Chemistry Matter and Change

Thandi Buthelezi, Laurel Dingrando, Nicholas Hainen Cheryl Wistrom, Dinah Zike

Chapter 10

The Mole - all with Video Answers

Educators

+ 17 more educators

Chapter Questions

Problem 1

Zinc (Zn) is used to form a corrosion-inhibiting surface on galvanized steel. Determine the number of Zn atoms in 2.50 mol of Zn

Sharfa Farzandh

Sharfa Farzandh

Numerade Educator

Problem 2

Calculate the number of molecules in 11.5 mol of water $\left(\mathrm{H}_{2} \mathrm{O}\right)$

Dr. Satish Ingale

Dr. Satish Ingale

Numerade Educator

Problem 3

Silver nitrate $\left(\mathrm{Ag} \mathrm{NO}_{3}\right)$ is used to make several different silver halides used in photographic films. How many formula units of $\mathrm{AgNO}_{3}$ are there in 3.25 $\mathrm{mol}$ of $\mathrm{AgNO}_{3} ?$

Himanshu Garg

Numerade Educator

Problem 4

Challenge Calculate the number of oxygen atoms in 5.0 $\mathrm{mol}$ of oxygen molecules. Oxygen is a diatomic molecule, $\mathrm{O}_{2} .$

Emmalou Schmittzehe

Emmalou Schmittzehe

Numerade Educator

Problem 5

How many moles contain each of the following?
a. $5.75 \times 10^{24}$ atoms Al $\quad$ b. $2.50 \times 10^{20}$ atoms Fe

Lindsey Smaka

Numerade Educator

Problem 6

Challenge Identify the representative particle for each formula, and convert the given number of representative particles to moles
a. $3.75 \times 10^{24} \mathrm{CO}_{2} \quad$ b. $3.58 \times 10^{23} \mathrm{ZnCl}_{2}$

Emmalou Schmittzehe

Emmalou Schmittzehe

Numerade Educator

Problem 7

why chemists use the mole.

Himanshu Garg

Numerade Educator

Problem 8

State the mathematical relationship between Avogadro’s number and 1 mol.

Himanshu Garg

Numerade Educator

Problem 9

List the conversion factors used to convert between particles and moles.

Lindsey Smaka

Numerade Educator

Problem 10

Explain how a mole is similar to a dozen.

Emmalou Schmittzehe

Emmalou Schmittzehe

Numerade Educator

Problem 11

Apply How does a chemist count the number of particles in a given number of moles of a substance?

Lindsey Smaka

Numerade Educator

Problem 12

Calculate the mass of 0.25 mol of carbon-12 atoms.

Emmalou Schmittzehe

Emmalou Schmittzehe

Numerade Educator

Problem 13

Calculate the number of representative particles of each substance.
a. 11.5 $\mathrm{mol} \mathrm{Ag}$
b. 18.0 $\mathrm{mol} \mathrm{H}_{2} \mathrm{O}$
c. 0.150 mol $\mathrm{NaCl}$
d. $1.35 \times 10^{-2} \mathrm{mol} \mathrm{CCH}_{4}$

Himanshu Garg

Numerade Educator

Problem 14

Arrange these three samples from smallest to largest in terms of number of representative particles: $1.25 \times 10^{25}$ atoms of zinc(Zn), 3.56 mol of iron (Fe), and $6.78 \times 10^{22}$ molecules of glucose $\left(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\right)$

Emmalou Schmittzehe

Emmalou Schmittzehe

Numerade Educator

Problem 15

Determine the mass in grams of each of the following.
a. 3.57 mol Al
b. 42.6 mol S

Himanshu Garg

Numerade Educator

Problem 16

Challenge Convert each given quantity in scientific notation to mass in grams expressed in scientific notation.
a. $3.45 \times 10^{2}$ mol $\mathrm{Co}$
b. $2.45 \times 10^{-2} \mathrm{mol} \mathrm{Zn}$

Himanshu Garg

Numerade Educator

Problem 17

Determine the number of moles in each of the following.
a. 25.5 g Ag
b. 300.0 g S

Himanshu Garg

Numerade Educator

Problem 18

Challenge Convert each mass to moles. Express the answer in scientific notation.
a. $1.25 \times 10^{3} \mathrm{g} \mathrm{Zn} \quad$ b. 1.00 $\mathrm{kg} \mathrm{Fe}$

Himanshu Garg

Numerade Educator

Problem 19

How many atoms are in each of the following samples?
a. 55.2 g Li
b. 0.230 g Pb
c. 11.5 g Hg

AC

Alexis Calabrese

Numerade Educator

Problem 20

What is the mass in grams of each of the following?
a. $6.02 \times 10^{24}$ atoms $\mathrm{Bi}$
b. $1.00 \times 10^{24}$ atoms $\mathrm{Mn}$
c. $3.40 \times 10^{22}$ atoms He
d. $1.50 \times 10^{15}$ atoms $\mathrm{N}$
e. $1.50 \times 10^{15}$ atoms $\mathrm{U}$

Himanshu Garg

Numerade Educator

Problem 21

Challenge Convert each given mass to number of representative particles. Identify the type of representative particle, and express the number in scientific notation.
a. $4.56 \times 10^{3} \mathrm{g} \mathrm{Si}$
b. 0.120 $\mathrm{kg} \mathrm{Ti}$

Himanshu Garg

Numerade Educator

Problem 22

Summarize in terms of particles and mass, one-mole quantities of two different monatomic elements.

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 23

State the conversion factors needed to convert between mass and moles of the element fluorine

Lindsey Smaka

Numerade Educator

Problem 24

Explain how molar mass relates the mass of an atom to the mass of a mole of atoms

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 25

Describe the steps used to convert the mass of an element to the number of atoms of the element

Lindsey Smaka

Numerade Educator

Problem 26

Arrange these quantities from smallest to largest in terms of mass: 1.0 mol of $\mathrm{Ar}, 3.0 \times 10^{24}$ atoms of Ne, and 20 $\mathrm{g}$ of $\mathrm{Kr}$ .

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 27

Identify the quantity that is calculated by dividing the molar mass of an element by Avogadro’s number

Himanshu Garg

Numerade Educator

Problem 28

Design a concept map that shows the conversion factors needed to convert between mass, moles, and number of particles.

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 29

Zinc chloride $\left(\mathrm{ZnCl}_{2}\right)$ is used in soldering flux, an alloy used to join two metals together. Determine the moles of $\mathrm{Cl}^{-}$ ions in 2.50 $\mathrm{mol} \mathrm{ZnCl}_{2}$

Lindsey Smaka

Numerade Educator

Problem 30

Plants and animals depend on glucose $\left(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\right)$ as an energy source. Calculate the number of moles of each element in 1.25 $\mathrm{mol} \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}$ .

Himanshu Garg

Numerade Educator

Problem 31

Iron(III) sulfate $\left[\mathrm{Fe}_{2}\left(\mathrm{SO}_{4}\right)_{3}\right]$s sometimes used in the water purification process. Determine the number of moles of sulfate ions present in 3.00 mol of $\mathrm{Fe}_{2}\left(\mathrm{SO}_{4}\right)_{3}$

Himanshu Garg

Numerade Educator

Problem 32

How many moles of oxygen atoms are present in 5.00 mol of diphosphorus pentoxide $\left(\mathrm{P}_{2} \mathrm{O}_{5}\right) ?$

Susan Hallstrom

Susan Hallstrom

Numerade Educator

Problem 33

Challenge Calculate the number of moles of hydrogen atoms in $1.15 \times 10^{1}$ mol of water. Express the answer in scientific notation.

Rithvik Manne

Numerade Educator

Problem 34

Determine the molar mass of each ionic compound.
a. NaOH
b. $\mathrm{CaCl}_{2}$
c. $\mathrm{KC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}$

Himanshu Garg

Numerade Educator

Problem 35

Calculate the molar mass of each molecular compound.
a. $C_{2} H_{5} O H$
b. HCN
c. $\mathrm{CCl}_{4}$

Himanshu Garg

Numerade Educator

Problem 36

Challenge Identify each substance as a molecular compound or an ionic compound, and then calculate its molar mass.
a. $\operatorname{Sr}\left(\mathrm{NO}_{3}\right)_{2}$
b. $\left(\mathrm{NH}_{4}\right]_{3} \mathrm{PO}_{4}$
c. $C_{12} H_{22} O_{11}$

Himanshu Garg

Numerade Educator

Problem 37

The United States chemical industry produces more sulfuric acid $\left(\mathrm{H}_{2} \mathrm{SO}_{4}\right),$ in terms of mass, than any other chemical. What is the mass of 3.25 $\mathrm{mol}$ of $\mathrm{H}_{2} \mathrm{SO}_{4}$ ?

Lindsey Smaka

Numerade Educator

Problem 38

What is the mass of $4.35 \times 10^{-2}$ mol of zinc chloride $\left(\mathrm{ZnCl}_{2}\right) ?$

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 39

Challenge Write the chemical formula for potassium permanganate, and then calculate the mass in grams of 2.55 mol of the compound.

Himanshu Garg

Numerade Educator

Problem 40

Determine the number of moles present in each compound.
a. 22.6 $\mathrm{g} \mathrm{AgNO}_{3}$
b. 6.50 $\mathrm{g} \mathrm{ZnSO}_{4}$
c. 35.0 $\mathrm{g} \mathrm{HCl}$

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 41

Challenge Identify each as an ionic or molecular compound and convert the given mass to moles. Express your answers in scientific notation.
a. 2.50 $\mathrm{kg} \mathrm{Fe}_{2} \mathrm{O}_{3}$
b. 25.4 $\mathrm{mg} \mathrm{PbCl}_{4}$

Himanshu Garg

Numerade Educator

Problem 42

Ethanol $\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)$ , a domestically produced fuel source, is often blended with gasoline. A sample of ethanol has a mass of 45.6 $\mathrm{g} .$
a. How many carbon atoms does the sample contain?
b. How many hydrogen atoms are present?
c. How many oxygen atoms are present?

Himanshu Garg

Numerade Educator

Problem 43

A sample of sodium sulfite $\left(\mathrm{Na}_{2} \mathrm{SO}_{3}\right)$ has a mass of 2.25 $\mathrm{g}$
a. How many Nat ions are present?
b. How many $\mathrm{SO}_{3}^{2-}$ ions are present?
c. What is the mass in grams of one formula unit of $\mathrm{Na}_{2} \mathrm{SO}_{3} ?$

Himanshu Garg

Numerade Educator

Problem 44

A sample of carbon dioxide $\left(\mathrm{CO}_{2}\right)$ has a mass of 52.0 $\mathrm{g}$
a. How many carbon atoms are present?
b. How many oxygen atoms are present?
c. What is the mass in grams of one molecule of $\mathrm{CO}_{2} ?$

Himanshu Garg

Numerade Educator

Problem 45

What mass of sodium chloride (NaCl) contains $4.59 \times 10^{24}$ formula units?

Lindsey Smaka

Numerade Educator

Problem 46

Challenge A sample of silver chromate has a mass of 25.8 g.
a. Write the formula for silver chromate.
b. How many cations are present in the sample?
c. How many anions are present in the sample?
d. What is the mass in grams of one formula unit of silver chromate?

Himanshu Garg

Numerade Educator

Problem 47

Describe how to determine the molar mass of a compound.

Sohini Lahiri

Numerade Educator

Problem 48

Identify the conversion factors needed to convert between the number of moles and the mass of a compound

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 49

Explain how you can determine the number of atoms or ions in a given mass of a compound.

Lindsey Smaka

Numerade Educator

Problem 50

Apply How many moles of $\mathrm{K}, \mathrm{C},$ and 0 atoms are there in 1 $\mathrm{mol}$ of $\mathrm{K}_{2} \mathrm{C}_{2} \mathrm{O}_{4} ?$

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 51

Calculate the molar mass of $\mathrm{MgBr}_{2}$

Lindsey Smaka

Numerade Educator

Problem 52

Calculate Calcium carbonate is the calcium source for many vitamin tablets The recommended daily allowance of calcium is 1000 $\mathrm{mg}$ of $\mathrm{Ca}^{2+}$ ions. How many moles of $\mathrm{Ca}^{2+}$ does 1000 $\mathrm{mg}$ represent?

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 53

Design a bar graph that will show the number of moles of each element present in 500 $\mathrm{g}$ of a particular form of dioxin $\left(\mathrm{C}_{12} \mathrm{H}_{4} \mathrm{Cl}_{4} \mathrm{O}_{2}\right),$ a powerfuul poison.

Pam Owens

Numerade Educator

Problem 54

What is the percent composition of phosphoric acid $\left(\mathrm{H}_{3} \mathrm{PO}_{4}\right) ?$

David Collins

Numerade Educator

Problem 55

Which has the larger percent by mass of sulfur, $\mathrm{H}_{2} \mathrm{SO}_{3}$ or $\mathrm{H}_{2} \mathrm{S}_{2} \mathrm{O}_{8} ?$

Rithvik Manne

Numerade Educator

Problem 56

Calcium chloride $\left(\mathrm{CaCl}_{2}\right)$ is sometimes used as a de-icer. Calculate the percent by mass of each element in $\mathrm{CaCl}_{2}$

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 57

Challenge Sodium sulfate is used in the manufacture of detergents.
a. Identify each of the component elements of sodium sulfate, and write the compound’s chemical formula.
b. Identify the compound as ionic or covalent.
c. Calculate the percent by mass of each element in sodium sulfate.

Matthew Bittner

Matthew Bittner

Numerade Educator

Problem 58

The circle graph at the right gives the percent composition for a blue solid. What is the empirical formula for this solid?

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 59

Determine the empirical formula for a compound that contains 35.98% aluminum and 64.02% sulfur.

Himanshu Garg

Numerade Educator

Problem 60

Propane is a hydrocarbon, a compound composed only of carbon and hydrogen. It is 81.82% carbon and 18.18% hydrogen. What is the empirical formula?

Himanshu Garg

Numerade Educator

Problem 61

Challenge Aspirin is the world’s most-often used medication. The chemical analysis of aspirin indicates that the molecule is 60.00% carbon, 4.44% hydrogen, and 35.56% oxygen. Determine the empirical formula for aspirin.

Himanshu Garg

Numerade Educator

Problem 62

A compound was found to contain 49.98 g of carbon and 10.47 g of hydrogen. The molar mass of the compound is 58.12 g/mol. Determine the molecular formula.

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 63

A colorless liquid composed of 46.68% nitrogen and 53.32% oxygen has a molar mass of 60.01 g/mol. What is the molecular formula?

Himanshu Garg

Numerade Educator

Problem 64

When an oxide of potassium is decomposed, 19.55 g of K and 4.00 g of O are obtained. What is the empirical formula for the compound?

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 65

Challenge Analysis of a chemical used in photographic developing fluid yielded the percent composition data shown in the circle graph to the right. If the chemical’s molar mass is 110.0 g/mol, what is its molecular formula?

Himanshu Garg

Numerade Educator

Problem 66

Challenge Analysis of the pain reliever morphine yielded the data shown in the table. Determine the empirical formula of morphine.

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 67

Assess A classmate tells you that experimental data shows a compound’s molecular formula to be 2.5 times its empirical formula. Is he correct? Explain.

Himanshu Garg

Numerade Educator

Problem 68

Calculate Analysis of a compound composed of iron and oxygen yields 174.86 g of Fe and 75.14 g of O. What is the empirical formula for this compound?

Himanshu Garg

Numerade Educator

Problem 69

Calculate An oxide of aluminum contains 0.545 g of Al and 0.485 g of O. Find the empirical formula for the oxide.

Himanshu Garg

Numerade Educator

Problem 70

Explain how percent composition data for a compound are related to the masses of the elements in the compound.

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 71

Explain how you can find the mole ratio in a chemical compound.

David Collins

Numerade Educator

Problem 72

Apply The molar mass of a compound is twice that of its empirical formula. How are the compound’s molecular and empirical formulas related?

Himanshu Garg

Numerade Educator

Problem 73

Analyze Hematite (Fe $\mathrm{O}_{3}$ ) and magnetite $\left(\mathrm{Fe}_{3} \mathrm{O}_{4}\right)$ are two ores used as sources of iron. Which ore provides the greater percent of iron per kilogram?

Himanshu Garg

Numerade Educator

Problem 74

The composition of a hydrate is given in the circle graph shown at the right. What is the formula and name of this hydrate?

Dr. Satish Ingale

Dr. Satish Ingale

Numerade Educator

Problem 75

Challenge An 11.75-g sample of a common hydrate of cobalt(II) chloride is heated. After heating, 0.0712 mol of anhydrous cobalt chloride remains. What is the formula and the name of this hydrate?

Himanshu Garg

Numerade Educator

Problem 76

ummarize the composition of a hydrate

Himanshu Garg

Numerade Educator

Problem 77

Name the compound that has the formula $\operatorname{Sr} \mathrm{Cl}_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O}$

Himanshu Garg

Numerade Educator

Problem 78

Describe the experimental procedure for determining the formula of a hydrate. Explain the reason for each step.

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 79

Apply A hydrate contains 0.050 mol of $\mathrm{H}_{2} \mathrm{O}$ to every 0.00998 mol of ionic compound. Write a generalized formula of the hydrate.

Lindsey Smaka

Numerade Educator

Problem 80

Calculate the mass of the water of hydration if a hydrate loses 0.025 mol of $\mathrm{H}_{2} \mathrm{O}$ when heated.

Dakota Smith

Numerade Educator

Problem 81

Arrange these hydrates in order of increasing percent water content:
$\mathrm{MgSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O}, \mathrm{Ba}(\mathrm{OH})_{2} \cdot 8 \mathrm{H}_{2} \mathrm{O},$ and $\mathrm{CoCl}_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O}$ .

Lindsey Smaka

Numerade Educator

Problem 82

Apply Explain how the hydrate in Figure 10.17 might be used as a means of roughly determining the probability of rain.

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 83

What is the numerical value of Avogadro’s number?

Himanshu Garg

Numerade Educator

Problem 84

How many atoms of potassium does 1 mol of potassium contain?

Prashant Bana

Numerade Educator

Problem 85

Compare a mole of Ag-108 and a mole of Pt-195 using atoms, protons, electrons, and neutrons.

Dr. Satish Ingale

Dr. Satish Ingale

Numerade Educator

Problem 86

Why is the mole an important unit to chemists?

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 87

Currency Examine the information in Table 10.2 and explain how rolls used to count pennies and dimes are similar to moles.

Himanshu Garg

Numerade Educator

Problem 88

Explain how Avogadro’s number is used as a conversion factor.

Himanshu Garg

Numerade Educator

Problem 89

Conversion Design a flowchart that could be used to help convert particles to moles or moles to particles.

Himanshu Garg

Numerade Educator

Problem 90

Determine the number of representative particles in each substance
a. 0.250 mol of silver
b. $8.56 \times 10^{-3}$ mol of sodium chloride
c. 35.3 mol of carbon dioxide
d. 0.425 mol of nitrogen $\left(\mathrm{N}_{2}\right)$

Himanshu Garg

Numerade Educator

Problem 91

Determine the number of representative particles in each substance.
a. 4.45 $\mathrm{mol}$ of $\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}$
b. 0.250 $\mathrm{mol}$ of $\mathrm{KNO}_{3}$
c. 2.24 $\mathrm{mol}$ of $\mathrm{H}_{2}$
d. 9.56 $\mathrm{mol}$ of $\mathrm{Zn}$

Himanshu Garg

Numerade Educator

Problem 92

How many molecules are contained in each compound?
a. 1.35 mol of carbon disulfide (CS_{2} )
b. 0.254 mol of diarsenic trioxide $\left(\mathrm{As}_{2} \mathrm{O}_{3}\right)$
c. 1.25 mol of water
d. 150.0 mol of $\mathrm{HCl}$

Ronald Prasad

Numerade Educator

Problem 93

Determine the number of moles in each substance.
a. $3.25 \times 10^{20}$ atoms of lead
b. $4.96 \times 10^{24}$ molecules of glucose
c. $1.56 \times 10^{23}$ formula units of sodium hydroxide
d. $1.25 \times 10^{25}$ copper (II) ions

Himanshu Garg

Numerade Educator

Problem 94

Perform the following conversions.
a. $1.51 \times 10^{15}$ atoms of Si to mol of Si
b. $4.25 \times 10^{-2}$ mol of $\mathrm{H}_{2} \mathrm{SO}_{4}$ to molecules of $\mathrm{H}_{2} \mathrm{SO}_{4}$
c. $8.95 \times 10^{25}$ molecules of $\mathrm{CCl}_{4}$ to mol of $\mathrm{CCl}_{4}$
d. 5.90 $\mathrm{mol}$ of Ca to atoms of Ca

Himanshu Garg

Numerade Educator

Problem 95

How many moles contain the given quantity?
a. $1.25 \times 10^{15}$ molecules of carbon dioxide
b. $3.59 \times 10^{21}$ formula units of sodium nitrate
c. $2.89 \times 10^{27}$ formula units of calcium carbonate

Himanshu Garg

Numerade Educator

Problem 96

RDA of Selenium The recommended daily allowance $(\mathrm{RDA})$ of selenium in your diet is $8.87 \times 10^{-4} \mathrm{mol}$ . How many atoms of selenium is this?

Stephen Pulliam

Stephen Pulliam

Numerade Educator

Problem 97

The two solutions shown in Figure 10.19 are mixed. What is the total number of metal ions in the mixture

Ali Mcdillon

Numerade Educator

Problem 98

Jewelry A bracelet containing 0.200 mol metal atoms is 75% gold. How many particles of gold atoms are in the bracelet?

Himanshu Garg

Numerade Educator

Problem 99

Snowflakes A snowflake contains $1.9 \times 10^{18}$ molecules of water. How many moles of water does it contain?

Ricajoy Montero

Ricajoy Montero

Numerade Educator

Problem 100

If you could count two atoms every second, how long would it take you to count a mole of atoms? Assume that you counted continually for 24 hours every day. How does the time you calculated compare with the age of Earth, which is estimated to be $4.5 \times 10^{9}$ years old?

Himanshu Garg

Numerade Educator

Problem 101

Chlorophyll The green color of leaves is due to the presence of chlorophyll, $\mathrm{C}_{55} \mathrm{H}_{72} \mathrm{O}_{5} \mathrm{N}_{4} \mathrm{Mg}$ . A fresh leaf was found to have $1.5 \times 10^{-5} \mathrm{mol}$ of chlorophyll per $\mathrm{cm}^{2} .$ How many chlorophyll molecules are in 1 $\mathrm{cm}^{2} ?$

Ali Mcdillon

Numerade Educator

Problem 102

Explain the difference between atomic mass (amu) and molar mass (g).

David Collins

Numerade Educator

Problem 103

Which contains more atoms, a mole of silver atoms or a mole of gold atoms? Explain your answer

Ricajoy Montero

Ricajoy Montero

Numerade Educator

Problem 104

Which has more mass, a mole of potassium or a mole of sodium? Explain your answer.

Rithvik Manne

Numerade Educator

Problem 105

Explain how you would convert from number of atoms of a specific element to its mass.

Ricajoy Montero

Ricajoy Montero

Numerade Educator

Problem 106

Discuss the relationships that exist between the mole, molar mass, and Avogadro’s number.

Himanshu Garg

Numerade Educator

Problem 107

Barbed Wire Barbed wire is often made of steel, which is primarily iron, and coated with zinc. Compare the number of particles and the mass of 1 mol of each.

Ali Mcdillon

Numerade Educator

Problem 108

Calculate the mass of each element.
a. 5.22 mol of He
b. 0.0455 mol of Ni
c. 2.22 mol of Ti
d. 0.00566 mol of Ge

Himanshu Garg

Numerade Educator

Problem 109

Perform the following conversions.
a. 3.50 mol of Li to g of Li
b. 7.65 g of Co to mol of Co
c. 5.62 g of Kr to mol of Kr
d. 0.0550 mol of As to g of As

David Collins

Numerade Educator

Problem 110

Determine the mass in grams of each element.
a. $1.33 \times 10^{22} \mathrm{mol}$ of $\mathrm{Sb}$
b. $4.75 \times 10^{14} \mathrm{mol}$ of $\mathrm{Pt}$
c. $1.22 \times 10^{23} \mathrm{mol}$ of Ag
d. $9.85 \times 10^{24} \mathrm{mol}$ of Cr

Himanshu Garg

Numerade Educator

Problem 111

Complete Table 10.3.

Himanshu Garg

Numerade Educator

Problem 112

Convert each to mass in grams.
a. $4.22 \times 10^{15}$ atoms U
b. $8.65 \times 10^{25}$ atoms $\mathrm{H}$
c. $1.25 \times 10^{22}$ atoms $\mathrm{O}$
d. $4.44 \times 10^{23}$ atoms $\mathrm{Pb}$

Himanshu Garg

Numerade Educator

Problem 113

Calculate the number of atoms in each element.
a. 25.8 g of Hg
b. 0.0340 g of Zn
c. 150 g of Ar
d. 0.124 g of Mg

Himanshu Garg

Numerade Educator

Problem 114

Arrange from least to most in moles: $3.00 \times 10^{24}$ atoms Ne, 4.25 mole $\mathrm{Ar}, 2.69 \times 10^{24}$ atoms $\mathrm{Xe}, 65.96 \mathrm{g} \mathrm{Kr}$ .

David Collins

Numerade Educator

Problem 115

Balance Precision A sensitive electronic balance can detect masses of $1 \times 10^{-8}$ g. How many atoms of silver would be in a sample having this mass?

Dr. Satish Ingale

Dr. Satish Ingale

Numerade Educator

Problem 116

A sample of a compound contains 3.86 g of sulfur and 4.08 g of vanadium. How many atoms of sulfur and vanadium does the compound contain?

Nicole Bylsma

Numerade Educator

Problem 117

Which has more atoms, 10.0 g of C or 10.0 g of Ca? How many atoms does each have?

Ali Mcdillon

Numerade Educator

Problem 118

Which has more atoms, 10.0 mol of C or 10.0 mol of Ca? How many atoms does each have?

Rithvik Manne

Numerade Educator

Problem 119

A mixture contains 0.250 mol of Fe and 1.20 g of C. What is the total number of atoms in the mixture?

Jennifer Hudspeth

Jennifer Hudspeth

Numerade Educator

Problem 120

Respiration Air contains several gases. When resting, every breath you take contains approximately 0.600 g of air. If argon makes up 0.934% of the air, calculate the number of argon atoms inhaled with each breath.

Himanshu Garg

Numerade Educator

Problem 121

What information is provided by the formula for potassium chromate $\left(\mathrm{K}_{2} \mathrm{CrO}_{4}\right) ?$

Himanshu Garg

Numerade Educator

Problem 122

In the formula for sodium phosphate $\left(\mathrm{Na}_{3} \mathrm{PO}_{4}\right),$ how many moles of sodium are represented? How many moles of phosphorus? How many moles of oxygen?

Himanshu Garg

Numerade Educator

Problem 123

Explain how you determine the molar mass of a compound.

Ricajoy Montero

Ricajoy Montero

Numerade Educator

Problem 124

Insect Repellent Many insect repellents use DEET as the active ingredient. DEET was patented in 1946 and is effective against many biting insects. What must you know to determine the molar mass of DEET?

Himanshu Garg

Numerade Educator

Problem 125

Why can molar mass be used as a conversion factor?

Ali Mcdillon

Numerade Educator

Problem 126

List three conversion factors used in molar conversions.

Himanshu Garg

Numerade Educator

Problem 127

Which of these contains the most moles of carbon atoms per mole of the compound ascorbic acid $\left(\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{6}\right)$ glycerin $\left(\mathrm{C}_{3} \mathrm{H}_{8} \mathrm{O}_{3}\right),$ or vanillin $\left(\mathrm{C}_{8} \mathrm{H}_{8} \mathrm{O}_{3}\right) ?$ Explain.

Ali Mcdillon

Numerade Educator

Problem 128

How many moles of oxygen atoms are contained in each compound?
a. 2.50 mol of KMnO $_{4}$
b. 45.9 mol of $\mathrm{CO}_{2}$
c. $1.25 \times 10^{-2}$ mol of $\mathrm{CuSO}_{4} \cdot 5 \mathrm{H}_{2} \mathrm{O}$

Himanshu Garg

Numerade Educator

Problem 129

How many carbon tetrachloride $\left(\mathrm{CCl}_{4}\right)$ molecules are in 3.00 $\mathrm{mol}$ of $\mathrm{CCl}_{4} ?$ How many carbon atoms? How many chlorine atoms? How many total atoms?

Ali Mcdillon

Numerade Educator

Problem 130

The graph in Figure 10.20 shows the numbers of atoms of each element in a compound. What is the compound’s formula? What is its molar mass?

Himanshu Garg

Numerade Educator

Problem 131

Determine the molar mass of each compound.
a. nitric acid $\left(\mathrm{HNO}_{3}\right)$
b. ammonium nitrate $\left(\mathrm{NH}_{4} \mathrm{NO}_{3}\right)$
c. zinc oxide $(\mathrm{ZnO})$
d. cobalt chloride $\left(\mathrm{CoCl}_{2}\right)$

Ali Mcdillon

Numerade Educator

Problem 132

Garlic Determine the molar mass of allyl sulfide, the compound responsible for the smell of garlic. The chemical formula of allyl sulfide is $\left(\mathrm{C}_{3} \mathrm{H}_{5}\right)_{2} \mathrm{S}$ .

Himanshu Garg

Numerade Educator

Problem 133

How many moles are in 100.0 g of each compound?
a. dinitrogen oxide$\left(\mathrm{N}_{2} \mathrm{O}\right)$
b. methanol $\left(\mathrm{CH}_{3} \mathrm{OH}\right)$

Ali Mcdillon

Numerade Educator

Problem 134

What is the mass of each compound?
a. $4.50 \times 10^{-2}$ mol of $\mathrm{CuCl}_{2}$
b. $1.25 \times 10^{2} \mathrm{mol}$ of $\mathrm{Ca}(\mathrm{OH})_{2}$

Rithvik Manne

Numerade Educator

Problem 135

Acne Benzoyl peroxide $\left(\mathrm{C}_{14} \mathrm{H}_{10} \mathrm{O}_{4}\right)$ is a substance used as an acne medicine. What is the mass in grams of $3.50 \times 10^{-2} \mathrm{mol} \mathrm{C}_{14} \mathrm{H}_{10} \mathrm{O}_{4}$ ?

Ali Mcdillon

Numerade Educator

Problem 136

Glass Etching Hydrofluoric acid is a substance used to etch glass. Determine the mass of $4.95 \times 10^{25} \mathrm{HF}$ molecules.

Rithvik Manne

Numerade Educator

Problem 137

What is the mass of a mole of electrons if one electron has a mass of $9.11 \times 10^{-28} \mathrm{g}$ ?

Ali Mcdillon

Numerade Educator

Problem 138

How many moles of ions are in each compound?
a. 0.0200 g of AgNO $_{3}$
b. 0.100 mol of $\mathrm{K}_{2} \mathrm{CrO}_{4}$
c. 0.500 $\mathrm{g}$ of $\mathrm{Ba}(\mathrm{OH})_{2}$
d. $1.00 \times 10^{-9} \mathrm{mol}$ of $\mathrm{Na}_{2} \mathrm{CO}_{3}$

Himanshu Garg

Numerade Educator

Problem 139

How many formula units are present in 500.0 g of lead(II) chloride?

Ali Mcdillon

Numerade Educator

Problem 140

Determine the number of atoms in 3.50 $\mathrm{g}$ of gold.

Rithvik Manne

Numerade Educator

Problem 141

Calculate the mass of $3.62 \times 10^{24}$ molecules of glucose $\left(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\right)$

Ali Mcdillon

Numerade Educator

Problem 142

Determine the number of molecules of ethanol $\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)$ in 47.0 $\mathrm{g} .$

Rithvik Manne

Numerade Educator

Problem 143

What mass of iron(III) chloride contains $2.35 \times 10^{23}$ chloride ions?

Ali Mcdillon

Numerade Educator

Problem 144

How many moles of iron can be recovered from 100.0 $\mathrm{kg}$ of $\mathrm{Fe}_{3} \mathrm{O}_{4} ?$

Rithvik Manne

Numerade Educator

Problem 145

Cooking A common cooking vinegar is 5.0$\%$ acetic acid $\left(\mathrm{CH}_{3} \mathrm{COOH}\right) .$ How many molecules of acetic acid are present in 25.0 $\mathrm{g}$ of vinegar?

Ali Mcdillon

Numerade Educator

Problem 146

Calculate the moles of aluminum ions present in 250.0 $\mathrm{g}$ of aluminum oxide $\left(\mathrm{Al}_{2} \mathrm{O}_{3}\right)$

Rithvik Manne

Numerade Educator

Problem 147

Determine the number of chloride ions in 10.75 g of magnesium chloride.

Ali Mcdillon

Numerade Educator

Problem 148

Pain Relief Acetaminophen, a common aspirin substitute, has the formula $\mathrm{C}_{8} \mathrm{H}_{9} \mathrm{NO}_{2} .$ Determine the number of molecules of acetaminophen in a 500 -mg tablet.

Rithvik Manne

Numerade Educator

Problem 149

Calculate the number of sodium ions present in 25.0 g of sodium chloride.

Ali Mcdillon

Numerade Educator

Problem 150

Determine the number of oxygen atoms present in 25.0 g of carbon dioxide.

Rithvik Manne

Numerade Educator

Problem 151

Espresso There is $1.00 \times 10^{2} \mathrm{mg}$ of caffeine in a shot of espresso. The chemical formula of caffeine is $\mathrm{C}_{8} \mathrm{H}_{10} \mathrm{N}_{4} \mathrm{O}_{2}$ Determine the moles of each element present in the caffeine in one shot of espresso.

Ali Mcdillon

Numerade Educator

Problem 152

The density of lead (Pb) is 11.3 $\mathrm{g} / \mathrm{cm}^{3}$ . Calculate the volume of 1 $\mathrm{mol}$ of $\mathrm{Pb}$ .

Rithvik Manne

Numerade Educator

Problem 153

Explain what is meant by percent composition

Ali Mcdillon

Numerade Educator

Problem 154

What information must a chemist obtain in order to determine the empirical formula of an unknown compound?

David Collins

Numerade Educator

Problem 155

What information must a chemist have to determine the molecular formula for a compound?

Ali Mcdillon

Numerade Educator

Problem 156

What is the difference between an empirical formula and a molecular formula? Provide an example.

Rithvik Manne

Numerade Educator

Problem 157

When can the empirical formula be the same as the molecular formula?

Ali Mcdillon

Numerade Educator

Problem 158

Antibacterial Soap Triclosan is an antibacterial agent included in detergents, dish soaps, laundry soaps, deodorants, cosmetics, lotions, creams, toothpastes, and mouthwashes. The chemical formula for triclosan is $\mathrm{C}_{12} \mathrm{H}_{7} \mathrm{Cl}_{3} \mathrm{O}_{2}$ . What information did the chemist need to determine this formula?

Rithvik Manne

Numerade Educator

Problem 159

Which of the following formulas-NO, $\mathrm{N}_{2} \mathrm{O}, \mathrm{NO}_{2}, \mathrm{N}_{2} \mathrm{O}_{4}$ and $\mathrm{N}_{2} \mathrm{O}_{5}-$ represent the empirical and molecular formulas of the same compound? Explain your answer.

Himanshu Garg

Numerade Educator

Problem 160

Do all pure samples of a given compound have the same percent composition? Explain.

Rithvik Manne

Numerade Educator

Problem 161

The circle graph in Figure 10.21 shows the percent composition of a compound containing barium, carbon, and oxygen. What is the empirical formula of this compound?

Ali Mcdillon

Numerade Educator

Problem 162

Iron Three naturally occurring iron compounds are pyrite $\left(\mathrm{FeS}_{2}\right),$ hematite $\left(\mathrm{Fe}_{2} \mathrm{O}_{3}\right),$ and siderite $\left(\mathrm{FeCO}_{3}\right)$ Which contains the greatest percentage of iron?

Rithvik Manne

Numerade Educator

Problem 163

Express the composition of each compound as the mass percent of its elements (percent composition).
a. sucrose $\left(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\right)$
b. aluminum sulfate $\left(\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}\right)$
c. magnetite $\left(\mathrm{Fe}_{3} \mathrm{O}_{4}\right)$

Himanshu Garg

Numerade Educator

Problem 164

Vitamin $D_{3}$ Your body's ability to absorb calcium is aided by vitamin $D_{3} .$ Chemical analysis of vitamin $D_{3}$ yields the data shown in Figure $10.22 .$ What$$
\text { Both empirical and molecular formulas for this compound is } C_{27} H_{44} O
$$ are the empirical and molecular formulas for vitamin $D_{3} ?$

David Collins

Numerade Educator

Problem 165

When a 35.07-g sample of phosphorus reacts with oxygen, a 71.00-g sample of phosphorus oxide is formed. What is the percent composition of the compound? What is the empirical formula for this compound?

Ali Mcdillon

Numerade Educator

Problem 166

Cholesterol Heart disease is linked to high blood cholesterol levels. What is the percent composition of the elements in a molecule of cholesterol $\left(\mathrm{C}_{27} \mathrm{H}_{45} \mathrm{OH}\right)$ ?

Himanshu Garg

Numerade Educator

Problem 167

Determine the empirical formula for each compound.
a. ethylene $\left(\mathrm{C}_{2} \mathrm{H}_{4}\right)$
b. ascorbic acid $\left(\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{6}\right)$
c. naphthalene $\left(\mathrm{C}_{10} \mathrm{H}_{8}\right)$

Himanshu Garg

Numerade Educator

Problem 168

Caffeine The stimulant effect of coffee is due to caffeine, $\mathrm{C}_{8} \mathrm{H}_{10} \mathrm{N}_{4} \mathrm{O}_{2}$ . Calculate the molar mass of caffeine. Determine its percent composition.

Rithvik Manne

Numerade Educator

Problem 169

Which titanium-containing mineral, rutile $\left(\mathrm{TiO}_{2}\right)$ or ilmenite (FeTiO $_{3} ),$ has the larger percentage of titanium?

Ali Mcdillon

Numerade Educator

Problem 170

Vitamin E Many plants contain vitamin $\mathrm{E}\left(\mathrm{C}_{29} \mathrm{H}_{50} \mathrm{O}_{2}\right)$ a substance that some think slows the aging process in humans. What is the percent composition of vitamin E?

Rithvik Manne

Numerade Educator

Problem 171

Artificial Sweetener Determine the percent composition of aspartame $\left(\mathrm{C}_{14} \mathrm{H}_{18} \mathrm{N}_{2} \mathrm{O}_{5}\right),$ an artificial sweetener.

Pronoy Sinha

Numerade Educator

Problem 172

MSG Monosodium glutamate, known as MSG, is sometimes added to food to enhance flavor. Analysis determined this compound to be 35.5% C, 4.77% H, 8.29% N, 13.6% Na, and 37.9% O. What is its empirical formula?

Himanshu Garg

Numerade Educator

Problem 173

What is the empirical formula of a compound that contains 10.52 g Ni, 4.38 g C, and 5.10 g N?

Himanshu Garg

Numerade Educator

Problem 174

Patina The Statue of Liberty has turned green because of the formation of a patina. Two copper compounds, $\mathrm{Cu}_{3}(\mathrm{OH})_{4} \mathrm{SO}_{4}$ and $\mathrm{Cu}_{4}(\mathrm{OH})_{6} \mathrm{SO}_{4},$ form this patina. Find the mass percentage of copper in each compound.

Rithvik Manne

Numerade Educator

Problem 175

What is a hydrated compound? Use an example to illustrate your answer.

Ali Mcdillon

Numerade Educator

Problem 176

Explain how hydrates are named.

David Collins

Numerade Educator

Problem 177

Desiccants Why are certain electronic devices transported with desiccants?

Ali Mcdillon

Numerade Educator

Problem 178

In a laboratory setting, how would you determine if a compound was a hydrate?

David Collins

Numerade Educator

Problem 179

Write the formula for the following hydrates.
a. nickel(II) chloride hexahydrate
b. cobalt(II) chloride hexahydrate
c. magnesium carbonate pentahydrate
d. sodium sulfate decahydrate

Himanshu Garg

Numerade Educator

Problem 180

Determine the mass percent of anhydrous sodium carbonate $\left(\mathrm{Na}_{2} \mathrm{CO}_{3}\right)$ and water in sodium carbonate decahydrate $\left(\mathrm{Na}_{2} \mathrm{CO}_{3} \cdot 10 \mathrm{H}_{2} \mathrm{O}\right)$

David Collins

Numerade Educator

Problem 181

Table 10.4 shows data from an experiment to determine the formulas of hydrated barium chloride. Determine the formula for the hydrate and its name.

Ali Mcdillon

Numerade Educator

Problem 182

Chromium(III) nitrate forms a hydrate that is 40.50% water by mass. What is its chemical formula?

Himanshu Garg

Numerade Educator

Problem 183

Determine the percent composition of $\mathrm{MgCO}_{3} \cdot 5 \mathrm{H}_{2} \mathrm{O}$ and draw a pie graph to represent the hydrate.

Ali Mcdillon

Numerade Educator

Problem 184

What is the formula and name of a hydrate that is 85.3% barium chloride and 14.7% water?

Nicole Powell

Numerade Educator

Problem 185

Gypsum is hydrated calcium sulfate. A 4.89-g sample of this hydrate was heated. After the water was removed, 3.87 g anhydrous calcium sulfate remained. Determine the formula for this hydrate and name the compound.

Ali Mcdillon

Numerade Educator

Problem 186

A 1.628-g sample of a hydrate of magnesium iodide is heated until its mass is reduced to 1.072 g and all water has been removed. What is the formula of the hydrate?

Vasu Makani

Numerade Educator

Problem 187

Borax Hydrated sodium tetraborate $\left(\mathrm{Na}_{2} \mathrm{B}_{4} \mathrm{O}_{7} \cdot \mathrm{xH}_{2} \mathrm{O}\right)$ is commonly called borax. Chemical analysis indicates that this hydrate is 52.8$\%$ sodium tetraborate and 47.2$\%$ water. Determine the formula and name the hydrate.

Himanshu Garg

Numerade Educator

Problem 188

Rank samples $A-D$ from least number of atoms to greatest number of atoms. A: 1.0 $\mathrm{mol}$ of $\mathrm{H}_{2} ; \mathrm{B} : 0.75 \mathrm{mol}$ of $\mathrm{H}_{2} \mathrm{O} ; \mathrm{C} : 1.5 \mathrm{mol}$ of $\mathrm{NaCl} ; \mathrm{D} : 0.50 \mathrm{mol}$ of $\mathrm{Ag}_{2} \mathrm{S}$

Himanshu Garg

Numerade Educator

Problem 189

The graph in Figure 10.23 shows the percent composition of a compound containing carbon, hydrogen, oxygen, and nitrogen. How many grams of each element are present in 100 g of the compound?

Ali Mcdillon

Numerade Educator

Problem 190

How many grams of $\mathrm{CoCl}_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O}$ must you measure out in a container to have exactly Avogadro's number of particles?

Rithvik Manne

Numerade Educator

Problem 191

One atom of an unknown element has a mass of $6.66 \times 10^{-23} \mathrm{g} .$ What is the identity of this element?

Ronald Prasad

Numerade Educator

Problem 192

Skunks Analysis of skunk spray yields a molecule with 44.77% C, 7.46% H and 47.76% S. What is the chemical formula for this molecule found in the spray from skunks that scientists think is partly responsible for the strong odor?

Himanshu Garg

Numerade Educator

Problem 193

How many moles are present in 1.00 g of each compound?
a. L-tryptophan $\left(\mathrm{C}_{11} \mathrm{H}_{12} \mathrm{N}_{2} \mathrm{O}_{2}\right),$ an essential amino acid
b. magnesium sulfate heptahydrate, also known as Epsom salts
c. propane $\left(\mathrm{C}_{5} \mathrm{H}_{8}\right),$ a fuel

Himanshu Garg

Numerade Educator

Problem 194

A compound contains 6.0 g of carbon and 1.0 g of hydrogen, and has a molar mass of 42.0 g/mol. What are the compound’s percent composition, empirical formula, and molecular formula?

Chareen Guzman

Numerade Educator

Problem 195

Which of these compounds has the greatest percent of oxygen by mass: TiO $_{2}, \mathrm{Fe}_{2} \mathrm{O}_{3},$ or $\mathrm{Al}_{2} \mathrm{O}_{3} ?$

Ali Mcdillon

Numerade Educator

Problem 196

Mothballs Naphthalene, commonly found in mothballs, is composed of 93.7% carbon and 6.3% hydrogen. The molar mass of naphthalene is 128 g/mol. Determine the empirical and molecular formulas for naphthalene.

Himanshu Garg

Numerade Educator

Problem 197

Which of these molecular formulas are also empirical formulas: ethyl ether $\left(\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O}\right),$ aspirin $\left(\mathrm{C}_{9} \mathrm{H}_{8} \mathrm{O}_{4}\right),$ butyl dichloride $\left(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{O}_{2}\right),$ glucose $\left(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\right) ?$

Ali Mcdillon

Numerade Educator

Problem 198

Apply Concepts A mining company has two possible sources of copper: chalcopyrite (CuFeS $_{2} )$ and chalcocite $\left(\mathrm{Cu}_{2} \mathrm{S}\right) .$ If the mining conditions and the extraction of copper from the ore were identical for each of the ores, which ore would yield the greater quantity of copper? Explain your answer.

Megan Lucas

Numerade Educator

Problem 199

Analyze and Conclude On a field trip, students collected rock samples. Analysis of the rocks revealed that two of the rock samples contained lead and sulfur. Table 10.5 shows the percent lead and sulfur in each of the rocks. Determine the molecular formula of each rock. What can the students conclude about the rock samples?

Ali Mcdillon

Numerade Educator

Problem 200

Graph A YAG, or yttrium aluminum garnet $\left(\mathrm{Y}_{3} \mathrm{Al}_{5} \mathrm{O}_{12}\right),$ is a synthetic gemstone which has no counterpart in nature. Design a bar graph to indicate the moles of each element present in a 5.67 carat yttrium aluminum garnet. ( carat $=0.20 \mathrm{g} )$

Himanshu Garg

Numerade Educator

Problem 201

Assess The structure of the TNT molecule is shown in Figure 10.24. Critique the statement “Trinitrotoluene, TNT, contains 21 atoms per mole.” What is correct about the statement and what is incorrect? Rewrite the statement

Himanshu Garg

Numerade Educator

Problem 202

Design an Experiment Design an experiment that can be used to determine the amount of water in alum $\left(\mathrm{KAl}\left(\mathrm{SO}_{4}\right)_{2} \cdot x \mathrm{H}_{2} \mathrm{O}\right)$

David Collins

Numerade Educator

Problem 203

Design a concept map that illustrates the mole concept. Include the terms moles, Avogadro’s number, molar mass, number of particles, percent composition, empirical formula, and molecular formula

Himanshu Garg

Numerade Educator

Problem 204

Two different compounds are composed of Elements $\mathrm{X}$ and $\mathrm{Y}$ . The formulas of the compounds are $\mathrm{X}_{2} \mathrm{Y}_{3}$ and $\mathrm{XY}$ . A 0.25 mol sample of $\mathrm{XY}$ has a mass of $17.96 \mathrm{g},$ and a 0.25 mol sample of $\mathrm{X}_{2} \mathrm{Y}_{3}$ has a mass of 39.92 $\mathrm{g}$ .
a. What are the atomic masses of elements $\mathrm{X}$ and $\mathrm{Y}$ ?
b. What are the formulas for the compounds?

Himanshu Garg

Numerade Educator

Problem 205

Express each answer with the correct number of significant figures. (Chapter 2)
a. $18.23-456.7$
b. $4.233 \div 0.0131$
c. $(82.44 \times 4.92)+0.125$

Himanshu Garg

Numerade Educator

Problem 206

Making Candy A recipe for pralines calls for the candy mixture to be heated until it reaches the "soft ball" stage, at about $236^{\circ} \mathrm{F}$ . Can a Celsius thermometer with a range of $-10$ to
$110^{\circ} \mathrm{C}$ be used to determine when the "softball" stage is reached? (Chapter 2)

Himanshu Garg

Numerade Educator

Problem 207

Contrast atomic number and mass number. Compare these numbers for isotopes of an element. (Chapter 4)

Ali Mcdillon

Numerade Educator

Problem 208

Describe the phenomenon in Figure 10.25. Explain why the electrons are not bound to the nuclei. (Chapter 5)

David Collins

Numerade Educator

Problem 209

Given the elements Ar, Cs, Br, and Ra, identify those that form positive ions. Explain your answer. (Chapter 7)

Ali Mcdillon

Numerade Educator

Problem 210

Write the formula and name the compound formed when each pair of elements combine. (Chapter 7)
a. barium and chlorine
b. aluminum and selenium
c. calcium and phosphorus

Himanshu Garg

Numerade Educator

Problem 211

Write balanced equations for each reaction. (Chapter 9)
a. Magnesium metal and water combine to form solid magnesium hydroxide and hydrogen gas.
b. Dinitrogen tetroxide gas decomposes into nitrogen dioxide gas.
c. Aqueous solutions of sulfuric acid and potassium hydroxide undergo a double-replacement reaction.

Himanshu Garg

Numerade Educator

Problem 212

Natural Gas Natural gas hydrates are chemical compounds known as clathrate hydrates. Research natural gas hydrates and prepare an educational pamphlet for consumers. The pamphlet should discuss the composition and structure of the compounds, the location of the hydrates, their importance to consumers, and the environmental impact of using the hydrates.

Himanshu Garg

Numerade Educator

Problem 213

Avogadro Research and report on the life of Italian chemist Amedeo Avogadro (1776–1856) and how his work led scientists to determine the number of particles in a mole.

Himanshu Garg

Numerade Educator

Problem 214

Luminol Crime-scene investigators use luminol to visualize blood residue. Research luminol and determine its chemical formula and percent composition.

Himanshu Garg

Numerade Educator

Problem 215

Hydrazine contains 87.45% nitrogen and 12.55% hydrogen, and has a molar mass of 32.04 g/mol. Determine hydrazine’s molecular formula. Record the molecular formula in Table 10.6.

Abdel Osman

Numerade Educator

Problem 216

Complete Table 10.6 by calculating the number of moles, mass in kilograms, or molecules for each propellant. Give all answers to three significant figures.

David Collins

Numerade Educator