Chemistry: The Molecular Nature of Matter

Neil D. Jespersen, James E. Brady, Alison Hyslop

Chapter 3 The Mole and Stoichiometry - all with Video Answers

Educators

+ 8 more educators

Chapter Questions

00:18

Problem 1

What is the definition of the mole?

David Collins

Numerade Educator

04:46

Problem 2

Why are moles used, when all stoichiometry problems could be done using only atomic mass units?

Dr. Satish Ingale

Numerade Educator

06:12

Problem 3

Which contains more molecules: $2.5 \mathrm{~mol}$ of $\mathrm{H}_{2} \mathrm{O}$ or $2.5 \mathrm{~mol}$ of $\mathrm{H}_{2}$ ? Which contains more atoms? Which weighs more?

Dr. Satish Ingale

Numerade Educator

03:20

Write the following as balanced chemical equations.
(a) Calcium hydroxide reacts with hydrogen chloride to form calcium chloride and water.
(b) Silver nitrate and calcium chloride react to form calcium nitrate and silver chloride.
(c) Lead(II) nitrate reacts with sodium sulfate to form lead(II) sulfate and sodium nitrate.
(d) Iron(III) oxide and carbon react to form iron and carbon dioxide.

Dr. Satish Ingale

Numerade Educator

02:49

Problem 4

How would Avogadro's number change if the atomic mass unit were to be redefined as $2 \times 10^{-27} \mathrm{~kg}$, exactly?

Dr. Satish Ingale

Numerade Educator

03:15

Problem 4

Write the following as balanced chemical equations.
(a) Sulfur dioxide reacts with oxygen to form sulfur trioxide.
(b) Sodium bicarbonate and sulfuric acid react to form sodium sulfate, water, and carbon dioxide.
(c) Tetraphosphorous decaoxide and water react together and form phosphoric acid.
(d) Butane reacts with oxygen to form carbon dioxide and water.

Dr. Satish Ingale

Numerade Educator

01:59

Problem 5

What information is required to convert grams of a substance into molecules of that same substance?

Dr. Satish Ingale

Numerade Educator

04:57

Problem 6

Using atomic mass units, how would you estimate the number of atoms in a gram of iron?

Dr. Satish Ingale

Numerade Educator

04:08

Problem 7

How many moles of iron atoms are in one mole of $\mathrm{Fe}_{2} \mathrm{O}_{3}$ ? How many iron atoms are in one mole of $\mathrm{Fe}_{2} \mathrm{O}_{3}$ ?

Dr. Satish Ingale

Numerade Educator

09:28

Problem 8

Write all the mole-to-mole conversion factors that can be written based on the following chemical formulas:
(a) $\mathrm{SO}_{2}$,
(b) $\mathrm{As}_{2} \mathrm{O}_{3}$
(c) $\mathrm{K}_{2} \mathrm{SO}_{4}$
(d) $\mathrm{Na}_{2} \mathrm{HPO}_{4}$

Dr. Satish Ingale

Numerade Educator

02:58

Problem 9

What information is required to convert grams of a substance into moles of that same substance?

Dr. Satish Ingale

Numerade Educator

02:24

Problem 10

Why is the expression "1.0 mol of oxygen" ambiguous? Why doesn't a similar ambiguity exist in the expression "64 g of oxygen?"

Dr. Satish Ingale

Numerade Educator

02:49

Problem 11

The atomic mass of aluminum is 26.98 . What specific conversion factors does this value make available for relating a mass of aluminum (in grams) and a quantity of aluminum given in moles?

Dr. Satish Ingale

Numerade Educator

02:35

Problem 12

If you are given the mass of two elements and the mass of the compound for a sample, how can you determine if there is another element in the compound?

Dr. Satish Ingale

Numerade Educator

07:14

Problem 13

How can percentage composition be used to identify a compound?

Dr. Satish Ingale

Numerade Educator

02:34

Problem 14

In general, what fundamental information, obtained from experimental measurements, is required to calculate the empirical formula of a compound?

Dr. Satish Ingale

Numerade Educator

00:52

Problem 15

Why can percentage composition be used to determine empirical formula, but not molecular formula?

Dr. Satish Ingale

Numerade Educator

07:33

Problem 16

Why can percentage composition be used to determine empirical formula, but not molecular formula?

Dr. Satish Ingale

Numerade Educator

02:34

Problem 17

Under what circumstances can we change, or assign, subscripts in a chemical formula?

Dr. Satish Ingale

Numerade Educator

03:16

Problem 18

How many distinct empirical formulas are shown by the following models for compounds formed between elements $A$ and $B$ ? Explain. (Element $A$ is represented by a black sphere and element $B$ by a light gray sphere.)

Dr. Satish Ingale

Numerade Educator

03:32

Problem 19

When balancing a chemical reaction, what numbers can be changed? When balancing chemical equations which scientific law is being used?

Dr. Satish Ingale

Numerade Educator

05:06

Problem 20

When given the unbalanced equation
$$
\mathrm{Na}(s)+\mathrm{Cl}_{2}(g) \longrightarrow \mathrm{NaCl}(s)
$$
and asked to balance it, student $\mathrm{A}$ wrote
$$
\mathrm{Na}(s)+\mathrm{Cl}_{2}(g) \longrightarrow \mathrm{NaCl}_{2}(s)
$$
and student $\mathrm{B}$ wrote
$$
2 \mathrm{Na}(s)+\mathrm{Cl}_{2}(g) \longrightarrow 2 \mathrm{NaCl}(s)
$$
Both equations are balanced, but which student is correct? Explain why the other student's answer is incorrect.

Dr. Satish Ingale

Numerade Educator

06:15

Problem 21

Give a step-by-step procedure for estimating the number of grams of $A$ required to completely react with 10 moles of $B$, given the following information:
$A$ and $B$ react to form $A_{5} B_{2}$
$A$ has a molecular mass of $100.0 . B$ has a molecular mass of 200.0

There are $6.02 \times 10^{23}$ molecules of $A$ in a mole of $A$.
Which of these pieces of information weren't needed?

Dr. Satish Ingale

Numerade Educator

01:49

Problem 22

If two substances react completely in a 1 -to-1 ratio both by mass and by moles, what must be true about these substances?

Dr. Satish Ingale

Numerade Educator

02:21

Problem 23

What information is required to determine how many grams of sulfur would react with a gram of arsenic?

Dr. Satish Ingale

Numerade Educator

02:56

Problem 24

A mixture of $0.020 \mathrm{~mol}$ of $\mathrm{Mg}$ and $0.020 \mathrm{~mol}$ of $\mathrm{Cl}_{2}$ reacted completely to form $\mathrm{MgCl}_{2}$ according to the equation
$$
\mathrm{Mg}+\mathrm{Cl}_{2} \longrightarrow \mathrm{MgCl}_{2}
$$
What information describes the stoichiometry of this reaction? What information gives the scale of the reaction?

Dr. Satish Ingale

Numerade Educator

01:59

Problem 25

In a report to a supervisor, a chemist described an experiment in the following way: " $0.0800 \mathrm{~mol}$ of $\mathrm{H}_{2} \mathrm{O}_{2}$ decomposed into $0.0800 \mathrm{~mol}$ of $\mathrm{H}_{2} \mathrm{O}$ and $0.0400 \mathrm{~mol}$ of $\mathrm{O}_{2}$." Express the chemistry and stoichiometry of this reaction by a conventional chemical equation.

Dr. Satish Ingale

Numerade Educator

10:05

Problem 26

On April $16,1947,$ in Texas City, Texas, two cargo ships, the Grandcamp and the High Flier, were each loaded with approximately 2000 tons of ammonium nitrate fertilizer. The Grandcamp caught fire and exploded, followed by the High Flier. More than 600 people were killed and one-third of the city was destroyed. Considering a much smaller mass, how would you count the number of $\mathrm{N}_{2}$ molecules that could be produced after the explosion of $1.00 \mathrm{~kg}$ of $\mathrm{NH}_{4} \mathrm{NO}_{3} ?$

Dr. Satish Ingale

Numerade Educator

04:32

Problem 27

What is a limiting reactant? And why does the limiting reactant determine how much product is formed?

Dr. Satish Ingale

Numerade Educator

04:10

Problem 28

Molecules containing $A$ and $B$ react to form $A B$ as shown below. Based on the equations and the contents of the boxes labeled "Initial," sketch for each reaction the molecular models of what is present after the reaction is over. (In both cases, the species $B$ exists as $B_{2}$. In reaction $1, A$ is monatomic; in reaction $2, A$ exists as diatomic molecules $A_{2}$.)

Dr. Satish Ingale

Numerade Educator

06:48

Problem 29

Explain why the actual yield is always less than the theoretical yield.

Dr. Satish Ingale

Numerade Educator

02:16

Problem 30

Is a $45 \%$ yield ever a good percentage yield? Why?

Dr. Satish Ingale

Numerade Educator

03:46

Problem 31

Determine the mass in grams of each of the following:
(a) $1.35 \mathrm{~mol} \mathrm{Fe}$
(c) $0.876 \mathrm{~mol} \mathrm{Ca}$
(b) $24.5 \mathrm{~mol} \mathrm{O}$

Dr. Satish Ingale

Numerade Educator

03:26

Problem 32

Determine the mass in grams of the following:
(a) $0.546 \mathrm{~mol} \mathrm{~S}$
(c) $8.11 \mathrm{~mol} \mathrm{Al}$
(b) $3.29 \mathrm{~mol} \mathrm{~N}$

Dr. Satish Ingale

Numerade Educator

14:41

Problem 33

Calculate the formula mass of each of the following to the maximum number of significant figures possible using the table of atomic masses inside the front cover
(a) $\mathrm{NaHCO}_{3}$
(d) potassium dichromate
(b) $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{CO}_{3}$
(e) aluminum sulfate
(c) $\mathrm{CuSO}_{4} \cdot 5 \mathrm{H}_{2} \mathrm{O}$

Dr. Satish Ingale

Numerade Educator

13:39

Problem 34

Calculate the formula mass of each of the following to the maximum number of significant figures possible using (a) the periodic table and (b) the table of atomic masses. Both tables are found inside the front cover.
(a) $\mathrm{Pb}\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{4}$
(d) calcium nitrate
(b) $\mathrm{Na}_{2} \mathrm{SO}_{4} \cdot 10 \mathrm{H}_{2} \mathrm{O}$
(e) magnesium phosphate
(c) $\mathrm{Fe}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]_{3}$

Dr. Satish Ingale

Numerade Educator

View

Problem 35

Calculate the mass in grams of the following.
(a) $1.25 \mathrm{~mol} \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}$
(b) $0.600 \mu \mathrm{mol} \mathrm{C}_{4} \mathrm{H}_{10}$
(c) $0.625 \mathrm{mmol}$ iron(III) nitrate
(d) 1.45 mol ammonium carbonate

Susan Hallstrom

Numerade Educator

04:59

Problem 36

What is the mass in grams of the following?
(a) $0.322 \mathrm{mmol} \mathrm{POCl}_{3}$
(b) $4.31 \times 10^{-3} \mathrm{~mol}\left(\mathrm{NH}_{4}\right)_{2} \mathrm{HPO}_{4}$
(c) 0.754 mol zinc chloride
(d) $0.194 \mu \mathrm{mol}$ potassium chlorate

Dr. Satish Ingale

Numerade Educator

04:48

Problem 37

Calculate the number of moles of each compound in the following samples.
(a) $1.56 \mathrm{ng} \mathrm{NH}_{3}$
(c) $21.5 \mathrm{~g}$ calcium carbonate
(b) $6.98 \mu \mathrm{g} \mathrm{Na}_{2} \mathrm{CrO}_{4}$
(d) $16.8 \mathrm{~g}$ strontium nitrate

Dr. Satish Ingale

Numerade Educator

04:08

Problem 38

Calculate the number of moles of each compound in the following samples.
(a) $4.29 \mathrm{~g} \mathrm{H}_{2} \mathrm{O}_{2}$
(c) $9.36 \mathrm{~g}$ calcium hydroxide
(b) $4.65 \mathrm{mg} \mathrm{NaAuCl}_{4}$
(d) $38.2 \mathrm{~kg}$ lead $(\mathrm{II})$ sulfate

Dr. Satish Ingale

Numerade Educator

01:48

Problem 39

How many moles of nickel are in $17.7 \mathrm{~g}$ of $\mathrm{Ni}$ ?

Dr. Satish Ingale

Numerade Educator

01:48

Problem 40

How many moles of chromium are in $85.7 \mathrm{~g}$ of $\mathrm{Cr}$ ?

Dr. Satish Ingale

Numerade Educator

03:00

Problem 41

How many moles of tantalum atoms correspond to $1.56 \times 10^{21}$ atoms of tantalum?

Dr. Satish Ingale

Numerade Educator

03:20

Problem 42

How many moles of iodine molecules correspond to $1.80 \times 10^{24}$ molecules of $\mathrm{I}_{2} ?$

Dr. Satish Ingale

Numerade Educator

03:45

Problem 43

A nanotechnology experiment requires $2.00 \times 10^{12}$ atoms of potassium. What is the mass of this sample?

Dr. Satish Ingale

Numerade Educator

View

Problem 44

What is the mass, in grams, of $4 \times 10^{17}$ atoms of gold present in one nanoparticle?

Ronald Prasad

Numerade Educator

02:07

Problem 45

How many atoms are in $6.00 \mathrm{~g}$ of carbon-12?

Dr. Satish Ingale

Numerade Educator

02:54

Problem 46

How many atoms are in $1.50 \mathrm{~mol}$ of carbon-12? How many grams does this much carbon-12 weigh?

Jennifer Hudspeth

Numerade Educator

01:41

Problem 47

Sucrose (table sugar) has the formula $\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11} .$ In this compound, what is the
(a) atom ratio of $\mathrm{C}$ to $\mathrm{H}$ ?
(c) atom ratio of $\mathrm{H}$ to $\mathrm{O}$ ?
(b) mole ratio of $\mathrm{C}$ to $\mathrm{O}$ ?
(d) mole ratio of $\mathrm{H}$ to $\mathrm{O}$ ?

Dr. Satish Ingale

Numerade Educator

01:28

Problem 48

Nail polish remover is usually the volatile liquid ethyl acetate, $\mathrm{CH}_{3} \mathrm{COOC}_{2} \mathrm{H}_{5} .$ In this compound, what is the
(a) atom ratio of $\mathrm{C}$ to $\mathrm{O}$ ?
(c) atom ratio of $\mathrm{C}$ to $\mathrm{H}$ ?
(b) mole ratio of $\mathrm{C}$ to $\mathrm{O}$ ?
(d) mole ratio of $\mathrm{C}$ to $\mathrm{H}$ ?

Dr. Satish Ingale

Numerade Educator

01:51

Problem 49

How many moles of $\mathrm{Bi}$ atoms are needed to combine with $1.58 \mathrm{~mol}$ of $\mathrm{O}$ atoms to make $\mathrm{Bi}_{2} \mathrm{O}_{3}$ ?

Dr. Satish Ingale

Numerade Educator

02:04

Problem 50

How many moles of vanadium atoms, $\mathrm{V},$ are needed to combine with 0.565 mol of $\mathrm{O}$ atoms to make vanadium pentoxide, $\mathrm{V}_{2} \mathrm{O}_{5} ?$

Dr. Satish Ingale

Numerade Educator

01:59

Problem 51

How many moles of $\mathrm{Cr}$ are in $2.16 \mathrm{~mol}$ of $\mathrm{Cr}_{2} \mathrm{O}_{3}$ ?

Dr. Satish Ingale

Numerade Educator

02:27

Problem 52

How many moles of $\mathrm{O}$ atoms are in $4.25 \mathrm{~mol}$ of calcium carbonate, $\mathrm{CaCO}_{3}$, the chief constituent of seashells?

Dr. Satish Ingale

Numerade Educator

05:04

Problem 53

Aluminum sulfate, $\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}$, is a compound used in sewage treatment plants to remove pollutants by causing them to precipitate.
(a) Construct a pair of conversion factors that relate moles of aluminum to moles of sulfur for this compound.
(b) Construct a pair of conversion factors that relate moles of sulfur to moles of $\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}$.
(c) How many moles of $\mathrm{Al}$ are in a sample of this compound if the sample also contains $0.900 \mathrm{~mol} \mathrm{~S} ?$
(d) How many moles of $S$ are in $1.16 \mathrm{~mol} \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}$ ?

Dr. Satish Ingale

Numerade Educator

06:22

Problem 54

Magnetite is a magnetic iron ore. Its formula is $\mathrm{Fe}_{3} \mathrm{O}_{4}$
(a) Construct a pair of conversion factors that relate moles of Fe to moles of $\mathrm{Fe}_{3} \mathrm{O}_{4}$
(b) Construct a pair of conversion factors that relate moles of Fe to moles of $\mathrm{O}$ in $\mathrm{Fe}_{3} \mathrm{O}_{4}$
(c) How many moles of Fe are in $2.75 \mathrm{~mol}$ of $\mathrm{Fe}_{3} \mathrm{O}_{4}$ ?
(d) If this compound could be prepared from $\mathrm{Fe}_{2} \mathrm{O}_{3}$ and $\mathrm{O}_{2}$, how many moles of $\mathrm{Fe}_{2} \mathrm{O}_{3}$ would be needed to prepare $4.50 \mathrm{~mol} \mathrm{Fe}_{3} \mathrm{O}_{4} ?$

Dr. Satish Ingale

Numerade Educator

View

Problem 55

How many moles of $\mathrm{H}_{2}$ and $\mathrm{N}_{2}$ can be formed by the decomposition of $0.145 \mathrm{~mol}$ of ammonia, $\mathrm{NH}_{3}$ ?

Jean Gephart

Numerade Educator

02:42

Problem 56

How many moles of $S$ are needed to combine with 0.225 mol Al to give $\mathrm{Al}_{2} \mathrm{~S}_{3}$ ?

Dr. Satish Ingale

Numerade Educator

01:09

Problem 57

How many moles of $\mathrm{UF}_{6}$ would have to be decomposed to provide enough fluorine to prepare $1.25 \mathrm{~mol}$ of $\mathrm{CF}_{4} ?$ (Assume sufficient carbon is available.)

Susan Hallstrom

Numerade Educator

02:13

Problem 58

How many moles of $\mathrm{Fe}_{3} \mathrm{O}_{4}$ are required to supply enough iron to prepare $0.260 \mathrm{~mol} \mathrm{Fe}_{2} \mathrm{O}_{3}$ ? (Assume sufficient oxygen is available.)

Dr. Satish Ingale

Numerade Educator

03:06

Problem 59

How many atoms of carbon are combined with 4.13 moles of hydrogen atoms in a sample of the compound propane, $\mathrm{C}_{3} \mathrm{H}_{8} ?$ (Propane is used as the fuel in gas barbecues.)

Dr. Satish Ingale

Numerade Educator

02:15

Problem 60

How many atoms of hydrogen are found in $2.31 \mathrm{~mol}$ of propane, $\mathrm{C}_{3} \mathrm{H}_{8} ?$

Dr. Satish Ingale

Numerade Educator

03:59

Problem 61

What is the total number of $\mathrm{C}, \mathrm{H},$ and $\mathrm{O}$ atoms in 0.260 moles of glucose, $\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6} ?$

Dr. Satish Ingale

Numerade Educator

02:43

Problem 62

What is the total number of $\mathrm{N}, \mathrm{H},$ and $\mathrm{O}$ atoms $\mathrm{in}$ $0.356 \mathrm{~mol}$ of ammonium nitrate, $\mathrm{NH}_{4} \mathrm{NO}_{3}$, an important fertilizer?

Nishant Kumar

Numerade Educator

03:17

Problem 63

Calcium carbide, $\mathrm{CaC}_{2},$ was once used to make signal flares for ships. Water dripped onto $\mathrm{CaC}_{2}$ reacts to give acetylene $\left(\mathrm{C}_{2} \mathrm{H}_{2}\right)$, which burns brightly. One sample of $\mathrm{CaC}_{2}$ contains $0.150 \mathrm{~mol}$ of carbon. How many moles and how many grams of calcium are also in the sample?

Dr. Satish Ingale

Numerade Educator

05:22

Problem 64

Iodized salt contains a trace amount of calcium iodate, $\mathrm{Ca}\left(\mathrm{IO}_{3}\right)_{2},$ to help prevent a thyroid condition called goiter. How many moles of iodine atoms are in $0.500 \mathrm{~mol}$ of $\mathrm{Ca}\left(\mathrm{IO}_{3}\right)_{2}$ ? How many grams of calcium iodate are needed to supply this much iodine?

Dr. Satish Ingale

Numerade Educator

04:44

Problem 65

How many moles of nitrogen, $\mathrm{N},$ are in $0.650 \mathrm{~mol}$ of ammonium carbonate? How many grams of this compound supply this much nitrogen?

Dr. Satish Ingale

Numerade Educator

03:31

Problem 66

How many moles of nitrogen, $\mathrm{N},$ are in $0.556 \mathrm{~mol}$ of ammonium nitrate? How many grams of this compound supply this much nitrogen?

Dr. Satish Ingale

Numerade Educator

03:59

Problem 67

How many kilograms of a fertilizer made of pure $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{CO}_{3}$ would be required to supply 1 kilogram of nitrogen to the soil?

Dr. Satish Ingale

Numerade Educator

02:50

Problem 68

How many kilograms of a fertilizer made of pure $\mathrm{P}_{2} \mathrm{O}_{5}$ would be required to supply 1 kilogram of phosphorus to the soil?

Dr. Satish Ingale

Numerade Educator

09:50

Problem 69

Calculate the percentage composition by mass for each element in the following:
(a) $\mathrm{NH}_{4} \mathrm{H}_{2} \mathrm{PO}_{4}$
(c) sodium dihydrogen phosphate
(b) $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CO}$
(d) calcium sulfate dihydrate

Dr. Satish Ingale

Numerade Educator

04:41

Problem 70

Calculate the percentage composition by mass for each element in the following:
(a) $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{~N}_{2} \mathrm{H}_{2}$
(c) iron(III) nitrate
(b) $\mathrm{C}_{3} \mathrm{H}_{8}$
(d) aluminum sulfate
Which has a higher percentage of oxygen: morphine $\left(\mathrm{C}_{17} \mathrm{H}_{19} \mathrm{NO}_{3}\right)$ or heroin $\left(\mathrm{C}_{21} \mathrm{H}_{23} \mathrm{NO}_{5}\right) ?$
Which has a higher percentage of nitrogen: carbamazepine, an anticonvulsant, $\left(\mathrm{C}_{15} \mathrm{H}_{12} \mathrm{~N}_{2} \mathrm{O}\right)$ or carbetapentane, a cough suppressant, $\left(\mathrm{C}_{20} \mathrm{H}_{31} \mathrm{NO}_{3}\right)$ ?

Dr. Satish Ingale

Numerade Educator

03:44

Problem 71

Which has a higher percentage of oxygen: morphine $\left(\mathrm{C}_{17} \mathrm{H}_{19} \mathrm{NO}_{3}\right)$ or heroin $\left(\mathrm{C}_{21} \mathrm{H}_{23} \mathrm{NO}_{5}\right) ?$

Dr. Satish Ingale

Numerade Educator

03:35

Problem 72

Which has a higher percentage of nitrogen: carbamazepine, an anticonvulsant, $\left(\mathrm{C}_{15} \mathrm{H}_{12} \mathrm{~N}_{2} \mathrm{O}\right)$ or carbetapentane, a cough suppressant, $\left(\mathrm{C}_{20} \mathrm{H}_{31} \mathrm{NO}_{3}\right)$ ?

Dr. Satish Ingale

Numerade Educator

03:39

Problem 73

Ereon is a trade name for a group of gaseous compounds once used as propellants in aerosol cans. Which has a higher percentage of chlorine: Freon-12 $\left(\mathrm{CCl}_{2} \mathrm{~F}_{2}\right)$ or Freon-141b $\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{Cl}_{2} \mathrm{~F}\right) ?$

Dr. Satish Ingale

Numerade Educator

02:48

Problem 74

Which has a higher percentage of fluorine: Freon-12 $\left(\mathrm{CCl}_{2} \mathrm{~F}_{2}\right)$ or Freon $113\left(\mathrm{C}_{2} \mathrm{Cl}_{3} \mathrm{~F}_{3}\right) ?$

Dr. Satish Ingale

Numerade Educator

04:00

Problem 74

Which has a higher percentage of fluorine: Freon-12 $\left(\mathrm{CCl}_{2} \mathrm{~F}_{2}\right)$ or Freon $113\left(\mathrm{C}_{2} \mathrm{Cl}_{3} \mathrm{~F}_{3}\right) ?$

Dr. Satish Ingale

Numerade Educator

02:18

Problem 75

It was found that $2.35 \mathrm{~g}$ of a compound of phosphorus and chlorine contained $0.539 \mathrm{~g}$ of phosphorus. What are the percentages by mass of phosphorus and chlorine in this compound?

Dr. Satish Ingale

Numerade Educator

02:24

Problem 75

Dr. Satish Ingale

Numerade Educator

02:40

Problem 76

An analysis revealed that $5.67 \mathrm{~g}$ of a compound of nitrogen and oxygen contained $1.47 \mathrm{~g}$ of nitrogen. What are the percentages by mass of nitrogen and oxygen in this compound?

Dr. Satish Ingale

Numerade Educator

07:31

Problem 77

Phencyclidine ("angel dust") is $\mathrm{C}_{17} \mathrm{H}_{25} \mathrm{~N}$. A sample suspected of being this illicit drug was found to have a percentage composition of $84.71 \% \mathrm{C}, 10.42 \% \mathrm{H},$ and $5.61 \% \mathrm{~N}$. Do these data acceptably match the theoretical data for phencyclidine?

Dr. Satish Ingale

Numerade Educator

10:03

Problem 78

The hallucinogenic drug LSD has the molecular formula $\mathrm{C}_{20} \mathrm{H}_{25} \mathrm{~N}_{3} \mathrm{O} .$ One suspected sample contained $74.07 \% \mathrm{C},$
$7.95 \% \mathrm{H},$ and $9.99 \% \mathrm{~N}$
(a) What is the percentage of $\mathrm{O}$ in the sample?
(b) Are these data consistent for $L S D ?$

Dr. Satish Ingale

Numerade Educator

03:43

Problem 79

How many grams of $\mathrm{O}$ are combined with $7.14 \times 10^{21}$ atoms of $\mathrm{N}$ in the compound dinitrogen pentoxide?

Dr. Satish Ingale

Numerade Educator

02:45

Problem 80

How many grams of $\mathrm{C}$ are combined with $4.25 \times 10^{23}$ atoms of $\mathrm{H}$ in the compound $\mathrm{C}_{5} \mathrm{H}_{12} ?$

Dr. Satish Ingale

Numerade Educator

01:06

Problem 81

Write empirical formulas for the following compounds.
(a) $\mathrm{S}_{2} \mathrm{Cl}_{2}$
(d) $\mathrm{As}_{2} \mathrm{O}_{6}$
(b) $\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}$
(e) $\mathrm{H}_{2} \mathrm{O}_{2}$
(c) $\mathrm{NH}_{3}$

Dr. Satish Ingale

Numerade Educator

02:27

Problem 82

What are the empirical formulas of the following compounds?
(a) $\mathrm{C}_{2} \mathrm{H}_{4}(\mathrm{OH})_{2}$
(d) $\mathrm{B}_{2} \mathrm{H}_{6}$
(b) $\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8}$
(e) $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}$
(c) $\mathrm{C}_{4} \mathrm{H}_{10}$

Dr. Satish Ingale

Numerade Educator

07:31

Problem 83

Radioactive sodium pertechnetate is used as a brainscanning agent in medicine. Quantitative analysis of a sample of sodium pertechnetate with a mass of $0.896 \mathrm{~g}$ found $0.111 \mathrm{~g}$ of sodium and $0.477 \mathrm{~g}$ of technetium. The remainder was oxygen. Calculate the empirical formula of sodium pertechnetate.

Dr. Satish Ingale

Numerade Educator

04:44

Problem 84

A sample of Freon was found to contain $0.423 \mathrm{~g}$ of $\mathrm{C}$, $2.50 \mathrm{~g}$ of $\mathrm{Cl}$, and $1.34 \mathrm{~g}$ of $\mathrm{F}$. What is the empirical formula of this compound?

Dr. Satish Ingale

Numerade Educator

05:12

Problem 85

Cinnamic acid, a compound related to the flavor component of cinnamon, is $72.96 \%$ carbon, $5.40 \%$ hydrogen, and the rest is oxygen. What is the empirical formula of this acid?

Dr. Satish Ingale

Numerade Educator

05:05

Problem 86

Vanillin, a compound used as a flavoring agent in food products, has the following percentage composition: $63.2 \% \mathrm{C}, 5.29 \% \mathrm{H},$ and $31.6 \% \mathrm{O} .$ What is the empirical formula of vanillin?

Dr. Satish Ingale

Numerade Educator

04:13

Problem 87

A dry-cleaning fluid composed of only carbon and chlorine was found to be composed of $14.5 \% \mathrm{C}$ and $85.5 \% \mathrm{Cl}$ (by mass). What is the empirical formula of this compound?

Dr. Satish Ingale

Numerade Educator

09:49

Problem 88

One compound of mercury with a molar mass of 519 contains $77.26 \% \mathrm{Hg}, 9.25 \% \mathrm{C},$ and $1.17 \% \mathrm{H}$ (with the balance being $\mathrm{O}$ ). Calculate the empirical formula.

Dr. Satish Ingale

Numerade Educator

05:04

Problem 89

When $0.684 \mathrm{~g}$ of an organic compound containing only carbon, hydrogen, and oxygen was burned in oxygen, $1.312 \mathrm{~g}$ of $\mathrm{CO}_{2}$ and $0.805 \mathrm{~g}$ of $\mathrm{H}_{2} \mathrm{O}$ were obtained. What is the empirical formula of the compound?

Susan Hallstrom

Numerade Educator

View

Problem 90

Methyl ethyl ketone (often abbreviated MEK) is a powerful solvent with many commercial uses. A sample of this compound (which contains only $\mathrm{C}, \mathrm{H},$ and $\mathrm{O}$ ) weighing $0.822 \mathrm{~g}$ was burned in oxygen to give $2.01 \mathrm{~g}$ of $\mathrm{CO}_{2}$ and $0.827 \mathrm{~g}$ of $\mathrm{H}_{2} \mathrm{O}$. What is the empirical formula for MEK?

Susan Hallstrom

Numerade Educator

03:00

Problem 91

When $6.853 \mathrm{mg}$ of a sex hormone was burned in a combustion analysis, $19.73 \mathrm{mg}$ of $\mathrm{CO}_{2}$ and $6.391 \mathrm{mg}$ of $\mathrm{H}_{2} \mathrm{O}$ were obtained. What is the empirical formula of the compound?

Dr. Satish Ingale

Numerade Educator

07:18

Problem 92

When a sample of a compound in the vitamin D family was burned in a combustion analysis, $5.983 \mathrm{mg}$ of the compound gave $18.490 \mathrm{mg}$ of $\mathrm{CO}_{2}$ and $6.232 \mathrm{mg}$ of $\mathrm{H}_{2} \mathrm{O}$. What is the empirical formula of the compound?

Dr. Satish Ingale

Numerade Educator

03:41

Problem 93

The following are empirical formulas and the masses per mole for three compounds. What are their molecular formulas?
(a) $\mathrm{NaS}_{2} \mathrm{O}_{3} ; 270.4 \mathrm{~g} / \mathrm{mol}$
(c) $\mathrm{C}_{2} \mathrm{HCl} ; 181.4 \mathrm{~g} / \mathrm{mol}$
(b) $\mathrm{C}_{3} \mathrm{H}_{2} \mathrm{Cl} ; 147.0 \mathrm{~g} / \mathrm{mol}$

Dr. Satish Ingale

Numerade Educator

03:23

Problem 94

The following are empirical formulas and the masses per mole for three compounds. What are their molecular formulas?
(a) $\mathrm{Na}_{2} \mathrm{SiO}_{3} ; 732.6 \mathrm{~g} / \mathrm{mol}$
(c) $\mathrm{CH}_{3} \mathrm{O} ; 62.1 \mathrm{~g} / \mathrm{mol}$
(b) $\mathrm{NaPO}_{3} ; 305.9 \mathrm{~g} / \mathrm{mol}$

Dr. Satish Ingale

Numerade Educator

02:29

Problem 95

The compound described in Problem 3.91 was found to have a molecular mass of 290 . What is its molecular formula?

Dr. Satish Ingale

Numerade Educator

02:12

Problem 96

The compound described in Problem 3.92 was found to have a molecular mass of 399 . What is the molecular formula of this compound?

Dr. Satish Ingale

Numerade Educator

06:45

Problem 97

A sample of a compound of mercury and bromine with a mass of $0.389 \mathrm{~g}$ was found to contain $0.111 \mathrm{~g}$ bromine. Its molecular mass was found to be 561 . What are its empirical and molecular formulas?

Dr. Satish Ingale

Numerade Educator

View

Problem 98

A $0.6662 \mathrm{~g}$ sample of "antimonal saffron," which is a red pigment used in painting, was found to contain $0.4017 \mathrm{~g}$ of antimony. The remainder was sulfur. The formula mass of this compound is 404 . What are the empirical and molecular formulas of this pigment?

Susan Hallstrom

Numerade Educator

03:07

Problem 99

A sample of a compound of $\mathrm{C}, \mathrm{H}, \mathrm{N},$ and $\mathrm{O},$ was found to have a percentage composition of $27.91 \% \mathrm{C}, 2.341 \% \mathrm{H},$ and $32.56 \% \mathrm{~N}$. Its formula mass is $129 .$ Calculate its empirical and molecular formulas.

Ma Ednelyn Lim

Numerade Educator

09:25

Problem 100

Strychnine, a deadly poison, has a formula mass of 334 and a percentage composition of $75.42 \%$ C, $6.63 \% \mathrm{H}$, $8.38 \% \mathrm{~N},$ and the balance oxygen. Calculate the empirical and molecular formulas of strychnine.

Dr. Satish Ingale

Numerade Educator

03:52

Problem 101

Balance the following equations.
(a) $\mathrm{Mg}(\mathrm{OH})_{2}+\mathrm{HBr} \longrightarrow \mathrm{MgBr}_{2}+\mathrm{H}_{2} \mathrm{O}$
(b) $\mathrm{HCl}+\mathrm{Ca}(\mathrm{OH})_{2} \longrightarrow \mathrm{CaCl}_{2}+\mathrm{H}_{2} \mathrm{O}$
(c) $\mathrm{Al}_{2} \mathrm{O}_{3}+\mathrm{H}_{2} \mathrm{SO}_{4} \longrightarrow \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}+\mathrm{H}_{2} \mathrm{O}$
(d) $\mathrm{KHCO}_{3}+\mathrm{H}_{3} \mathrm{PO}_{4}$
$\mathrm{K}_{2} \mathrm{HPO}_{4}+\mathrm{H}_{2} \mathrm{O}+\mathrm{CO}_{2}$
(e) $\mathrm{C}_{9} \mathrm{H}_{20}+\mathrm{O}_{2} \longrightarrow \mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O}$

Dr. Satish Ingale

Numerade Educator

02:12

Problem 102

Balance the following equations. (a) $\mathrm{CaO}+\mathrm{HNO}_{3} \longrightarrow \mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2}+\mathrm{H}_{2} \mathrm{O}$
(b) $\mathrm{Na}_{2} \mathrm{CO}_{3}+\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2} \longrightarrow \mathrm{MgCO}_{3}+\mathrm{NaNO}_{3}$
(c) $\left(\mathrm{NH}_{4}\right)_{3} \mathrm{PO}_{4}+\mathrm{NaOH} \longrightarrow$
$\mathrm{Na}_{3} \mathrm{PO}_{4}+\mathrm{NH}_{3}+\mathrm{H}_{2} \mathrm{O}$
(d) $\mathrm{LiHCO}_{3}+\mathrm{H}_{2} \mathrm{SO}_{4} \longrightarrow \mathrm{Li}_{2} \mathrm{SO}_{4}+\mathrm{H}_{2} \mathrm{O}+\mathrm{CO}_{2}$
(e) $\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O}+\mathrm{O}_{2} \longrightarrow \mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O}$

Dr. Satish Ingale

Numerade Educator

01:01

Problem 105

Using the diagram below, write the balanced chemical equation.

Dr. Satish Ingale

Numerade Educator

01:23

Problem 106

Using the diagram below, write the balanced chemical equation.

Dr. Satish Ingale

Numerade Educator

08:03

Problem 107

The balanced chemical equation for the combustion of propane, a common heating fuel, is
$$
\mathrm{C}_{3} \mathrm{H}_{8}+5 \mathrm{O}_{2} \longrightarrow 3 \mathrm{CO}_{2}+4 \mathrm{H}_{2} \mathrm{O}
$$
Draw a molecular-level diagram of this chemical reaction. Use the color chart in Section 2.3 to distinguish the atoms from each other.

Dr. Satish Ingale

Numerade Educator

06:53

Problem 108

Draw a molecular-level diagram for the reaction in which sulfur dioxide reacts with molecular oxygen to form sulfur trioxide. Be sure to write and balance the equation first. Use the color chart in Section 2.3 to distinguish the atoms from each other.

Dr. Satish Ingale

Numerade Educator

01:19

Problem 109

Write the equation that expresses in acceptable chemical shorthand the following statement: "Iron can be made to react with molecular oxygen to give iron(III) oxide."

Dr. Satish Ingale

Numerade Educator

01:47

Problem 110

The conversion of one air pollutant, nitrogen monoxide, produced in vehicle engines, into another pollutant, nitrogen dioxide, occurs when nitrogen monoxide reacts with molecular oxygen in the air. Write the balanced equation for this reaction.

Dr. Satish Ingale

Numerade Educator

02:24

Problem 111

A balanced chemical equation contains the term $“ 2 \mathrm{Ba}(\mathrm{OH})_{2} \cdot 8 \mathrm{H}_{2} \mathrm{O} .$ " How many atoms of each element does this represent in the molecular view? How many moles of each element does this represent on the laboratory scale?

Dr. Satish Ingale

Numerade Educator

02:11

Problem 112

A balanced chemical equation contains the term $" 3 \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}$." How many atoms of each element does this represent in the molecular view? How many moles of each element does this represent on the laboratory scale?

Dr. Satish Ingale

Numerade Educator

04:01

Problem 113

Chlorine is used by textile manufacturers to bleach cloth. Excess chlorine is destroyed by its reaction with sodium thiosulfate, $\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}$, as follows.
$$
\begin{aligned}
\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}(a q)+4 \mathrm{Cl}_{2}(g)+5 \mathrm{H}_{2} \mathrm{O} \longrightarrow \\
2 \mathrm{NaHSO}_{4}(a q)+8 \mathrm{HCl}(a q)
\end{aligned}
$$
(a) How many moles of $\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}$ are needed to react with $0.12 \mathrm{~mol}$ of $\mathrm{Cl}_{2}$ ?
(b) How many moles of $\mathrm{HCl}$ can form from $0.12 \mathrm{~mol}$ of $\mathrm{Cl}_{2} ?$
(c) How many moles of $\mathrm{H}_{2} \mathrm{O}$ are required for the reaction
$$
\text { of } 0.12 \mathrm{~mol} \text { of } \mathrm{Cl}_{2} ?
$$
(d) How many moles of $\mathrm{H}_{2} \mathrm{O}$ react if $0.24 \mathrm{~mol} \mathrm{HCl}$ is formed?

Dr. Satish Ingale

Numerade Educator

06:50

Problem 114

The octane in gasoline burns according to the following equation.
$$
2 \mathrm{C}_{8} \mathrm{H}_{18}+25 \mathrm{O}_{2} \longrightarrow 16 \mathrm{CO}_{2}+18 \mathrm{H}_{2} \mathrm{O}
$$
(a) How many moles of $\mathrm{O}_{2}$ are needed to react fully with $6.84 \mathrm{~mol}$ of octane?
(b) How many moles of $\mathrm{CO}_{2}$ can be formed from 0.511 mol of octane?
(c) How many moles of water are produced by the combustion of $8.20 \mathrm{~mol}$ of octane?
(d) If this reaction is used to synthesize $6.00 \mathrm{~mol}$ of $\mathrm{CO}_{2}$, how many moles of oxygen are needed? How many moles of octane?

Dr. Satish Ingale

Numerade Educator

03:29

Problem 115

Propane burns according to the following equation:
$$
\mathrm{C}_{3} \mathrm{H}_{8}+5 \mathrm{O}_{2} \longrightarrow 3 \mathrm{CO}_{2}+4 \mathrm{H}_{2} \mathrm{O}
$$
(a) How many grams of $\mathrm{O}_{2}$ are needed to react fully with $3.45 \mathrm{~mol}$ of propane?
(b) How many grams of $\mathrm{CO}_{2}$ can form from $0.177 \mathrm{~mol}$ of propane?
(c) How many grams of water are produced by the combustion of $4.86 \mathrm{~mol}$ of propane?

Dr. Satish Ingale

Numerade Educator

04:40

Problem 116

The following reaction is used to extract gold from pre-treated gold ore:
$2 \mathrm{Au}(\mathrm{CN})_{2}^{-}(a q)+\mathrm{Zn}(s) \longrightarrow 2 \mathrm{Au}(s)+\mathrm{Zn}(\mathrm{CN})_{4}^{-}(a q)$
(a) How many grams of $Z n$ are needed to react with 0.11 mol of $\mathrm{Au}(\mathrm{CN})_{2}^{-} ?$
(b) How many grams of Au can form from $0.11 \mathrm{~mol}$ of $\mathrm{Au}(\mathrm{CN})_{2}^{-} ?$
(c) How many grams of $\mathrm{Au}(\mathrm{CN})_{2}^{-}$ are required for the reaction of $0.11 \mathrm{~mol}$ of $\mathrm{Zn}$ ?

Dr. Satish Ingale

Numerade Educator

04:49

Problem 117

The incandescent white of a fireworks display is caused by the reaction of phosphorus with $\mathrm{O}_{2}$ to give $\mathrm{P}_{4} \mathrm{O}_{10}$.
(a) Write the balanced chemical equation for the reaction.
(b) How many grams of $\mathrm{O}_{2}$ are needed to combine with $6.85 \mathrm{~g}$ of $\mathrm{P} ?$
(c) How many grams of $\mathrm{P}_{4} \mathrm{O}_{10}$ can be made from $8.00 \mathrm{~g}$ of $\mathrm{O}_{2} ?$
(d) How many grams of $\mathrm{P}$ are needed to make $7.46 \mathrm{~g}$ of $\mathrm{P}_{4} \mathrm{O}_{10} ?$

Dr. Satish Ingale

Numerade Educator

05:09

Problem 118

The combustion of butane, $\mathrm{C}_{4} \mathrm{H}_{10},$ produces carbon dioxide and water. When one sample of $\mathrm{C}_{4} \mathrm{H}_{10}$ was burned, $4.46 \mathrm{~g}$ of water was formed.
(a) Write the balanced chemical equation for the reaction.
(b) How many grams of butane were burned?
(c) How many grams of $\mathrm{O}_{2}$ were consumed?
(d) How many grams of $\mathrm{CO}_{2}$ were formed?

Dr. Satish Ingale

Numerade Educator

02:39

Problem 119

In dilute nitric acid, $\mathrm{HNO}_{3}$, copper metal dissolves according to the following equation.
$3 \mathrm{Cu}(s)+8 \mathrm{HNO}_{3}(a q) \longrightarrow$
$$
3 \mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}(a q)+2 \mathrm{NO}(g)+4 \mathrm{H}_{2} \mathrm{O}
$$
How many grams of $\mathrm{HNO}_{3}$ are needed to dissolve $11.45 \mathrm{~g}$ of Cu according to this equation?

Dr. Satish Ingale

Numerade Educator

03:36

Problem 120

The reaction of hydrazine, $\mathrm{N}_{2} \mathrm{H}_{4},$ with hydrogen peroxide, $\mathrm{H}_{2} \mathrm{O}_{2},$ has been used in rocket engines. One way these compounds react is described by the equation
$$
\mathrm{N}_{2} \mathrm{H}_{4}+7 \mathrm{H}_{2} \mathrm{O}_{2} \longrightarrow 2 \mathrm{HNO}_{3}+8 \mathrm{H}_{2} \mathrm{O}
$$
According to this equation, how many grams of $\mathrm{H}_{2} \mathrm{O}_{2}$ are needed to react completely with $852 \mathrm{~g}$ of $\mathrm{N}_{2} \mathrm{H}_{4} ?$

Dr. Satish Ingale

Numerade Educator

03:01

Problem 121

Oxygen gas can be produced in the laboratory by decomposition of hydrogen peroxide $\left(\mathrm{H}_{2} \mathrm{O}_{2}\right)$
$$
2 \mathrm{H}_{2} \mathrm{O}_{2}(l) \longrightarrow 2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}(g)
$$
How many $\mathrm{kg}$ of $\mathrm{O}_{2}$ can be produced from $1.0 \mathrm{~kg}$ of $\mathrm{H}_{2} \mathrm{O}_{2}$ ?

Dr. Satish Ingale

Numerade Educator

03:45

Problem 122

Oxygen gas can be produced in the laboratory by decomposition of potassium chlorate $\left(\mathrm{KClO}_{3}\right)$
$$
\mathrm{KClO}_{3}(s) \longrightarrow 2 \mathrm{KCl}(s)+3 \mathrm{O}_{2}(g)
$$
How many $\mathrm{kg}$ of $\mathrm{O}_{2}$ can be produced from $1.0 \mathrm{~kg}$ of $\mathrm{KClO}_{3} ?$

Dr. Satish Ingale

Numerade Educator

03:50

Problem 123

Using the balanced equation
$$
2 \mathrm{C}_{2} \mathrm{H}_{6} \mathrm{~S}(g)+9 \mathrm{O}_{2}(g) \longrightarrow 4 \mathrm{CO}_{2}(g)+2 \mathrm{SO}_{2}(g)+6 \mathrm{H}_{2} \mathrm{O}(g)
$$
determine the number of $\mathrm{SO}_{2}$ units formed in the following molecular representation.

Dr. Satish Ingale

Numerade Educator

03:17

Problem 124

Using the balanced chemical equation in Problem 3.123 and the diagram below, determine what the limiting reactant was.

Dr. Satish Ingale

Numerade Educator

07:02

Problem 125

The thermite reaction between powdered aluminum and iron(III) oxide,
$$
2 \mathrm{Al}+\mathrm{Fe}_{2} \mathrm{O}_{3} \longrightarrow \mathrm{Al}_{2} \mathrm{O}_{3}+2 \mathrm{Fe}
$$
produces so much heat the iron that forms is molten, as described in Example 3.16 . Suppose that in one batch of reactants $4.20 \mathrm{~mol}$ of $\mathrm{Al}$ was mixed with $1.75 \mathrm{~mol}$ of $\mathrm{Fe}_{2} \mathrm{O}_{3}$.
(a) Which reactant, if either, was the limiting reactant?
(b) Calculate the number of grams of iron that can be formed from this mixture of reactants.

Dr. Satish Ingale

Numerade Educator

08:48

Problem 126

Ethanol $\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)$ is synthesized for industrial use by the following reaction, carried out at very high pressure:
$$
\mathrm{C}_{2} \mathrm{H}_{4}(g)+\mathrm{H}_{2} \mathrm{O}(g) \longrightarrow \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}(l)
$$
What is the maximum amount, in $\mathrm{kg}$, of ethanol that can be produced when $1.62 \mathrm{~kg}$ of ethylene $\left(\mathrm{C}_{2} \mathrm{H}_{4}\right)$ and $0.0148 \mathrm{~kg}$ of steam are placed into the reaction vessel?

Dr. Satish Ingale

Numerade Educator

05:15

Problem 127

Silver nitrate, $\mathrm{AgNO}_{3}$, reacts with iron(III) chloride, $\mathrm{FeCl}_{3}$, to give silver chloride, $\mathrm{AgCl}$, and iron(III) nitrate, $\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}$ A solution containing $18.0 \mathrm{~g}$ of $\mathrm{AgNO}_{3}$ was mixed with a solution containing $32.4 \mathrm{~g}$ of $\mathrm{FeCl}_{3} .$ How many grams of which reactant remains after the reaction is over?

Dr. Satish Ingale

Numerade Educator

04:18

Problem 128

Chlorine dioxide, $\mathrm{ClO}_{2},$ has been used as a disinfectant in air-conditioning systems. It reacts with water according to the equation
$$
\mathrm{GClO}_{2}+3 \mathrm{H}_{2} \mathrm{O} \longrightarrow 5 \mathrm{HClO}_{3}+\mathrm{HCl}
$$
If $142.0 \mathrm{~g}$ of $\mathrm{ClO}_{2}$ is mixed with $38.0 \mathrm{~g}$ of $\mathrm{H}_{2} \mathrm{O},$ how many grams of which reactant remain if the reaction is complete?

Dr. Satish Ingale

Numerade Educator

View

Problem 129

Some of the acid in acid rain is produced by the following reaction:
$$
3 \mathrm{NO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2 \mathrm{HNO}_{3}(a q)+\mathrm{NO}(g)
$$
If a falling raindrop weighing $0.050 \mathrm{~g}$ comes into contact with $1.0 \mathrm{mg}$ of $\mathrm{NO}_{2}(g)$, how many milligrams of $\mathrm{HNO}_{3}$ can be produced?

Jean Gephart

Numerade Educator

07:11

Problem 130

Phosphorus pentachloride reacts with water to give phosphoric acid and hydrogen chloride according to the following equation.
$$
\mathrm{PCl}_{5}+4 \mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{H}_{3} \mathrm{PO}_{4}+5 \mathrm{HCl}
$$
In one experiment, $0.360 \mathrm{~mol}$ of $\mathrm{PCl}_{5}$ was slowly added to $2.88 \mathrm{~mol}$ of water.
(a) Which reactant, if either, was the limiting reactant?
(b) How many grams of $\mathrm{HCl}$ were formed in the reaction?

Dr. Satish Ingale

Numerade Educator

05:01

Problem 131

Barium sulfate, $\mathrm{BaSO}_{4}$, is made by the following reaction.
$\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}(a q)+\mathrm{Na}_{2} \mathrm{SO}_{4}(a q) \longrightarrow \mathrm{BaSO}_{4}(s)+2 \mathrm{NaNO}_{3}(a q)$
An experiment was begun with $75.00 \mathrm{~g}$ of $\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}$ and an excess of $\mathrm{Na}_{2} \mathrm{SO}_{4}$. After collecting and drying the product, $64.45 \mathrm{~g}$ of $\mathrm{BaSO}_{4}$ was obtained. Calculate the theoretical yield and percentage yield of $\mathrm{BaSO}_{4}$

Dr. Satish Ingale

Numerade Educator

05:23

Problem 132

The Solvay process for the manufacture of sodium carbonate begins by passing ammonia and carbon dioxide through a solution of sodium chloride to make sodium bicarbonate and ammonium chloride. The equation for the overall reaction is
$\mathrm{H}_{2} \mathrm{O}+\mathrm{NaCl}+\mathrm{NH}_{3}+\mathrm{CO}_{2} \longrightarrow \mathrm{NH}_{4} \mathrm{Cl}+\mathrm{NaHCO}_{3}$
In the next step, sodium bicarbonate is heated to give sodium carbonate and two gases, carbon dioxide and steam.
$2 \mathrm{NaHCO}_{3} \longrightarrow \mathrm{Na}_{2} \mathrm{CO}_{3}+\mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O}$
What is the theoretical yield of sodium carbonate, expressed in grams, if $120 \mathrm{~g}$ of $\mathrm{NaCl}$ was used in the first reaction? If $85.4 \mathrm{~g}$ of $\mathrm{Na}_{2} \mathrm{CO}_{3}$ was obtained, what was the percentage yield?

Dr. Satish Ingale

Numerade Educator

03:59

Problem 133

Aluminum sulfate can be made by the following reaction.
$2 \mathrm{AlCl}_{3}(a q)+3 \mathrm{H}_{2} \mathrm{SO}_{4}(a q) \longrightarrow \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}(a q)+6 \mathrm{HCl}(a q)$
It is quite soluble in water, so to isolate it the solution has to be evaporated to dryness. This drives off the volatile $\mathrm{HCl},$ but the residual solid has to be heated to a little over $200^{\circ} \mathrm{C}$ to drive off all of the water. In one experiment, $25.0 \mathrm{~g}$ of $\mathrm{AlCl}_{3}$ was mixed with $30.0 \mathrm{~g}$ of $\mathrm{H}_{2} \mathrm{SO}_{4}$. Eventually, $28.46 \mathrm{~g}$ of pure $\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}$ was isolated. Calculate the percentage yield.

Oluwapelumi Kolawole

Numerade Educator

07:16

Problem 134

The combustion of methyl alcohol in an abundant excess of oxygen follows the equation
$$
2 \mathrm{CH}_{3} \mathrm{OH}+3 \mathrm{O}_{2} \longrightarrow 2 \mathrm{CO}_{2}+4 \mathrm{H}_{2} \mathrm{O}
$$
When $6.40 \mathrm{~g}$ of $\mathrm{CH}_{3} \mathrm{OH}$ was mixed with $10.2 \mathrm{~g}$ of $\mathrm{O}_{2}$ and ignited, $6.12 \mathrm{~g}$ of $\mathrm{CO}_{2}$ was obtained. What was the percentage yield of $\mathrm{CO}_{2} ?$

Dr. Satish Ingale

Numerade Educator

06:06

Problem 135

Manganese(III) fluoride, $\mathrm{MnF}_{3}$, can be prepared by the following reaction.
$$
2 \mathrm{MnI}_{2}(s)+13 \mathrm{~F}_{2}(g) \longrightarrow 2 \mathrm{MnF}_{3}(s)+4 \mathrm{IF}_{5}(l)
$$
If the percentage yield of $\mathrm{MnF}_{3}$ is always approximately $56 \%$, how many grams of $\mathrm{MnF}_{3}$ can be expected if 10.0 grams of each reactant is used in an experiment?

Dr. Satish Ingale

Numerade Educator

04:35

Problem 136

The potassium salt of benzoic acid, potassium benzoate $\left(\mathrm{KC}_{7} \mathrm{H}_{5} \mathrm{O}_{2}\right),$ can be made by the action of potassium permanganate on toluene $\left(\mathrm{C}_{7} \mathrm{H}_{8}\right)$ as follows.
$\mathrm{C}_{7} \mathrm{H}_{8}+2 \mathrm{KMnO}_{4} \longrightarrow$
$$
\mathrm{KC}_{7} \mathrm{H}_{5} \mathrm{O}_{2}+2 \mathrm{MnO}_{2}+\mathrm{KOH}+\mathrm{H}_{2} \mathrm{O}
$$
If the yield of potassium benzoate cannot realistically be expected to be more than $71 \%$, what is the minimum number of grams of toluene needed to produce $11.5 \mathrm{~g}$ of potassium benzoate?

Dr. Satish Ingale

Numerade Educator

07:09

Problem 137

Mercury is an environmental pollutant because it can be converted by certain bacteria into the extremely poisonous substance dimethyl mercury, $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{Hg} .$ This compound ends up in the food chain and accumulates in the tissues of aquatic organisms, particularly fish, which renders them unsafe to eat. It is estimated that in the United States 263 tons of mercury are released into the atmosphere each year. If only $1.0 \%$ of this mercury is eventually changed to $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{Hg}$, how many pounds of this compound are formed annually?

Dr. Satish Ingale

Numerade Educator

06:53

Problem 138

Lead compounds are often highly colored and are toxic to mold, mildew, and bacteria, properties that in the past were useful for paints used before 1960 . Today we know lead is very hazardous and it is not used in paint; however, old paint is still a problem. If a certain lead-based paint contains $14.5 \% \mathrm{PbCr}_{2} \mathrm{O}_{7}$ and $73 \%$ of the paint evaporates as it dries, what mass of lead will be in a paint chip that weighs $0.15 \mathrm{~g}$ ?

Dr. Satish Ingale

Numerade Educator

04:54

Problem 139

A superconductor is a substance that is able to conduct electricity without resistance, a property that is very desirable in the construction of large electromagnets. Metals have this property if cooled to temperatures a few degrees above absolute zero, but this requires the use of expensive liquid helium (boiling point $4 \mathrm{~K}$ ). Scientists have discovered materials that become superconductors at higher temperatures, but they are ceramics. Their brittle nature has so far prevented them from being made into long wires. A recently discovered compound of magnesium and boron, which consists of $52.9 \% \mathrm{Mg}$ and $47.1 \% \mathrm{~B}$, shows special promise as a high-temperature superconductor because it is inexpensive to make and can be fabricated into wire relatively easily. What is the formula of this compound?

Dr. Satish Ingale

Numerade Educator

07:29

Problem 140

A compound of $\mathrm{Ca}, \mathrm{C}, \mathrm{N},$ and $\mathrm{S}$ was subjected to quantitative analysis and formula mass determination, and the following data were obtained. A $0.250 \mathrm{~g}$ sample was mixed with $\mathrm{Na}_{2} \mathrm{CO}_{3}$ to convert all of the Ca to $0.160 \mathrm{~g}$ of $\mathrm{CaCO}_{3}$. A $0.115 \mathrm{~g}$ sample of the compound was carried through a series of reactions until all of its $S$ was changed to $0.344 \mathrm{~g}$ of $\mathrm{BaSO}_{4}$. A $0.712 \mathrm{~g}$ sample was processed to liberate all of its $\mathrm{N}$ as $\mathrm{NH}_{3}$, and $0.155 \mathrm{~g}$ of $\mathrm{NH}_{3}$ was obtained. The formula mass was found to be 156 . Determine the empirical and molecular formulas of this compound.

Henry He

Numerade Educator

04:40

Problem 141

Ammonium nitrate will detonate if ignited in the presence of certain impurities. The equation for this reaction at a high temperature is
$2 \mathrm{NH}_{4} \mathrm{NO}_{3}(s) \stackrel{>300^{\circ} \mathrm{C}}{\longrightarrow} 2 \mathrm{~N}_{2}(g)+\mathrm{O}_{2}(g)+4 \mathrm{H}_{2} \mathrm{O}(g)$
Notice that all of the products are gases, so they occupy a vastly greater volume than the solid reactant. How many moles of all gases are produced from $1 \mathrm{~mol}$ of $\mathrm{NH}_{4} \mathrm{NO}_{3}$ ? If 1.00 ton of $\mathrm{NH}_{4} \mathrm{NO}_{3}$ exploded according to this equation, how many moles of all gases would be produced? $(1$ ton $=2000$ lb. $)$

Dr. Satish Ingale

Numerade Educator

03:35

Problem 142

A lawn fertilizer is rated as $6.00 \%$ nitrogen, meaning $6.00 \mathrm{~g}$ of $\mathrm{N}$ in $100 \mathrm{~g}$ of fertilizer. The nitrogen is present in the form of urea, $\left(\mathrm{NH}_{2}\right)_{2} \mathrm{CO} .$ How many grams of urea are present in $100 \mathrm{~g}$ of the fertilizer to supply the rated amount of nitrogen?

Dr. Satish Ingale

Numerade Educator

01:41

Problem 143

Nitrogen is the "active ingredient" in many quick-acting fertilizers. You are operating a farm of 1500 acres to produce soybeans. Which of the following fertilizers will you choose as the most economical for your farm?
(a) $\mathrm{NH}_{4} \mathrm{NO}_{3}$ at $\$ 625$ for $25 \mathrm{~kg}$
(b) $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{HPO}_{4}$ at $\$ 55$ for $1 \mathrm{~kg}$
(c) urea, $\mathrm{CH}_{4} \mathrm{ON}_{2}$, at $\$ 60$ for $5 \mathrm{~kg}$
(d) ammonia, $\mathrm{NH}_{3}$ at $\$ 128$ for $50 \mathrm{~kg}$

Isabella Huang

Numerade Educator

03:26

Problem 144

Based solely on the amount of available carbon, how many grams of sodium oxalate, $\mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4},$ could be obtained from $125 \mathrm{~g}$ of $\mathrm{C}_{6} \mathrm{H}_{6}$ ? (Assume that no loss of carbon occurs in any of the reactions needed to produce the $\mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4}$.)

Susan Hallstrom

Numerade Educator

06:07

Problem 145

According to NASA, the space shuttle's external fuel tank for the main propulsion system carries $1,361,936 \mathrm{lb}$ of liquid oxygen and $227,641 \mathrm{lb}$ of liquid hydrogen. During takeoff, these chemicals are consumed as they react to form water. If the reaction is continued until all of one reactant is gone, how many pounds of which reactant are left over?

Henry He

Numerade Educator

03:47

Problem 146

For a research project, a student decided to test the effect of the lead(II) ion $\left(\mathrm{Pb}^{2+}\right)$ on the ability of salmon eggs to hatch. This ion was obtainable from the water-soluble salt, lead(II) nitrate, $\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2},$ which the student decided to make by the following reaction. (The desired product was to be isolated by the slow evaporation of the water.)
$\mathrm{PbO}(s)+2 \mathrm{HNO}_{3}(a q) \longrightarrow \mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}(a q)+\mathrm{H}_{2} \mathrm{O}$
Losses of product for various reasons were expected, and a yield of $86.0 \%$ was expected. In order to have $5.00 \mathrm{~g}$ of product at this yield, how many grams of $\mathrm{PbO}$ should be taken? (Assume that sufficient nitric acid, $\mathrm{HNO}_{3}$, would be used.

Dr. Satish Ingale

Numerade Educator

04:24

Problem 147

Chlorine atoms cause chain reactions in the stratosphere that destroy ozone that protects the earth's surface from ultraviolet radiation. The chlorine atoms come from chlorofluorocarbons, compounds that contain carbon, fluorine, and chlorine, which were used for many years as refrigerants. One of these compounds is Freon-12, $\mathrm{CF}_{2} \mathrm{Cl}_{2}$. If a sample contains $1.0 \times 10^{-9} \mathrm{~g}$ of $\mathrm{Cl}$, how many grams of $\mathrm{F}$ should be present if all of the $\mathrm{F}$ and $\mathrm{Cl}$ atoms in the sample came from $\mathrm{CF}_{2} \mathrm{Cl}_{2}$ molecules?

Dr. Satish Ingale

Numerade Educator

03:37

Problem 148

Lime, $\mathrm{CaO},$ can be produced in two steps as shown in the equations below. If the percentage yield of the first step is $83.5 \%$ and the percentage yield of the second step is $71.4 \%$, what is the expected overall percentage yield for producing $\mathrm{CaO}$ from $\mathrm{CaCl}_{2} ?$
$$
\begin{aligned}
\mathrm{CaCl}_{2}(a q)+\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{CaCO}_{3}(s)+2 \mathrm{HCl}(a q) \\
\mathrm{CaCO}_{3}(s) \stackrel{\text { heat }}{\longrightarrow} \mathrm{CaO}(s)+\mathrm{CO}_{2}(g)
\end{aligned}
$$

Dr. Satish Ingale

Numerade Educator

01:12

Problem 149

A newspaper story describing the local celebration of Mole Day on October 23 (selected for Avogadro's number, $\left.6.02 \times 10^{23}\right)$ attempted to give the readers a sense of the size of the number by stating that a mole of $M \& M$ would be equal to 18 tractor trailers full. Assuming that an M\&M occupies a volume of about $0.5 \mathrm{~cm}^{3}$, calculate the dimensions of a cube required to hold one mole of M\&Ms. Would 18 tractor trailers be sufficient?

Crystal Wang

Numerade Educator

02:55

Problem 150

Suppose you had one mole of pennies and you were going to spend 500 million dollars each and every second until you spent your entire fortune. How many years would it take you to spend all this cash? (Assume 1 year = 365 days.)

Isabella Huang

Numerade Educator

01:12

Problem 151

Using the above two questions as examples, devise a creative way to demonstrate the size of the mole, or Avogadro's number.

Crystal Wang

Numerade Educator

03:54

Problem 152

List the different ways in which a chemist could use the information used to determine empirical formulas.

Dr. Satish Ingale

Numerade Educator