samples?
a. 150.0 g Fe_ $\mathrm{O}_{3}$
b. 10.0 $\mathrm{mg} \mathrm{NO}_{2}$
c. $1.5 \times 10^{16}$ molecules of $\mathrm{BF}_{3}$

Ronald Prasad
Ronald Prasad
Numerade Educator
02:57

Problem 68

Consider the following space-filling models for dry ice, ethanol, and caffeine:
What amount (moles) is represented by each of the following samples?
a. 1.50 g of dry ice
b. $2.72 \times 10^{21}$ molecules of ethanol
c. 20.0 mg of caffeine

Ronald Prasad
Ronald Prasad
Numerade Educator
03:10

Problem 69

What number of atoms of nitrogen are present in 5.00 g of each of the following?
$\begin{array}{ll}{\text { a. glycine, } \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{O}_{2} \mathrm{N}} & {\text { c. calcium nitrate }} \\ {\text { b. magnesium nitride }} & {\text { d. dinitrogen tetroxide }}\end{array}$

Ronald Prasad
Ronald Prasad
Numerade Educator
00:29

Problem 70

Complete the following table.

Tianyu Li
Tianyu Li
Numerade Educator
01:50

Problem 71

Ascorbic acid, or vitamin $\mathrm{C}\left(\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{6}\right),$ is an essential vitamin. It cannot be stored by the body and must be present in the diet. What is the molar mass of ascorbic acid? Vitamin C tablets are taken as a dietary supplement. If a typical tablet contains
500.0 $\mathrm{mg}$ of vitamin $\mathrm{C}$ , what amount (moles) of vitamin C is contained in 10 tablets? What number of vitamin C molecules is in eight tablets?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:39

Problem 72

The molecular formula of acetylsalicylic acid (aspirin), one of the most commonly used pain relievers, is $\mathrm{C}_{9} \mathrm{H}_{8} \mathrm{O}_{4} .$
a. Calculate the molar mass of aspirin.
b. A typical aspirin tablet contains 500 . mg $\mathrm{C}_{9} \mathrm{H}_{8} \mathrm{O}_{4}$ . What amount (moles) of $\mathrm{C}_{9} \mathrm{H}_{8} \mathrm{O}_{4}$ molecules and what number of molecules of acetylsalicylic acid are in a 500 -mg tablet?

Kevin Chimex
Kevin Chimex
Numerade Educator
03:35

Problem 73

Chloral hydrate $\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{Cl}_{3} \mathrm{O}_{2}\right)$ is a drug formerly used as a sedative and hypnotic. It is the compound used to make "Mickey Finns" in detective stories.
a. Calculate the molar mass of chloral hydrate.
b. What amount (moles) of $\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{Cl}_{3} \mathrm{O}_{2}$ molecules are in 500.0 $\mathrm{g}$ chloral hydrate?
c. What is the mass in grams of $2.0 \times 10^{-2}$ mole of chloral hydrate?
d. What number of chlorine atoms are in 5.0 g chloral hydrate?
e. What mass of chloral hydrate would contain 1.0 g Cl?
f. What is the mass of exactly 500 molecules of chloral hydrate?

Ronald Prasad
Ronald Prasad
Numerade Educator
12:28

Problem 74

Dimethylnitrosamine, $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{N}_{2} \mathrm{O}$ is a carcinogenic (cancer causing) substance that may be formed in foods, beverages, or gastric juices from the reaction of nitrite ion (used as a food preservative) with other substances.
a. What is the molar mass of dimethylnitrosamine?
b. How many moles of $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{N}_{2} \mathrm{O}$ molecules are present in 250 mg dimethylnitrosamine?
c. What is the mass of 0.050 mole of dimethylnitrosamine?
d. How many atoms of hydrogen are in 1.0 mole of dimethylnitrosamine?
e. What is the mass of $1.0 \times 10^{6}$ molecules of dimethylnitrosamine?
f. What is the mass in grams of one molecule of dimethylnitrosamine?

Kevin Chimex
Kevin Chimex
Numerade Educator
04:03

Problem 75

Calculate the percent composition by mass of the following compounds that are important starting materials for synthetic polymers:
a. $\mathrm{C}_{3} \mathrm{H}_{4} \mathrm{O}_{2}$ (acrylic acid, from which acrylic plastics are made)
b. $\mathrm{C}_{4} \mathrm{H}_{6} \mathrm{O}_{2}$ (methyl acrylate, from which Plexiglas is made)
c. $\mathrm{C}_{3} \mathrm{H}_{3} \mathrm{N}$ (acrylonitrile, from which Orlon is made)

Ronald Prasad
Ronald Prasad
Numerade Educator
04:12

Problem 76

In 1987 the first substance to act as a superconductor at a temperature above that of liquid nitrogen $(77 \mathrm{K})$ was discovered. The approximate formula of this substance is $\mathrm{YBa}_{2} \mathrm{Cu}_{3} \mathrm{O}_{7}$ Calculate the percent composition by mass of this material.

Kevin Chimex
Kevin Chimex
Numerade Educator
01:56

Problem 77

The percent by mass of nitrogen for a compound is found to be 46.7$\%$ . Which of the following could be this species?

Ronald Prasad
Ronald Prasad
Numerade Educator
07:02

Problem 78

Arrange the following substances in order of increasing mass percent of carbon.
a. caffeine, $\mathrm{C}_{8} \mathrm{H}_{10} \mathrm{N}_{4} \mathrm{O}_{2}$
b. sucrose, $\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}$
c. ethanol, $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}$

Kevin Chimex
Kevin Chimex
Numerade Educator
01:00

Problem 79

Fungal laccase, a blue protein found in wood-rotting fungi, is 0.390$\% \mathrm{Cu}$ by mass. If a fungal laccase molecule contains four copper atoms, what is the molar mass of fungal laccase?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:55

Problem 80

Hemoglobin is the protein that transports oxygen in mammals. Hemoglobin is 0.347$\%$ Fe by mass, and each hemoglobin molecule contains four iron atoms. Calculate the molar mass of hemoglobin.

Kevin Chimex
Kevin Chimex
Numerade Educator
03:03

Problem 81

Express the composition of each of the following compounds as the mass percents of its elements.
a. formaldehyde, $\mathrm{CH}_{2} \mathrm{O}$
b. glucose, $\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}$
c. acetic acid, $\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:21

Problem 82

Considering your answer to Exercise $81,$ which type of formula, empirical or molecular, can be obtained from elemental analysis that gives percent composition?

Kevin Chimex
Kevin Chimex
Numerade Educator
00:49

Problem 83

Give the empirical formula for each of the compounds represented below.

Ronald Prasad
Ronald Prasad
Numerade Educator
04:59

Problem 84

Determine the molecular formulas to which the following empirical formulas and molar masses pertain.
a. $\operatorname{SNH}(188.35 \mathrm{g} / \mathrm{mol})$
b. $\mathrm{NPCl}_{2}(347.64 \mathrm{g} / \mathrm{mol})$
c. $\operatorname{CoC}_{4} \mathrm{O}_{4}(341.94 \mathrm{g} / \mathrm{mol})$
d. $\mathrm{SN}(184.32 \mathrm{g} / \mathrm{mol})$

Christopher Nilsen
Christopher Nilsen
Numerade Educator
02:13

Problem 85

A compound that contains only carbon, hydrogen, and oxygen is 48.64$\% \mathrm{C}$ and 8.16$\% \mathrm{H}$ by mass. What is the empirical formula of this substance?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:30

Problem 86

The most common form of nylon (nylon-6) is 63.68$\%$ carbon, 12.38$\%$ nitrogen, 9.80$\%$ hydrogen, and 14.14$\%$ oxygen. Calculate the empirical formula for nylon-6.

Kevin Chimex
Kevin Chimex
Numerade Educator
03:59

Problem 87

There are two binary compounds of mercury and oxygen. Heating either of them results in the decomposition of the compound, with oxygen gas escaping into the atmosphere while leaving a residue of pure mercury. Heating 0.6498 g of one of the compounds leaves a residue of 0.6018 g. Heating 0.4172 g of the other compound results in a mass loss of 0.016 g. Determine the empirical formula of each compound.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:21

Problem 88

A sample of urea contains $1.121 \mathrm{g} \mathrm{N}, 0.161 \mathrm{g} \mathrm{H}, 0.480 \mathrm{g} \mathrm{C}$ and 0.640 $\mathrm{g}$ O. What is the empirical formula of urea?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:27

Problem 89

A compound containing only sulfur and nitrogen is 69.6$\% \mathrm{S}$ by mass; the molar mass is 184 $\mathrm{g} / \mathrm{mol}$ . What are the empirical and molecular formulas of the compound?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:43

Problem 90

Determine the molecular formula of a compound that contains $26.7 \% \mathrm{P}, 12.1 \% \mathrm{N},$ and $61.2 \% \mathrm{Cl},$ and has a molar mass of 580 $\mathrm{g} / \mathrm{mol}$

Kevin Chimex
Kevin Chimex
Numerade Educator
02:33

Problem 91

A compound contains 47.08$\%$ carbon, 6.59$\%$ hydrogen, and 46.33$\%$ chlorine by mass; the molar mass of the compound is 153 g/mol. What are the empirical and molecular formulas of the compound?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:39

Problem 92

Maleic acid is an organic compound composed of $41.39 \% \mathrm{C},$ 3.47$\% \mathrm{H}$ , and the rest oxygen. If 0.129 mole of maleic acid has a mass of 15.0 $\mathrm{g}$ , what are the empirical and molecular formulas of maleic acid?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:56

Problem 93

One of the components that make up common table sugar is fructose, a compound that contains only carbon, hydrogen, and oxygen. Complete combustion of 1.50 $\mathrm{g}$ of fructose produced 2.20 $\mathrm{g}$ of carbon dioxide and 0.900 $\mathrm{g}$ of water. What is the empirical formula of fructose?

Ronald Prasad
Ronald Prasad
Numerade Educator
18:15

Problem 94

A compound contains only $\mathrm{C}, \mathrm{H},$ and $\mathrm{N}$ . Combustion of 35.0 $\mathrm{mg}$ of the compound produces 33.5 $\mathrm{mg} \mathrm{CO}_{2}$ and 41.1 $\mathrm{mg}$ $\mathrm{H}_{2} \mathrm{O}$ . What is the empirical formula of the compound?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:59

Problem 95

Cumene is a compound containing only carbon and hydrogen that is used in the production of acetone and phenol in the chemical industry. Combustion of 47.6 $\mathrm{mg}$ cumene produces some $\mathrm{CO}_{2}$ and 42.8 $\mathrm{mg}$ water. The molar mass of cumene is between 115 and 125 $\mathrm{g} / \mathrm{mol}$ . Determine the empirical and molecular formulas.

Lottie Adams
Lottie Adams
Numerade Educator
08:16

Problem 96

A compound contains only carbon, hydrogen, and oxygen. Combustion of 10.68 $\mathrm{mg}$ of the compound yields 16.01 $\mathrm{mg}$ $\mathrm{CO}_{2}$ and 4.37 $\mathrm{mg} \mathrm{H}_{2} \mathrm{O}$ . The molar mass of the compound is 176.1 $\mathrm{g} / \mathrm{mol} .$ What are the empirical and molecular formulas of the compound?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:07

Problem 97

Give the balanced equation for each of the following chemical reactions:
a. Glucose $\left(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\right)$ reacts with oxygen gas to produce gaseous carbon dioxide and water vapor.
b. Solid iron(III) sulfide reacts with gaseous hydrogen chloride to form solid iron((III) chloride and hydrogen sulfide gas.
c. Carbon disulfide liquid reacts with ammonia gas to produce hydrogen sulfide gas and solid ammonium thiocyanate $\left(\mathrm{NH}_{4} \mathrm{SCN}\right)$

Ronald Prasad
Ronald Prasad
Numerade Educator
02:22

Problem 98

Give the balanced equation for each of the following.
a. The combustion of ethanol $\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)$ forms carbon dioxide and water vapor. A combustion reaction refers to a reaction of a substance with oxygen gas.
b. Aqueous solutions of lead(Il) nitrate and sodium phosphate are mixed, resulting in the precipitate formation of lead(II) phosphate with aqueous sodium nitrate as the other product.
c. Solid zinc reacts with aqueous HCl to form aqueous zinc chloride and hydrogen gas.
d. Aqueous strontium hydroxide reacts with aqueous hydrobromic acid to produce water and aqueous strontium bromide.

Ronald Prasad
Ronald Prasad
Numerade Educator
00:26

Problem 99

A common demonstration in chemistry courses involves adding a tiny speck of manganese(IV) oxide to a concentrated hydrogen peroxide $\left(\mathrm{H}_{2} \mathrm{O}_{2}\right)$ solution. Hydrogen peroxide decomposes quite spectacularly under these conditions to produce oxygen gas and steam (water vapor). Manganese(IV) oxide is a catalyst for the decomposition of hydrogen peroxide and is not consumed in the reaction. Write the balanced equation for the decomposition reaction of hydrogen peroxide.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:07

Problem 100

Iron oxide ores, commonly a mixture of FeO and $\mathrm{Fe}_{2} \mathrm{O}_{3},$ are given the general formula $\mathrm{Fe}_{3} \mathrm{O}_{4}$ . They yield elemental iron when heated to a very high temperature with either carbon monoxide or elemental hydrogen. Balance the following equations for these processes:
$$
\begin{array}{c}{\mathrm{Fe}_{3} \mathrm{O}_{4}(s)+\mathrm{H}_{2}(g) \longrightarrow \mathrm{Fe}(s)+\mathrm{H}_{2} \mathrm{O}(g)} \\ {\mathrm{Fe}_{3} \mathrm{O}_{4}(s)+\mathrm{CO}(g) \longrightarrow \mathrm{Fe}(s)+\mathrm{CO}_{2}(g)}\end{array}
$$

Kevin Chimex
Kevin Chimex
Numerade Educator
01:55

Problem 101

Balance the following equations:
a. $\mathrm{Ca}(\mathrm{OH})_{2}(a q)+\mathrm{H}_{3} \mathrm{PO}_{4}(a q) \rightarrow \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}(s)$
b. $\mathrm{Al}(\mathrm{OH})_{3}(s)+\mathrm{HCl}(a q) \rightarrow \mathrm{AlCl}_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l)$
c. $\mathrm{AgNO}_{3}(a q)+\mathrm{H}_{2} \mathrm{SO}_{4}(a q) \rightarrow \mathrm{Ag}_{2} \mathrm{SO}_{4}(s)+\mathrm{HNO}_{3}(a q)$

Ronald Prasad
Ronald Prasad
Numerade Educator
08:09

Problem 102

Balance each of the following chemical equations.
a. $\mathrm{KO}_{2}(s)+\mathrm{H}_{2} \mathrm{O}(l) \rightarrow \mathrm{KOH}(a q)+\mathrm{O}_{2}(g)+\mathrm{H}_{2} \mathrm{O}_{2}(a q)$
b. $\mathrm{Fe}_{2} \mathrm{O}_{3}(s)+\mathrm{HNO}_{3}(a q) \rightarrow \mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l)$
c. $\mathrm{NH}_{3}(g)+\mathrm{O}_{2}(g) \rightarrow \mathrm{NO}(g)+\mathrm{H}_{2} \mathrm{O}(g)$
d. $\mathrm{PCl}_{5}(l)+\mathrm{H}_{2} \mathrm{O}(l) \rightarrow \mathrm{H}_{3} \mathrm{PO}_{4}(a q)+\mathrm{HCl}(g)$
e. $\mathrm{CaO}(s)+\mathrm{C}(s) \rightarrow \mathrm{CaC}_{2}(s)+\mathrm{CO}_{2}(g)$
f. $\operatorname{MoS}_{2}(s)+\mathrm{O}_{2}(g) \rightarrow \mathrm{MoO}_{3}(s)+\mathrm{SO}_{2}(g)$
g. $\mathrm{FeCO}_{3}(s)+\mathrm{H}_{2} \mathrm{CO}_{3}(a q) \rightarrow \mathrm{Fe}\left(\mathrm{HCO}_{3}\right)_{2}(a q)$

Kevin Chimex
Kevin Chimex
Numerade Educator
02:05

Problem 103

Balance the following equations representing combustion reactions:
c. $C_{12} \mathrm{H}_{22} \mathrm{O}_{11}(s)+\mathrm{O}_{2}(g) \rightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)$
d. Fe $(s)+\mathrm{O}_{2}(g) \rightarrow \mathrm{Fe}_{2} \mathrm{O}_{3}(s)$
e. $\mathrm{FeO}(s)+\mathrm{O}_{2}(g) \rightarrow \mathrm{Fe}_{2} \mathrm{O}_{3}(s)$

Ronald Prasad
Ronald Prasad
Numerade Educator
05:11

Problem 104

Balance the following equations:
a. $\operatorname{Cr}(s)+\mathrm{S}_{8}(s) \rightarrow \mathrm{Cr}_{2} \mathrm{S}_{3}(s)$
b. $\operatorname{NaHCO}_{3}(s) \stackrel{\mathrm{Heat}}{\longrightarrow}$ $\mathrm{Na}_{2} \mathrm{CO}_{3}(s)+\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)$
c. $\quad \mathrm{KClO}_{3}(s) \stackrel{\mathrm{Heat}}{\longrightarrow}$ $\mathrm{KCl}(s)+\mathrm{O}_{2}(g)$
d. $\operatorname{Eu}(s)+\mathrm{HF}(g) \rightarrow \operatorname{EuF}_{3}(s)+\mathrm{H}_{2}(g)$

Kevin Chimex
Kevin Chimex
Numerade Educator
02:16

Problem 105

Silicon is produced for the chemical and electronics industries by the following reactions. Give the balanced equation for each reaction.
a. $\mathrm{SiO}_{2}(s)+\mathrm{C}(s)$ $\frac{\text { Electric }}{\text { are furnace }}$ $\mathrm{Si}(s)+\mathrm{CO}(g)$
b. Liquid silicon tetrachloride is reacted with very pure solid magnesium, producing solid silicon and solid magnesium chloride.
c. $\mathrm{Na}_{2} \mathrm{SiF}_{6}(s)+\mathrm{Na}(s) \rightarrow \mathrm{Si}(s)+\mathrm{NaF}(s)$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:26

Problem 106

Glass is a mixture of several compounds, but a major constituent of most glass is calcium silicate, $\mathrm{CaSiO}_{3}$ . Glass can be etched by treatment with hydrofluoric acid; HF attacks the calcium silicate of the glass, producing gaseous and water-soluble products (which can be removed by washing the glass). For example, the volumetric glassware in chemistry laboratories is often graduated by using this process. Balance the following equation for the reaction of hydrofluoric acid with calcium silicate.
$$
\mathrm{CaSiO}_{3}(s)+\mathrm{HF}(a q) \longrightarrow \mathrm{CaF}_{2}(a q)+\mathrm{SiF}_{4}(g)+\mathrm{H}_{2} \mathrm{O}(l)
$$

Kevin Chimex
Kevin Chimex
Numerade Educator
00:57

Problem 107

Phosphorus occurs naturally in the form of fluorapatite, $\mathrm{CaF}_{2} \cdot 3 \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2} .$ The dot indicates 1 part $\mathrm{CaF}_{2}$ to 3 parts $\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2} .$ This mineral is reacted with an aqueous solution of $\mathrm{H}_{2} \mathrm{SO}_{4}$ in the preparation of a fertilizer. The products are phosphoric acid, hydrogen fluoride, and gypsum, CaSO_ $_{4} \cdot 2 \mathrm{H}_{2} \mathrm{O}$ . Write the balanced equation describing this process.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:49

Problem 108

The sugar sucrose, which is present in many fruits and vegetables, reacts in the presence of certain yeast enzymes to produce ethanol and carbon dioxide gas. Balance the following equation for this reaction of sucrose.
$$
\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}(a q)+\mathrm{H}_{2} \mathrm{O}(l) \rightarrow \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}(a q)+\mathrm{CO}_{2}(g)
$$

Kevin Chimex
Kevin Chimex
Numerade Educator
03:41

Problem 109

Over the years, the thermite reaction has been used for welding railroad rails, in incendiary bombs, and to ignite solid-fuel rocket motors. The reaction is
$$
\mathrm{Fe}_{2} \mathrm{O}_{3}(s)+2 \mathrm{Al}(s) \longrightarrow 2 \mathrm{Fe}(l)+\mathrm{Al}_{2} \mathrm{O}_{3}(s)
$$
What masses of iron(III) oxide and aluminum must be used to produce 15.0 $\mathrm{g}$ iron? What is the maximum mass of aluminum oxide that could be produced?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:01

Problem 110

The reaction between potassium chlorate and red phosphorus takes place when you strike a match on a matchbox. If you were to react 52.9 g of potassium chlorate $\left(\mathrm{KClO}_{3}\right)$ with excess red phosphorus, what mass of tetraphosphorus decaoxide $\left(\mathrm{P}_{4} \mathrm{O}_{10}\right)$ could be produced?
$\mathrm{KClO}_{3}(s)+\mathrm{P}_{4}(s) \longrightarrow \mathrm{P}_{4} \mathrm{O}_{10}(s)+\mathrm{KCl}(s) \quad$ (unbalanced)

Christopher Nilsen
Christopher Nilsen
Numerade Educator
01:11

Problem 111

The reusable booster rockets of the U.S. space shuttle employ a mixture of aluminum and ammonium perchlorate for fuel. A possible equation for this reaction is
$$
3 \mathrm{Al}(s)+3 \mathrm{NH}_{4} \mathrm{ClO}_{4}(s) \longrightarrow
$$
$$
\mathrm{Al}_{2} \mathrm{O}_{3}(s)+\mathrm{AlCl}_{3}(s)+3 \mathrm{NO}(g)+6 \mathrm{H}_{2} \mathrm{O}(g)
$$
What mass of $\mathrm{NH}_{4} \mathrm{ClO}_{4}$ should be used in the fuel mixture for every kilogram of Al?

Ronald Prasad
Ronald Prasad
Numerade Educator
06:04

Problem 112

One of relatively few reactions that takes place directly between two solids at room temperature is
$$
\mathrm{Ba}(\mathrm{OH})_{2} \cdot 8 \mathrm{H}_{2} \mathrm{O}(s)+\mathrm{NH}_{4} \mathrm{SCN}(s) \longrightarrow
$$
$$
\mathrm{Ba}(\mathrm{SCN})_{2}(s)+\mathrm{H}_{2} \mathrm{O}(l)+\mathrm{NH}_{3}(g)
$$
In this equation, the $\cdot 8 \mathrm{H}_{2} \mathrm{O}$ in $\mathrm{Ba}(\mathrm{OH})_{2} \cdot 8 \mathrm{H}_{2} \mathrm{O}$ indicates the presence of eight water molecules. This compound is called barium hydroxide octahydrate.
a. Balance the equation.
b. What mass of ammonium thiocyanate (NH_sCN) must be used if it is to react completely with 6.5 g barium hydroxide octahydrate?

Kevin Chimex
Kevin Chimex
Numerade Educator
01:34

Problem 113

The compound cisplatin, $\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2},$ has been studied as an antitumor agent. Cisplatin is synthesized as follows:
$$
\mathrm{K}_{2} \mathrm{PtCl}_{4}(a q)+2 \mathrm{NH}_{3}(a q) \rightarrow \operatorname{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}(s)+2 \mathrm{KCl}(a q)
$$
What mass of cisplatin can be produced from $100 .$ g of $\mathrm{K}_{2} \mathrm{PtCl}_{4}$ and sufficient $\mathrm{NH}_{3} ?$

Ronald Prasad
Ronald Prasad
Numerade Educator
07:46

Problem 114

a. Write the balanced equation for the combustion of isooctane $\left(\mathrm{C}_{8} \mathrm{H}_{18}\right)$ to produce water vapor and carbon dioxide gas.
b. Assuming gasoline is $100 . \%$ isooctane, with a density of 0.692 $\mathrm{g} / \mathrm{mL}$ , what is the theoretical yield of carbon dioxide produced by the combustion of $1.2 \times 10^{10}$ gal of
gasoline (the approximate annual consumption of gasoline in the United States)?

Jennifer Hudspeth
Jennifer Hudspeth
Numerade Educator
02:54

Problem 115

Elixirs such as Alka-Seltzer use the reaction of sodium bicarbonate with citric acid in aqueous solution to produce a fizz:
$$
3 \mathrm{NaHCO}_{3}(a q)+\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{7}(a q) \longrightarrow
$$
$$
3 \mathrm{CO}_{2}(g)+3 \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{Na}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(a q)
$$
a. What mass of $\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{7}$ should be used for every $1.0 \times 10^{2} \mathrm{mg} \mathrm{NaHCO}_{3} ?$
b. What mass of $\mathrm{CO}_{2}(g)$ could be produced from such a mixture?

Ronald Prasad
Ronald Prasad
Numerade Educator
08:21

Problem 116

Aspirin $\left(\mathrm{C}_{9} \mathrm{H}_{8} \mathrm{O}_{4}\right)$ is synthesized by reacting salicylic acid $\left(\mathrm{C}_{7} \mathrm{H}_{6} \mathrm{O}_{3}\right)$ with acetic anhydride $\left(\mathrm{C}_{4} \mathrm{H}_{6} \mathrm{O}_{3}\right) .$ The balanced equation is
$$
\mathrm{C}_{7} \mathrm{H}_{6} \mathrm{O}_{3}+\mathrm{C}_{4} \mathrm{H}_{6} \mathrm{O}_{3} \longrightarrow \mathrm{C}_{9} \mathrm{H}_{8} \mathrm{O}_{4}+\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}
$$
a. What mass of acetic anhydride is needed to completely consume $1.00 \times 10^{2}$ g salicylic acid?
b. What is the maximum mass of aspirin (the theoretical yield) that could be produced in this reaction?

Kevin Chimex
Kevin Chimex
Numerade Educator
03:26

Problem 117

Bacterial digestion is an economical method of sewage treatment. The reaction
$5 \mathrm{CO}_{2}(g)+55 \mathrm{NH}_{4}+(a q)+76 \mathrm{O}_{2}(g) \frac{\text { bacterta }}{52 \mathrm{H}_{2} \mathrm{O}(l)}+109 \mathrm{H}^{+}(a q)$ $\mathrm{C}_{5} \mathrm{H}_{7} \mathrm{O}_{2} \mathrm{N}(s)+54 \mathrm{NO}_{2}^{-}(a q)+52 \mathrm{H}_{2} \mathrm{O}(l)+109 \mathrm{H}^{+}(a q)$ bacterial tissue
is an intermediate step in the conversion of the nitrogen in organic compounds into nitrate ions. What mass of bacterial tissue is produced in a treatment plant for every $1.0 \times 10^{4} \mathrm{kg}$ of wastewater containing 3.0$\% \mathrm{NH}_{4}^{+}$ ions by mass? Assume that 95$\%$ of the ammonium ions are consumed by the bacteria.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:21

Problem 118

Phosphorus can be prepared from calcium phosphate by the following reaction:
$$
2 \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}(s)+6 \mathrm{SiO}_{2}(s)+10 \mathrm{C}(s) \longrightarrow
$$
$$
6 \mathrm{CaSiO}_{3}(s)+\mathrm{P}_{4}(s)+10 \mathrm{CO}(g)
$$
Phosphorite is a mineral that contains $\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}$ plus other
non-phosphorus-containing compounds. What is the maximum amount of $\mathrm{P}_{4}$ that can be produced from 1.0 $\mathrm{kg}$ of phosphorite if the phorphorite sample is 75$\% \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}$ by mass? Assume an excess of the other reactants.

MP
Mihir Paranjape
Numerade Educator
01:51

Problem 119

Coke is an impure form of carbon that is often used in the industrial production of metals from their oxides. If a sample of coke is 95$\%$ carbon by mass, determine the mass of coke needed to react completely with 1.0 ton of copper(Il) oxide.
$$
2 \mathrm{CuO}(s)+\mathrm{C}(s) \longrightarrow 2 \mathrm{Cu}(s)+\mathrm{CO}_{2}(g)
$$

Ronald Prasad
Ronald Prasad
Numerade Educator
08:45

Problem 120

The space shuttle environmental control system handled excess $\mathrm{CO}_{2}$ (which the astronauts breathe out; it is 4.0$\%$ by mass of exhaled air) by reacting it with lithium hydroxide,
LiOH, pellets to form lithium carbonate, Li $_{2} \mathrm{CO}_{3},$ and water. If there were seven astronauts on board the shuttle, and each exhales $20 .$ L of air per minute, how long could clean air be
generated if there were $25,000$ g of LiOH pellets available for each shuttle mission? Assume the density of air is 0.0010 $\mathrm{g} / \mathrm{mL}$ .

Kevin Chimex
Kevin Chimex
Numerade Educator
01:09

Problem 121

Consider the reaction between $\mathrm{NO}(g)$ and $\mathrm{O}_{2}(g)$ represented below.
What is the balanced equation for this reaction, and what is the limiting reactant?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:44

Problem 122

Consider the following reaction:
$$
4 \mathrm{NH}_{3}(g)+5 \mathrm{O}_{2}(g) \longrightarrow 4 \mathrm{NO}(g)+6 \mathrm{H}_{2} \mathrm{O}(g)
$$
If a container were to have 10 molecules of $\mathrm{O}_{2}$ and 10 molecules of $\mathrm{NH}_{3}$ initially, how many total molecules (reactants plus products) would be present in the container after this
reaction goes to completion?

Kevin Chimex
Kevin Chimex
Numerade Educator
04:24

Problem 123

Ammonia is produced from the reaction of nitrogen and hydrogen according to the following balanced equation:
$$
\mathrm{N}_{2}(g)+3 \mathrm{H}_{2}(g) \longrightarrow 2 \mathrm{NH}_{3}(g)
$$
a. What is the maximum mass of ammonia that can be produced from a mixture of $1.00 \times 10^{3} \mathrm{g} \mathrm{N}_{2}$ and $5.00 \times 10^{2} \mathrm{g} \mathrm{H}_{2} ?$
b. What mass of which starting material would remain unreacted?

Ronald Prasad
Ronald Prasad
Numerade Educator
08:16

Problem 124

Consider the following unbalanced equation:
$$
\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}(s)+\mathrm{H}_{2} \mathrm{SO}_{4}(a q) \longrightarrow \mathrm{CaSO}_{4}(s)+\mathrm{H}_{3} \mathrm{PO}_{4}(a q)
$$
What masses of calcium sulfate and phosphoric acid can be produced from the reaction of 1.0 $\mathrm{kg}$ calcium phosphate with 1.0 $\mathrm{kg}$ concentrated sulfuric acid $\left(98 \% \mathrm{H}_{2} \mathrm{SO}_{4} \text { by mass)? }\right.$

Kevin Chimex
Kevin Chimex
Numerade Educator
04:51

Problem 125

Hydrogen peroxide is used as a cleansing agent in the treatment of cuts and abrasions for several reasons. It is an oxidizing agent that can directly kill many microorganisms; it decomposes on contact with blood, releasing elemental oxygen gas (which inhibits the growth of anaerobic microorganisms); and it foams on contact with blood, which provides a cleansing action. In the laboratory, small quantities of hydrogen peroxide can be prepared by the action of an acid on an alkaline earth metal peroxide, such as barium peroxide:
$$
\mathrm{BaO}_{2}(s)+2 \mathrm{HCl}(a q) \longrightarrow \mathrm{H}_{2} \mathrm{O}_{2}(a q)+\mathrm{BaCl}_{2}(a q)
$$
What mass of hydrogen peroxide should result when 1.50 $\mathrm{g}$ barium peroxide is treated with 88.0 $\mathrm{mL}$ hydrochloric acid solution containing 0.0272 $\mathrm{g} \mathrm{HCl}$ per mL? What mass of which reagent is left unreacted?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:19

Problem 126

Silver sulfadiazine burn-treating cream creates a barrier against bacterial invasion and releases antimicrobial agents directly into the wound. If 25.0 $\mathrm{g} \mathrm{Ag}_{2} \mathrm{O}$ is reacted with 50.0 $\mathrm{g} \mathrm{C}_{10} \mathrm{H}_{10} \mathrm{N}_{4} \mathrm{SO}_{2}$ what mass of silver sulfadiazine, $\mathrm{AgC}_{10} \mathrm{H}_{9} \mathrm{N}_{4} \mathrm{SO}_{2},$ can be produced, assuming 100$\%$ yield?
$$
\mathrm{Ag}_{2} \mathrm{O}(s)+2 \mathrm{C}_{10} \mathrm{H}_{10} \mathrm{N}_{4} \mathrm{SO}_{2}(s) \longrightarrow 2 \mathrm{AgC}_{10} \mathrm{H}_{9} \mathrm{N}_{4} \mathrm{SO}_{2}(s)+\mathrm{H}_{2} \mathrm{O}(l)
$$

Anthony Han
Anthony Han
Numerade Educator
05:23

Problem 127

Hydrogen cyanide is produced industrially from the reaction of gaseous ammonia, oxygen, and methane:
$$
2 \mathrm{NH}_{3}(g)+3 \mathrm{O}_{2}(g)+2 \mathrm{CH}_{4}(g) \longrightarrow 2 \mathrm{HCN}(g)+6 \mathrm{H}_{2} \mathrm{O}(g)
$$
If $5.00 \times 10^{3}$ kg each of $\mathrm{NH}_{3}, \mathrm{O}_{2},$ and $\mathrm{CH}_{4}$ are reacted, what mass of $\mathrm{HCN}$ and of $\mathrm{H}_{2} \mathrm{O}$ will be produced, assuming 100$\%$ yield?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:26

Problem 128

Acrylonitrile $\left(\mathrm{C}_{3} \mathrm{H}_{3} \mathrm{N}\right)$ is the starting material for many synthetic carpets and fabrics. It is produced by the following reaction.
$$
2 \mathrm{C}_{3} \mathrm{H}_{6}(g)+2 \mathrm{NH}_{3}(g)+3 \mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{C}_{3} \mathrm{H}_{3} \mathrm{N}(g)+6 \mathrm{H}_{2} \mathrm{O}(g)
$$
If $15.0 \mathrm{g} \mathrm{C}_{3} \mathrm{H}_{6}, 10.0 \mathrm{g} \mathrm{O}_{2},$ and 5.00 $\mathrm{g} \mathrm{NH}_{3}$ are reacted, what mass of acrylonitrile can be produced, assuming 100$\%$ yield?

Kevin Chimex
Kevin Chimex
Numerade Educator
View

Problem 129

Aluminum reacts with bromine, producing aluminum bromide:
$$
2 \mathrm{Al}(s)+3 \mathrm{Br}_{2}(l) \rightarrow 2 \mathrm{AlBr}_{3}(s)
$$
In a certain experiment, 20.0 $\mathrm{mL}$ of bromine (density $=$ 3.10 $\mathrm{g} / \mathrm{mL}$ ) was reacted with excess aluminum to yield 50.3 $\mathrm{g}$ of aluminum bromide. What is the percent yield for this experiment?

Ronald Prasad
Ronald Prasad
Numerade Educator
View

Problem 130

Hexamethylenediamine $\left(\mathrm{C}_{6} \mathrm{H}_{6} \mathrm{N}_{2}\right)$ is one of the starting materials for the production of nylon. It can be prepared from adipic acid $\left(\mathrm{C}_{6} \mathrm{H}_{10} \mathrm{O}_{4}\right)$ by the following overall equation:
$$
\mathrm{C}_{6} \mathrm{H}_{10} \mathrm{O}_{4}(l)+2 \mathrm{NH}_{3}(g)+4 \mathrm{H}_{2}(g) \rightarrow \mathrm{C}_{6} \mathrm{H}_{16} \mathrm{N}_{2}(l)+4 \mathrm{H}_{2} \mathrm{O}(l)
$$
What is the percent yield for the reaction if 765 g of hexamethylenediamine is made from $1.00 \times 10^{3} \mathrm{g}$ of adipic acid?

Jean Gephart
Jean Gephart
Numerade Educator
03:42

Problem 131

The reaction of ethane gas $\left(\mathrm{C}_{2} \mathrm{H}_{6}\right)$ with chlorine gas produces
$\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl}$ as its main product (along with HCl). In addition, the reaction invariably produces a variety of other minor products, including $\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{Cl}_{2}, \mathrm{C}_{2} \mathrm{H}_{3} \mathrm{Cl}_{3},$ and others. Naturally, the production of these minor products reduces the yield of the main product. Calculate the percent yield of $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl}$ if the reaction of $300 . \mathrm{g}$
of ethane with $650 . \mathrm{g}$ of chlorine produced $490 . \mathrm{g}$ of $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl}$

Ronald Prasad
Ronald Prasad
Numerade Educator
06:40

Problem 132

DDT, an insecticide harmful to fish, birds, and humans, is produced by the following reaction:
$$
2 \mathrm{C}_{\mathrm{f}} \mathrm{H}_{5} \mathrm{Cl}+\mathrm{C}_{2} \mathrm{HOCl}_{3} \longrightarrow \mathrm{C}_{14} \mathrm{H}_{9} \mathrm{Cl}_{5}+\mathrm{H}_{2} \mathrm{O}
$$
In a government lab, 1142 g of chlorobenzene is reacted with 485 g of chloral.
a. What mass of DDT is formed, assuming 100$\%$ yield?
b. Which reactant is limiting? Which is in excess?
c. What mass of the excess reactant is left over?
d. If the actual yield of DDT is 200.0 g, what is the percent yield?

Tracy Tourville
Tracy Tourville
Numerade Educator
View

Problem 133

Bornite $\left(\mathrm{Cu}_{3} \mathrm{Fe} \mathrm{S}_{3}\right)$ is a copper ore used in the production of copper. When heated, the following reaction occurs:
$$
2 \mathrm{Cu}_{3} \mathrm{FeS}_{3}(s)+7 \mathrm{O}_{2}(g) \longrightarrow 6 \mathrm{Cu}(s)+2 \mathrm{FeO}(s)+6 \mathrm{SO}_{2}(g)
$$
If 2.50 metric tons of bornite is reacted with excess $\mathrm{O}_{2}$ and the process has an 86.3$\%$ yield of copper, what mass of copper is produced?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
07:18

Problem 134

Consider the following unbalanced reaction:
$$
\mathrm{P}_{4}(s)+\mathrm{F}_{2}(g) \longrightarrow \mathrm{PF}_{3}(g)
$$
What mass of $\mathrm{F}_{2}$ is needed to produce $120 . \mathrm{g}$ of $\mathrm{PF}_{3}$ if the reaction has a 78.1$\%$ yield?

Kevin Chimex
Kevin Chimex
Numerade Educator
01:16

Problem 135

In using a mass spectrometer, a chemist sees a peak at a mass of 30.0106 . Of the choices $^{12} \mathrm{C}_{2}^{1} \mathrm{H}_{6},^{12} \mathrm{C}^{1} \mathrm{H}_{2}^{16} \mathrm{O},$ and $^{14} \mathrm{N}^{16} \mathrm{O}$ which is responsible for this peak? Pertinent masses are $^{1} \mathrm{H}$ $1.007825 ; 16 \mathrm{O}, 15.994915 ;$ and $^{14} \mathrm{N}, 14.003074$

Ronald Prasad
Ronald Prasad
Numerade Educator
04:23

Problem 136

Boron consists of two isotopes, 10 $\mathrm{B}$ and 11 $\mathrm{B}$ . Chlorine also has two isotopes, 35 $\mathrm{Cl}$ and 37 $\mathrm{Cl}$ . Consider the mass spectrum of $\mathrm{BCl}_{3}$ . How many peaks would be present, and what approximate mass would each peak correspond to in the BCl_ mass spectrum?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:17

Problem 137

A given sample of a xenon fluoride compound contains molecules of the type $\mathrm{XeF}_{n},$ where $n$ is some whole number. Given that $9.03 \times 10^{20}$ molecules of $\mathrm{XeF}_{n}$ weigh $0.368 \mathrm{g},$ determine the value for $n$ in the formula.

Ronald Prasad
Ronald Prasad
Numerade Educator
10:48

Problem 138

Aspartame is an artificial sweetener that is 160 times sweeter than sucrose (table sugar) when dissolved in water. It is marketed as NutraSweet. The molecular formula of aspartame is $\mathrm{C}_{14} \mathrm{H}_{18} \mathrm{N}_{2} \mathrm{O}_{5}$
a. Calculate the molar mass of aspartame.
b. What amount (moles) of molecules are present in 10.0 $\mathrm{g}$ aspartame?
c. Calculate the mass in grams of 1.56 mole of aspartame.
d. What number of molecules are in 5.0 mg aspartame?
e. What number of atoms of nitrogen are in 1.2 g aspartame?
f. What is the mass in grams of $1.0 \times 10^{9}$ molecules of aspartame?
g. What is the mass in grams of one molecule of aspartame?

Jennifer Hudspeth
Jennifer Hudspeth
Numerade Educator
02:24

Problem 139

Anabolic steroids are performance enhancement drugs whose use has been banned from most major sporting activities. One anabolic steroid is fluoxymesterone $\left(\mathrm{C}_{20} \mathrm{H}_{29} \mathrm{FO}_{3}\right)$ . Calculate the percent composition by mass of fluoxymesterone.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:48

Problem 140

In the spring of $1984,$ concern arose over the presence of ethylene dibromide, or EDB, in grains and cereals. EDB has the molecular formula $\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{Br}_{2}$ and until 1984 was commonly used as a plant fumigant. The federal limit for $\mathrm{EDB}$ in finished cereal products is 30.0 parts per billion (ppb), where $1.0 \mathrm{ppb}=$ $1.0 \times 10^{-9} \mathrm{g}$ of $\mathrm{EDB}$ for every 1.0 $\mathrm{g}$ of sample. How many molecules of EDB are in 1.0 lb of flour if 30.0 ppb of EDB is present?

Kevin Chimex
Kevin Chimex
Numerade Educator
01:34

Problem 141

You find a compound composed only of element $X$ and chlorine, and you know that the compound is 13.10$\%$ X by mass. Each molecule of the compound contains six times as many chlorine atoms as $\mathrm{X}$ atoms. What is element X?

Ronald Prasad
Ronald Prasad
Numerade Educator
07:12

Problem 142

What mass of sodium hydroxide has the same number of oxygen atoms as 100.0 $\mathrm{g}$ of ammonium carbonate?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:11

Problem 143

The compound adrenaline contains $56.79 \% \mathrm{C}, 6.56 \% \mathrm{H}$ , $28.37 \% \mathrm{O},$ and 8.28$\% \mathrm{N}$ by mass. What is the empirical formula for adrenaline?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:34

Problem 144

Adipic acid is an organic compound composed of 49.31$\% \mathrm{C}$ , $43.79 \% \mathrm{O},$ and the rest hydrogen. If the molar mass of adipic acid is 146.1 $\mathrm{g} / \mathrm{mol}$ , what are the empirical and molecular formulas for adipic acid?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:00

Problem 145

Vitamin $\mathrm{B}_{12},$ cyanocobalamin, is essential for human nutrition. It is concentrated in animal tissue but not in higher plants. Although nutritional requirements for the vitamin are quite low, people who abstain completely from animal products may develop a deficiency anemia. Cyanocobalamin is the form used in vitamin supplements. It contains 4.34$\%$ cobalt by mass. Calculate the molar mass of cyanocobalamin, assuming that there is one atom of cobalt in every molecule of cyanocobalamin.

Ronald Prasad
Ronald Prasad
Numerade Educator
04:09

Problem 146

Some bismuth tablets, a medication used to treat upset stomachs, contain 262 $\mathrm{mg}$ of bismuth subsalicylate, $\mathrm{C}_{7} \mathrm{H}_{5} \mathrm{BiO}_{4},$ per tablet. Assuming two tablets are digested, calculate the mass of bismuth consumed.

Kevin Chimex
Kevin Chimex
Numerade Educator
02:34

Problem 147

The empirical formula of styrene is $\mathrm{CH} ;$ the molar mass of styrene is 104.14 $\mathrm{g} / \mathrm{mol}$ . What number of $\mathrm{H}$ atoms are present in a 2.00 -g sample of styrene?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:39

Problem 148

Terephthalic acid is an important chemical used in the manufacture of polyesters and plasticizers. It contains only $\mathrm{C}, \mathrm{H}$ , and O. Combustion of 19.81 $\mathrm{mg}$ terephthalic acid produces 41.98 $\mathrm{mg} \mathrm{CO}_{2}$ and 6.45 $\mathrm{mg} \mathrm{H}_{2} \mathrm{O}$ . If 0.250 mole of terephthalic acid has a mass of $41.5 \mathrm{g},$ determine the molecular formula for terephthalic acid.

Kevin Chimex
Kevin Chimex
Numerade Educator
04:36

Problem 149

A sample of a hydrocarbon (a compound consisting of only carbon and hydrogen contains $2.59 \times 10^{23}$ atoms of hydrogen and is 17.3$\%$ hydrogen by mass. If the molar mass of the hydrocarbon is between 55 and 65 g/mol, what amount (moles) of compound is present, and what is the mass of the sample?

Ronald Prasad
Ronald Prasad
Numerade Educator
01:37

Problem 150

A binary compound between an unknown element $\mathrm{E}$ and hydrogen contains 91.27$\% \mathrm{E}$ and 8.73$\% \mathrm{H}$ by mass. If the formula of the compound is $\mathrm{E}_{3} \mathrm{H}_{8},$ calculate the atomic mass of $\mathrm{E}$

Ma Ednelyn Lim
Ma Ednelyn Lim
Numerade Educator
02:23

Problem 151

A 0.755 -g sample of hydrated copper(II) sulfate
$$
\mathrm{CuSO}_{4} \cdot x \mathrm{H}_{2} \mathrm{O}
$$
was heated carefully until it had changed completely to anhydrous copper(II) sulfate $\left(\mathrm{CuSO}_{4}\right)$ with a mass of 0.483 g. Determine the value of $x .[\text { This number is called the number of waters }$ of hydration of copper(Il) sulfate. It specifies the number of water
molecules per formula unit of $\mathrm{CuSO}_{4}$ in the hydrated crystal. $]$

Ronald Prasad
Ronald Prasad
Numerade Educator
05:24

Problem 152

ABS plastic is a tough, hard plastic used in applications requiring shock resistance. The polymer consists of three monomer units: acrylonitrile $\left(\mathrm{C}_{3} \mathrm{H}_{3} \mathrm{N}\right),$ butadiene $\left(\mathrm{C}_{4} \mathrm{H}_{6}\right),$ and styrene $\left(\mathrm{C}_{8} \mathrm{H}_{8}\right)$
a. A sample of ABS plastic contains 8.80$\% \mathrm{N}$ by mass. It took 0.605 $\mathrm{g}$ of $\mathrm{Br}_{2}$ to react completely with a $1.20-\mathrm{g}$ sample of $\mathrm{ABS}$ plastic. Bromine reacts $1 : 1$ (by moles) with the butadiene molecules in the polymer and nothing else. What is the percent by mass of acrylonitrile and butadiene in this polymer?
b. What are the relative numbers of each of the monomer units in this polymer?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:35

Problem 153

A sample of LSD (D-lysergic acid diethylamide, $\mathrm{C}_{24} \mathrm{H}_{30} \mathrm{N}_{3} \mathrm{O} )$ is added to some table salt (sodium chloride) to form a mixture. Given that a 1.00 -g sample of the mixture undergoes combustion to produce 1.20 $\mathrm{g}$ of $\mathrm{CO}_{2},$ what is the mass percent of $\mathrm{LSD}$ in the mixture?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:16

Problem 154

Methane $\left(\mathrm{CH}_{4}\right)$ is the main component of marsh gas. Heating methane in the presence of sulfur produces carbon disulfide and hydrogen sulfide as the only products.
a. Write the balanced chemical equation for the reaction of methane and sulfur.
b. Calculate the theoretical yield of carbon disulfide when $120 .$ g of methane is reacted with an equal mass of sulfur.

Christopher Nilsen
Christopher Nilsen
Numerade Educator
02:13

Problem 155

A potential fuel for rockets is a combination of $\mathrm{B}_{5} \mathrm{H}_{9}$ and $\mathrm{O}_{2}$
The two react according to the following balanced equation:
$$
2 \mathrm{B}_{5} \mathrm{H}_{9}(l)+12 \mathrm{O}_{2}(g) \longrightarrow 5 \mathrm{B}_{2} \mathrm{O}_{3}(s)+9 \mathrm{H}_{2} \mathrm{O}(g)
$$
If one tank in a rocket holds 126 $\mathrm{g} \mathrm{B}_{5} \mathrm{H}_{9}$ and another tank holds $192 \mathrm{g} \mathrm{O}_{2},$ what mass of water can be produced when the entire contents of each tank react together?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:33

Problem 156

A $0.4230-$ g sample of impure sodium nitrate was heated, converting all the sodium nitrate to 0.2864 g of sodium nitrite and oxygen gas. Determine the percent of sodium nitrate in the original sample.

Kevin Chimex
Kevin Chimex
Numerade Educator
01:44

Problem 157

An iron ore sample contains $\mathrm{Fe}_{2} \mathrm{O}_{3}$ plus other impurities. A 752 -g sample of impure iron ore is heated with excess carbon, producing 453 g of pure iron by the following reaction:
$$
\mathrm{Fe}_{2} \mathrm{O}_{3}(s)+3 \mathrm{C}(s) \longrightarrow 2 \mathrm{Fe}(s)+3 \mathrm{CO}(g)
$$
What is the mass percent of $\mathrm{Fe}_{2} \mathrm{O}_{3}$ in the impure iron ore sample? Assume that $\mathrm{Fe}_{2} \mathrm{O}_{3}$ is the only source of iron and that the reaction is 100$\%$ efficient.

Ronald Prasad
Ronald Prasad
Numerade Educator
04:13

Problem 158

Commercial brass, an alloy of Zn and Cu, reacts with hydrochloric acid as follows:
$$
\mathrm{Zn}(s)+2 \mathrm{HCl}(a q) \longrightarrow \mathrm{ZnCl}_{2}(a q)+\mathrm{H}_{2}(g)
$$
(Cu does not react with HCl.) When 0.5065 g of a certain brass alloy is reacted with excess $\mathrm{HCl}, 0.0985 \mathrm{g} \mathrm{ZnCl}_{2}$ is eventually isolated.
a. What is the composition of the brass by mass?
b. How could this result be checked without changing the above procedure?

Rabia Shuaib
Rabia Shuaib
Numerade Educator
02:43

Problem 159

Vitamin A has a molar mass of 286.4 $\mathrm{g} / \mathrm{mol}$ and a general molecular formula of $\mathrm{C}_{x} \mathrm{H}, \mathrm{E}$ , where $\mathrm{E}$ is an unknown element. If vitamin $\mathrm{A}$ is 83.86$\% \mathrm{C}$ and 10.56$\% \mathrm{H}$ by mass, what is the molecular formula of vitamin A?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:33

Problem 160

You have seven closed containers, each with equal masses of chlorine gas $\left(\mathrm{Cl}_{2}\right) .$ You add 10.0 $\mathrm{g}$ of sodium to the first sample, 20.0 $\mathrm{g}$ of sodium to the second sample, and so on (adding 70.0 $\mathrm{g}$ of sodium to the seventh sample). Sodium and chlorine
react to form sodium chloride according to the equation
$$
2 \mathrm{Na}(s)+\mathrm{Cl}_{2}(g) \longrightarrow 2 \mathrm{NaCl}(s)
$$
After each reaction is complete, you collect and measure the amount of sodium chloride formed. A graph of your results is shown below.
Answer the following questions:
a. Explain the shape of the graph.
b. Calculate the mass of NaCl formed when 20.0 $\mathrm{g}$ of sodium is used.
c. Calculate the mass of $\mathrm{Cl}_{2}$ in each container.
d. Calculate the mass of NaCl formed when 50.0 $\mathrm{g}$ of sodium is used.
e. Identify the leftover reactant, and determine its mass for parts b and d above.

Lottie Adams
Lottie Adams
Numerade Educator
02:13

Problem 161

A substance $\mathrm{X}_{2} \mathrm{Z}$ has the composition (by mass) of 40.0\% X and 60.0$\% \mathrm{Z}$ . What is the composition (by mass) of the compound $\mathrm{XZ}_{2} ?$

Ronald Prasad
Ronald Prasad
Numerade Educator
05:35

Problem 162

Consider samples of phosphine $\left(\mathrm{PH}_{3}\right),$ water $\left(\mathrm{H}_{2} \mathrm{O}\right),$ hydrogen sulfide $\left(\mathrm{H}_{2} \mathrm{S}\right),$ and hydrogen fluoride (HF), each with a mass of 119 $\mathrm{g} .$ Rank the compounds from the least to the greatest number of hydrogen atoms contained in the samples.

Kevin Chimex
Kevin Chimex
Numerade Educator
02:14

Problem 163

Calculate the number of moles for each compound in the following table.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:52

Problem 164

Arrange the following substances in order of increasing mass percent of nitrogen.
$\begin{array}{ll}{\text { a. } \mathrm{NO}} & {\text { c. } \mathrm{NH}_{3}} \\ {\text { b. } \mathrm{N}_{2} \mathrm{O}} & {\text { d. SNH }}\end{array}$

Kevin Chimex
Kevin Chimex
Numerade Educator
05:38

Problem 165

Para-cresol, a substance used as a disinfectant and in the manufacture of several herbicides, is a molecule that contains the elements carbon, hydrogen, and oxygen. Complete combustion of a $0.345-\mathrm{g}$ sample of $p$ -cresol produced 0.983 g carbon dioxide and 0.230 $\mathrm{g}$ water. Determine the empirical formula for $p$ -cresol.

Ronald Prasad
Ronald Prasad
Numerade Educator
06:12

Problem 166

A compound with molar mass 180.1 $\mathrm{g} / \mathrm{mol}$ has the following composition by mass: Determine the empirical and molecular formulas of the compound.

Jennifer Hudspeth
Jennifer Hudspeth
Numerade Educator
01:13

Problem 167

Which of the following statements about chemical equations is(are) true?
a. When balancing a chemical equation, you can never change the coefficient in front of any chemical formula.
b. The coefficients in a balanced chemical equation refer to the number of grams of reactants and products.
c. In a chemical equation, the reactants are on the right and the products are on the left.
d. When balancing a chemical equation, you can never change the subscripts of any chemical formula.
e. In chemical reactions, matter is neither created nor destroyed so a chemical equation must have the same number of atoms on both sides of the equation.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:38

Problem 168

Consider the following unbalanced chemical equation for the combustion of pentane $\left(\mathrm{C}_{5} \mathrm{H}_{12}\right) :$
$$
\mathrm{C}_{5} \mathrm{H}_{12}(l)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(l)
$$
If 20.4 g of pentane are burned in excess oxygen, what mass of water can be produced, assuming 100$\%$ yield?

Kevin Chimex
Kevin Chimex
Numerade Educator
04:40

Problem 169

Sulfur dioxide gas reacts with sodium hydroxide to form sodium sulfite and water. The unbalanced chemical equation for this reaction is given below:
$$
\mathrm{SO}_{2}(g)+\mathrm{NaOH}(s) \longrightarrow \mathrm{Na}_{2} \mathrm{SO}_{3}(s)+\mathrm{H}_{2} \mathrm{O}(l)
$$
Assuming you react 38.3 g sulfur dioxide with 32.8 g sodium hydroxide and assuming that the reaction goes to completion, calculate the mass of each product formed.

Ronald Prasad
Ronald Prasad
Numerade Educator
08:02

Problem 170

Gallium arsenide, GaAs, has gained widespread use in semi-conductor devices that convert light and electrical signals in fiber-optic communications systems. Gallium consists of $60 . \%$ o' Ga and $40 . \%$ ?1 Ga. Arsenic has only one naturally occurring isotope, 75 As. Gallium arsenide is a polymeric material, but its mass spectrum shows fragments with the formulas GaAs and $\mathrm{Ga}_{2} \mathrm{As}_{2}$ . What would the distribution of peaks look like for these two fragments?

Kevin Chimex
Kevin Chimex
Numerade Educator
03:22

Problem 171

Consider the following data for three binary compounds of hydrogen and nitrogen:
When 1.00 $\mathrm{L}$ of each gaseous compound is decomposed to its elements, the following volumes of $\mathrm{H}_{2}(g)$ and $\mathrm{N}_{2}(g)$ are obtained:
Use these data to determine the molecular formulas of compounds I, II, and III and to determine the relative values for the atomic masses of hydrogen and nitrogen.

Ronald Prasad
Ronald Prasad
Numerade Educator
09:51

Problem 172

Natural rubidium has the average mass of 85.4678 $\mathrm{u}$ and is composed of isotopes $^{85} \mathrm{Rb}(\mathrm{mass}=84.9117 \mathrm{u})$ and $^{87} \mathrm{Rb}$ . The ratio of atoms $^{85} \mathrm{Rb} /^{87} \mathrm{Rb}$ in natural rubidium is $2.591 .$ Calculate the mass of $^{87} \mathrm{Rb}$ .

Kevin Chimex
Kevin Chimex
Numerade Educator
06:41

Problem 173

A compound contains only carbon, hydrogen, nitrogen, and oxygen. Combustion of 0.157 $\mathrm{g}$ of the compound produced 0.213 $\mathrm{g} \mathrm{CO}_{2}$ and 0.0310 $\mathrm{g} \mathrm{H}_{2} \mathrm{O}$ . In another experiment, it is found that 0.103 $\mathrm{g}$ of the compound produces 0.0230 $\mathrm{g} \mathrm{NH}_{3} .$ What is the empirical formula of the compound? Hint: Combustion involves reacting with excess $\mathrm{O}_{2}$ . Assume that all the carbon ends up in $\mathrm{CO}_{2}$ and all the hydrogen ends up in $\mathrm{H}_{2} \mathrm{O}$ . Also assume that all the nitrogen ends up in the $\mathrm{NH}_{3}$ in the second experiment.

Ronald Prasad
Ronald Prasad
Numerade Educator
04:39

Problem 174

Nitric acid is produced commercially by the Ostwald process, represented by the following equations:
$$
\begin{aligned} 4 \mathrm{NH}_{3}(g)+5 \mathrm{O}_{2}(g) & \longrightarrow 4 \mathrm{NO}(g)+6 \mathrm{H}_{2} \mathrm{O}(g) \\ 2 \mathrm{NO}(g)+\mathrm{O}_{2}(g) & \longrightarrow 2 \mathrm{NO}_{2}(g) \\ 3 \mathrm{NO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(l) & \longrightarrow 2 \mathrm{HNO}_{3}(a q)+\mathrm{NO}(g) \end{aligned}
$$
What mass of $\mathrm{NH}_{3}$ must be used to produce $1.0 \times 10^{6} \mathrm{kg}$ $\mathrm{HNO}_{3}$ by the Ostwald process? Assume 100$\%$ yield in each reaction, and assume that the NO produced in the third step is not recycled.

Jennifer Hudspeth
Jennifer Hudspeth
Numerade Educator
05:57

Problem 175

When the supply of oxygen is limited, iron metal reacts with oxygen to produce a mixture of $\mathrm{FeO}$ and $\mathrm{Fe}_{2} \mathrm{O}_{3} .$ In a certain experiment, 20.00 $\mathrm{g}$ iron metal was reacted with 11.20 $\mathrm{g}$ oxygen gas. After the experiment, the iron was totally consumed, and 3.24 $\mathrm{g}$ oxygen gas remained. Calculate the amounts of $\mathrm{FeO}$ and $\mathrm{Fe}_{2} \mathrm{O}_{3}$ formed in this experiment.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:45

Problem 176

A 9.780 -g gaseous mixture contains ethane $\left(\mathrm{C}_{2} \mathrm{H}_{6}\right)$ and propane $\left(\mathrm{C}_{3} \mathrm{H}_{8}\right) .$ Complete combustion to form carbon dioxide and water requires 1.120 $\mathrm{mole}$ of oxygen gas. Calculate the mass percent of ethane in the original mixture.

Tracy Tourville
Tracy Tourville
Numerade Educator
03:20

Problem 177

Zinc and magnesium metal each reacts with hydrochloric acid to make chloride salts of the respective metals, and hydrogen gas. A 10.00 -g mixture of zinc and magnesium produces 0.5171 g of hydrogen gas upon being mixed with an excess of hydrochloric acid. Determine the percent magnesium by mass in the original mixture.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:54

Problem 178

A gas contains a mixture of $\mathrm{NH}_{3}(g)$ and $\mathrm{N}_{2} \mathrm{H}_{4}(g),$ both of which react with $\mathrm{O}_{2}(g)$ to form $\mathrm{NO}_{2}(g)$ and $\mathrm{H}_{2} \mathrm{O}(g) .$ The gaseous mixture (with an initial mass of 61.00 $\mathrm{g}$ ) is reacted with 10.00 $\mathrm{moles}$ $\mathrm{O}_{2},$ and after the reaction is complete, 4.062 moles of $\mathrm{O}_{2}$ remains. Calculate the mass percent of $\mathrm{N}_{2} \mathrm{H}_{4}(g)$ in the original gaseous mixture.

Nicholas Mogoi
Nicholas Mogoi
Numerade Educator
05:58

Problem 179

Consider a gaseous binary compound with a molar mass of 62.09 $\mathrm{g} / \mathrm{mol} .$ When 1.39 $\mathrm{g}$ of this compound is completely burned in excess oxygen, 1.21 $\mathrm{g}$ of water is formed. Determine the formula of the compound. Assume water is the only product that contains hydrogen.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:36

Problem 180

A $2.25-$ g sample of scandium metal is reacted with excess hydrochloric acid to produce 0.1502 g hydrogen gas. What is the formula of the scandium chloride produced in the reaction?

Anthony Han
Anthony Han
Numerade Educator
03:02

Problem 181

In the production of printed circuit boards for the electronics industry, a 0.60 -mm layer of copper is laminated onto an insulating plastic board. Next, a circuit pattern made of a chemically resistant polymer is printed on the board. The unwanted copper is removed by chemical etching, and the protective polymer is finally removed by solvents. One etching reaction is
$$
\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}(a q)+4 \mathrm{NH}_{3}(a q)+\mathrm{Cu}(s) \longrightarrow
$$
$$
2 \mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}(a q)
$$
A plant needs to manufacture $10,000$ printed circuit boards, each $8.0 \times 16.0 \mathrm{cm}$ in area. An average of $80 . \%$ of the copper is removed from each board (density of copper $=8.96 \mathrm{g} / \mathrm{cm}^{3}$ . What masses of $\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}$ and $\mathrm{NH}_{3}$ are needed to do this? Assume 100$\%$ yield.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:51

Problem 182

The aspirin substitute, acetaminophen $\left(\mathrm{C}_{8} \mathrm{H}_{9} \mathrm{O}_{2} \mathrm{N}\right),$ is produced by the following three-step synthesis:
$$
\mathrm{I} . \quad \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{3} \mathrm{N}(s)+3 \mathrm{H}_{2}(g)+\mathrm{HCl}(a q) \longrightarrow
$$
$$
\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{ONCl}(s)+2 \mathrm{H}_{2} \mathrm{O}(l)
$$
$$
\mathrm{II}\quad \mathrm{C}_{6} \mathrm{H}_{8} \mathrm{ONCl}(s)+\mathrm{NaOH}(a q) \longrightarrow
$$
$$
\mathrm{C}_{6} \mathrm{H}_{7} \mathrm{ON}(s)+\mathrm{H}_{2} \mathrm{O}(l)+\mathrm{NaCl}(a q)
$$
$$
\mathrm{III.} \quad \mathrm{C}_{6} \mathrm{H}_{7} \mathrm{ON}(s)+\mathrm{C}_{4} \mathrm{H}_{6} \mathrm{O}_{3}(l) \longrightarrow
$$
$$
\mathrm{C}_{8} \mathrm{H}_{9} \mathrm{O}_{2} \mathrm{N}(s)+\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}(l)
$$
The first two reactions have percent yields of 87$\%$ and 98$\%$ by mass, respectively. The overall reaction yields 3 moles of acetaminophen product for every 4 moles of $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{3} \mathrm{N}$ reacted.
a. What is the percent yield by mass for the overall process?
b. What is the percent yield by mass of Step III?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:09

Problem 183

An element X forms both a dichloride $\left(\mathrm{XCl}_{2}\right)$ and a tetrachloride $\left(\mathrm{XCl}_{4}\right) .$ Treatment of 10.00 $\mathrm{g} \mathrm{XCl}_{2}$ with excess chlorine forms 12.55 $\mathrm{g} \mathrm{XCl}_{4}$ . Calculate the atomic mass of $\mathrm{X},$ and identify $\mathrm{X}$ .

Ronald Prasad
Ronald Prasad
Numerade Educator
03:47

Problem 184

When $\mathrm{M}_{2} \mathrm{S}_{3}(s)$ is heated in air, it is converted to $\mathrm{MO}_{2}(s) . \mathrm{A}$ 4.000 -g sample of $\mathrm{M}_{2} \mathrm{S}_{3}(s)$ shows a decrease in mass of 0.277 $\mathrm{g}$ when it is heated in air. What is the average atomic mass of M?

Kevin Chimex
Kevin Chimex
Numerade Educator
02:17

Problem 185

When aluminum metal is heated with an element from Group 6 $\mathrm{A}$ of the periodic table, an ionic compound forms. When the experiment is performed with an unknown Group 6 $\mathrm{A}$ element, the product is 18.56$\%$ Al by mass. What is the formula of the compound?

Ronald Prasad
Ronald Prasad
Numerade Educator
05:56

Problem 186

Consider a mixture of potassium chloride and potassium nitrate that is 43.2$\%$ potassium by mass. What is the percent $\mathrm{KCl}$ by mass of the original mixture?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:10

Problem 187

Lanthanum was reacted with hydrogen in a given experiment to produce the nonstoichiometric compound $\mathrm{LaH}_{2.90}$ Assuming that the compound contains $\mathrm{H}^{-}, \mathrm{La}^{2+},$ and $\mathrm{La}^{3+},$ calculate the fractions of $\mathrm{La}^{2+}$ and $\mathrm{La}^{3+}$ present.

Ronald Prasad
Ronald Prasad
Numerade Educator
08:19

Problem 188

A 1.500 -g sample of a mixture containing only $\mathrm{Cu}_{2} \mathrm{O}$ and CuO was treated with hydrogen to produce 1.252 $\mathrm{g}$ of pure cupper metal. Calculate the mass percent of $\mathrm{Cu}_{2} \mathrm{O}$ in the original mixture.

Ronald Prasad
Ronald Prasad
Numerade Educator
05:09

Problem 189

Ammonia reacts with $\mathrm{O}_{2}$ to form either $\mathrm{NO}(g)$ or $\mathrm{NO}_{2}(g)$ according to these unbalanced equations:
$$
\begin{array}{l}{\mathrm{NH}_{3}(g)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{NO}(g)+\mathrm{H}_{2} \mathrm{O}(g)} \\ {\mathrm{NH}_{3}(g)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{NO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)}\end{array}
$$
In a certain experiment 2.00 moles of $\mathrm{NH}_{3}(g)$ and 10.00 moles of $\mathrm{O}_{2}(g)$ are contained in a closed flask. After the reaction is complete, 6.75 moles of $\mathrm{O}_{2}(g)$ remains. Calculate the number of moles of $\mathrm{NO}(g)$ in the product mixture: Hint: You cannot do this problem by adding the balanced equations because you cannot assume that the two reactions will occur with equal probability.)

Ronald Prasad
Ronald Prasad
Numerade Educator
11:36

Problem 190

You take 1.00 g of an aspirin tablet (a compound consisting solely of carbon, hydrogen, and oxygen), burn it in air, and collect 2.20 $\mathrm{g} \mathrm{CO}_{2}$ and 0.400 $\mathrm{g} \mathrm{H}_{2} \mathrm{O} .$ You know that the molar mass of aspirin is between 170 and 190 $\mathrm{g} / \mathrm{mol}$ . Reacting 1 $\mathrm{mole}$ of salicylic acid with 1 mole of acetic anhydride $\left(\mathrm{C}_{4} \mathrm{H}_{6} \mathrm{O}_{3}\right)$ gives you 1 mole of aspirin and 1 mole of acetic acid $\left(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}\right)$ Use this information to determine the molecular formula of salicylic acid.

Kevin Chimex
Kevin Chimex
Numerade Educator
01:42

Problem 191

With the advent of techniques such as scanning tunneling microscopy, it is now possible to "write" with individual atoms by manipulating and arranging atoms on an atomic surface.
a. If an image is prepared by manipulating iron atoms and their total mass is $1.05 \times 10^{-20} \mathrm{g},$ what number of iron atoms were used?
b. If the image is prepared on a platinum surface that is exactly 20 platinum atoms high and 14 platinum atoms wide, what is the mass (grams) of the atomic surface?
c. If the atomic surface were changed to ruthenium atoms and the same surface mass as determined in part b is used, what number of ruthenium atoms is needed to construct the surface?

Ronald Prasad
Ronald Prasad
Numerade Educator
13:56

Problem 192

Tetrodotoxin is a toxic chemical found in fugu pufferfish, a popular but rare delicacy in Japan. This compound has an LD_s0 (the amount of substance that is lethal to $50 . \%$ of a population sample) of $10 . \mu \mathrm{g}$ per kg of body mass. Tetrodotoxin is 41.38$\%$ carbon by mass, 13.16$\%$ nitrogen by mass, and 5.37$\%$ hydrogen by mass, with the remaining amount consisting of oxygen.
What is the empirical formula of tetrodotoxin? If three molecules of tetrodotoxin have a mass of $1.59 \times 10^{-21}$ g, what is the molecular formula of tetrodotoxin? What number of molecules of tetrodotoxin would be the LD_so dosage for a person weighing 165 $\mathrm{lb}$ ?

Kevin Chimex
Kevin Chimex
Numerade Educator
06:18

Problem 193

An ionic compound $\mathrm{MX}_{3}$ is prepared according to the following unbalanced chemical equation.
$$
\mathrm{M}+\mathrm{X}_{2} \longrightarrow \mathrm{MX}_{3}
$$
A 0.105 -g sample of $\mathrm{X}_{2}$ contains $8.92 \times 10^{20}$ molecules. The compound $\mathrm{MX}_{3}$ consists of 54.47$\% \mathrm{X} \mathrm{by}$ mass. What are the identities of $\mathrm{M}$ and $\mathrm{X}$ , and what is the correct name for $\mathrm{MX}_{3} ?$ Starting with 1.00 $\mathrm{g}$ each of $\mathrm{M}$ and $\mathrm{X}_{2},$ what mass of $\mathrm{MX}_{3} \mathrm{can}$ be prepared?

Ronald Prasad
Ronald Prasad
Numerade Educator
11:18

Problem 194

The compound As $_{2} \mathrm{L}_{4}$ is synthesized by reaction of arsenic metal with arsenic triodide. If a solid cubic block of arsenic $\left(d=5.72 \mathrm{g} / \mathrm{cm}^{3}\right)$ that is 3.00 $\mathrm{cm}$ on edge is allowed to react with $1.01 \times 10^{24}$ molecules of arsenic triodide, what mass of $\mathrm{As}_{2} \mathrm{L}_{4}$ can be prepared? If the percent yield of $\mathrm{As}_{2} \mathrm{L}_{4}$ was 75.6$\%$ what mass of $\mathrm{As}_{2} \mathrm{I}_{4}$ was actually isolated?

Kevin Chimex
Kevin Chimex
Numerade Educator
01:03

Problem 195

A 2.077 -g sample of an element, which has an atomic mass between 40 and $55,$ reacts with oxygen to form 3.708 g of an oxide. Determine the formula of the oxide (and identify the element).

Ronald Prasad
Ronald Prasad
Numerade Educator
14:46

Problem 196

Consider the following balanced chemical equation:
$$
\mathrm{A}+5 \mathrm{B} \longrightarrow 3 \mathrm{C}+4 \mathrm{D}
$$
a. Equal masses of A and B are reacted. Complete each of the following with either “A is the limiting reactant because ________”; “B is the limiting reactant because ________”; or “we cannot determine the limiting reactant because ________.” i. If the molar mass of A is greater than the molar mass of B, then ii. If the molar mass of B is greater than the molar mass of A, then b. The products of the reaction are carbon dioxide (C) and water (D). Compound A has a similar molar mass to carbon dioxide. Compound B is a diatomic molecule. Identify compound B, and support your answer. c. Compound A is a hydrocarbon that is 81.71% carbon by mass. Determine its empirical and molecular formulas.

Tianyu Li
Tianyu Li
Numerade Educator