Chemistry Structure and Properties

Nivaldo J. Tro

Chapter 11 Gases - all with Video Answers

Educators

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Chapter Questions

00:21

Problem 1

What is pressure? What causes pressure?

Sisi Gao

Numerade Educator

01:51

Problem 2

How does pressure change as a function of altitude?

Kevin Chimex

Numerade Educator

00:59

Problem 3

Explain the risks associated with uncontrolled decompression.

Eugene Schneider

University of Minnesota - Twin Cities

01:22

Problem 4

What are the common units of pressure? List them in order of small-
est to largest unit.

Dalton Hilovsky

Numerade Educator

00:56

Problem 5

What is a manometer? How does it measure the pressure of a sample
of gas?

Sisi Gao

Numerade Educator

03:31

Summarize each of the simple gas laws (Boyle's law, Charles's law, and Avogadro's law). For each law, explain the relationship between the two variables it addresses and also state which variables must be kept constant.

Kevin Chimex

Numerade Educator

01:06

Problem 7

Explain the source of ear pain experienced due to a rapid change in
altitude.

Eugene Schneider

University of Minnesota - Twin Cities

02:40

Problem 8

Why must scuba divers never hold their breath as they ascend to the
surface?

Kevin Chimex

Numerade Educator

00:57

Problem 9

Why is the second story of a house usually warmer than the ground
story?

Eugene Schneider

University of Minnesota - Twin Cities

02:23

Problem 10

Explain why hot-air balloons float above the ground.

Kevin Chimex

Numerade Educator

00:15

Problem 11

What is the ideal gas law? Why is it useful?

Sisi Gao

Numerade Educator

07:56

Problem 12

Explain how the ideal gas law contains within it the simple gas laws
(show an example).

Matthew Bamidele

Numerade Educator

00:41

Problem 13

Define molar volume and give its value for a gas at STP.

Eugene Schneider

University of Minnesota - Twin Cities

05:07

Problem 14

How does the density of a gas depend on temperature? Pressure? How
does it depend on the molar mass of the gas?

Matthew Bamidele

Numerade Educator

00:19

Problem 15

What is partial pressure? What is the relationship between the partial
pressures of each gas in a sample and the total pressure of gas in the
sample?

Sisi Gao

Numerade Educator

04:36

Problem 16

Why do deep-sea divers breathe a mixture of helium and oxygen?

Matthew Bamidele

Numerade Educator

00:20

Problem 17

When a gas is collected over water, is the gas pure? Why or why not?
How can the partial pressure of the collected gas be determined?

Sisi Gao

Numerade Educator

00:59

Problem 18

What are the basic postulates of kinetic molecular theory? How does the
concept of pressure follow from kinetic molecular theory?

Sisi Gao

Numerade Educator

20:45

Problem 19

Explain how Boyle's law, Charles's law, Avogadro's law, and Dalton's law
all follow from kinetic molecular theory.

Matthew Bamidele

Numerade Educator

00:21

Problem 20

How is the kinetic energy of a gas related to temperature? How is the
root mean square velocity of a gas related to its molar mass?

Sisi Gao

Numerade Educator

04:29

Problem 21

Describe how perfume molecules travel from the bottle to your nose.
What is mean free path?

Matthew Bamidele

Numerade Educator

01:16

Problem 22

Explain the difference between diffusion and effusion. How is the effu-
sion rate of a gas related to its molar mass?

Dalton Hilovsky

Numerade Educator

01:36

Problem 23

If a reaction occurs in the gas phase at STP, the mass of a product can be
determined from the volumes of reactants. Explain.

Kevin Chimex

Numerade Educator

02:15

Problem 24

Deviations from the ideal gas law are often observed at high pressure and
low temperature. Explain this in light of kinetic molecular theory.

Eugene Schneider

University of Minnesota - Twin Cities

03:33

Problem 25

The pressure in Denver, Colorado (elevation 5280 $\mathrm{ft}$ or $1600 \mathrm{m} ),$ averages about 24.9 in Hg. Convert this pressure to
\begin{equation}\begin{array}{ll}{\text { a. }} & {\text { atm }} & {\text { b. } \mathrm{mmHg}} \\ {\text { c. }} & {\text { psi }} & {\text { d. } \mathrm{Pa}}\end{array}\end{equation}

Dalton Hilovsky

Numerade Educator

02:53

Problem 26

The pressure on top of Mount Everest (29,029 ft or 8848 m) averages
about 235 mmHg. Convert this pressure to
\begin{equation}\begin{array}{ll}{\text { a. torr }} & {\text { b. psi }} \\ {\text { c. in Hg }} & {\text { d. atm }}\end{array}\end{equation}

Sara Kolms

Numerade Educator

02:39

Problem 27

The North American record for highest recorded barometric pressure is
31.85 in Hg, set in 1989 in Northway, Alaska. Convert this pressure to:
\begin{equation}\begin{array}{ll}{\text { a. } \mathrm{mmHg}} & {\text { b. } \mathrm{atm}} \\ {\text { c. torr }} & {\text { d. } \mathrm{kPa}(\text { kilopascals })}\end{array}\end{equation}

Dalton Hilovsky

Numerade Educator

02:20

Problem 28

The world record for lowest pressure (at sea level) was 652.5 mmHg
recorded inside Typhoon Tip on October 12, 1979, in the western
Pacific Ocean. Convert this pressure to:\begin{equation}\begin{array}{ll}{\text { a. torr }} & {\text { b. atm }} \\ {\text { c. in } \mathrm{Hg}} & {\text { d. psi }}\end{array}\end{equation}

Dalton Hilovsky

Numerade Educator

03:24

Problem 29

If the barometric pressure is 762.4 mmHg, what is the pressure of the
gas sample shown in each illustration?

Kevin Chimex

Numerade Educator

01:35

Problem 30

If the barometric pressure is 751.5 mmHg, what is the pressure of the
gas sample shown in each illustration?

Eugene Schneider

University of Minnesota - Twin Cities

03:20

Problem 31

A sample of gas has an initial volume of 5.6 L at a pressure of 735 mmHg.
If the volume of the gas is increased to 9.4 L, what is its pressure?

Clark Whitney

Numerade Educator

02:01

Problem 32

A sample of gas has an initial volume of 13.9 L at a pressure of 1.22 atm.
If the sample is compressed to a volume of 10.3 L, what is its pressure?

Matthew Bamidele

Numerade Educator

01:41

Problem 33

A 48.3 -mL sample of gas in a cylinder is warmed from $22^{\circ} \mathrm{C}$ to $87^{\circ} \mathrm{C}$ .What is its volume at the final temperature?

Dalton Hilovsky

Numerade Educator

02:02

Problem 34

A syringe containing 1.55 $\mathrm{mL}$ of oxygen gas is cooled from $95.3^{\circ} \mathrm{C}$ to
$0.0^{\circ} \mathrm{C} .$ What is the final volume of oxygen gas?

Matthew Bamidele

Numerade Educator

03:03

Problem 35

A balloon contains 0.158 mol of gas and has a volume of 2.46 L. If we
add 0.113 mol of gas to the balloon (at the same temperature and pressure), what is its final volume?

Kevin Chimex

Numerade Educator

01:15

Problem 36

A cylinder with a moveable piston contains 0.553 mol of gas and has a
volume of 253 $\mathrm{mL} .$ What is its volume if we add 0.365 mol of gas to the
cylinder? (Assume constant temperature and pressure.)

Eugene Schneider

University of Minnesota - Twin Cities

05:03

Problem 37

What volume does 0.118 mol of helium gas at a pressure of 0.97 atm and
a temperature of 305 $\mathrm{K}$ occupy? Would the volume be different if the gas
was argon (under the same conditions)?

Kevin Chimex

Numerade Educator

02:56

Problem 38

What volume does 12.5 g of argon gas at a pressure of 1.05 atm and a
temperature of 322 $\mathrm{K}$ occupy? Would the volume be different if the sample were 12.5 $\mathrm{g}$ of helium (under identical conditions)?

Eugene Schneider

University of Minnesota - Twin Cities

00:52

Problem 39

What is the pressure in a $10.0-$ L cylinder filled with 0.448 mol of nitrogen gas at a temperature of 315 $\mathrm{K}$ ?

Sisi Gao

Numerade Educator

01:31

Problem 40

What is the pressure in a $15.0-$ L cylinder filled with 32.7 g of oxygen gas
at a temperature of 302 $\mathrm{K}$ ?

Eugene Schneider

University of Minnesota - Twin Cities

00:24

Problem 41

A cylinder contains 28.5 L of oxygen gas at a pressure of 1.8 atm and a
temperature of 298 $\mathrm{K}$ . How much gas (in moles) is in the cylinder?

Sisi Gao

Numerade Educator

02:08

Problem 42

What is the temperature of 0.52 mol of gas at a pressure of 1.3 atm and a
volume of 11.8 $\mathrm{L}$ ?

Matthew Bamidele

Numerade Educator

04:11

Problem 43

An automobile tire has a maximum rating of 38.0 psi (gauge pressure). The tire is inflated (while cold) to a volume of 11.8 $\mathrm{L}$ and a gauge pressure of 36.0 psi at a temperature of $12.0^{\circ} \mathrm{C} .$ When the car is drivenon a hot day, the tire warms to $65.0^{\circ} \mathrm{C}$ and its volume expands to 12.2 L. Does the pressure in the tire exceed its maximum rating? (Note: The gauge pressure is the difference between the total pressure and atmospheric pressure. In this case, assume that atmospheric pressure is
14.7 psi.

Dalton Hilovsky

Numerade Educator

02:52

Problem 44

A weather balloon is inflated to a volume of 28.5 $\mathrm{L}$ at a pressure of 748
$\mathrm{mm} \mathrm{Hg}$ and a temperature of $28.0^{\circ} \mathrm{C}$ .The balloon rises in the atmosphere to an altitude of approximately $25,000$ feet, where the pressure is 385 $\mathrm{mm} \mathrm{Hg}$ and the temperature is $-15.0^{\circ} \mathrm{C}$ . Assuming the balloon can
freely expand, calculate the volume of the balloon at this altitude.

Dalton Hilovsky

Numerade Educator

02:37

Problem 45

A piece of dry ice (solid carbon dioxide) with a mass of 28.8 $\mathrm{g}$ sublimes
(converts from solid to gas into a large balloon. Assuming that all of the
carbon dioxide ends up in the balloon, what is the volume of the balloon
at a temperature of $22^{\circ} \mathrm{C}$ and a pressure of 742 $\mathrm{mm}$ ?

Dalton Hilovsky

Numerade Educator

08:24

Problem 46

A 1.0 -L container of liquid nitrogen is kept in a closet measuring 1.0 $\mathrm{m}$ by 1.0 $\mathrm{m}$ by 2.0 $\mathrm{m} .$ Assuming that the container is completely full, that the temperature is $25.0^{\circ} \mathrm{C},$ and that the atmospheric pressure is 1.0 atm, calculate the percent (by volume) of air that is displaced if all of the liquid nitrogen evaporates. (Liquid nitrogen has a density of 0.807 $\mathrm{g} / \mathrm{mL} .$ .

Matthew Bamidele

Numerade Educator

04:34

Problem 47

A wine-dispensing system uses argon canisters to pressurize and preserve wine in the bottle. An argon canister for the system has a volume of 55.0 $\mathrm{mL}$ and contains 26.0 $\mathrm{g}$ of argon. Assuming ideal gas behavior, what is the pressure in the canister at 295 $\mathrm{K}^{2}$ When the argon is released from the canister, it expands to fill the wine bottle. How many $750.0-\mathrm{mL}$ wine bottles can be purged with the argon in the canister at a pressure of 1.20 atm and a temperature of 295 $\mathrm{K} ?$

Michelle Neer

Numerade Educator

02:27

Problem 48

Pressurized carbon dioxide inflators can be used to inflate a bicycle tire in the event of a flat. These inflators use metal cartridges that contain 16.0 $\mathrm{g}$ of carbon dioxide. $\mathrm{At} 298 \mathrm{K},$ to what gauge pressure (in psi) can the carbon dioxide in the cartridge inflate a $3.45-$ L mountain bike tire? (Note: The gauge pressure is the difference between the total pressure and atmospheric pressure. In this case, assume that atmospheric pressure is 14.7 psi.)

Eugene Schneider

University of Minnesota - Twin Cities

01:31

Problem 49

Which gas sample illustrated here has the greatest pressure? Assume
that all the samples are at the same temperature. Explain.

Kevin Chimex

Numerade Educator

01:36

Problem 50

This picture represents a sample of gas at a pressure of 1 atm, a volume
of $1 \mathrm{L},$ and a temperature of $25^{\circ} \mathrm{C}$ . Draw a similar picture showing
what would happen to the sample if the volume were reduced to 0.5 $\mathrm{L}$
and the temperature were increased to $250^{\circ} \mathrm{C} .$ What would happen to
the pressure?

Dalton Hilovsky

Numerade Educator

01:16

Problem 51

Aerosol cans carry clear warnings against incineration because of the
high pressures that can develop if they are heated. Suppose that a can
contains a residual amount of gas at a pressure of 755 mmHg and a temperature of $25^{\circ} \mathrm{C} .$ What would the pressure be if the can were heated
to $1155^{\circ} \mathrm{C}$ ?

Dalton Hilovsky

Numerade Educator

01:58

Problem 52

A sample of nitrogen gas in a $1.75-\mathrm{L}$ container exerts a pressure of
1.35 atm at $25^{\circ} \mathrm{C} .$ What is the pressure if the volume of the container is
maintained constant and the temperature is raised to $355^{\circ} \mathrm{C}$ ?

Dalton Hilovsky

Numerade Educator

00:36

Problem 53

Use the molar volume of a gas at STP to determine the volume (in L)
occupied by 33.6 $\mathrm{g}$ of neon at STP.

Sisi Gao

Numerade Educator

01:59

Problem 54

Use the molar volume of a gas at STP to calculate the density (in $\mathrm{g} / \mathrm{L}$ ) of
nitrogen gas at STP.

Matthew Bamidele

Numerade Educator

01:51

Problem 55

What is the density (in $\mathrm{g} / \mathrm{L} )$ of hydrogen gas at $20.0^{\circ} \mathrm{C}$ and a pressure of 1655 psi?

Ly Tran

Numerade Educator

03:41

Problem 56

A sample of $\mathrm{N}_{2} \mathrm{O}$ gas has a density of 2.85 $\mathrm{g} / \mathrm{L}$ at 298 $\mathrm{K} .$ What is the pressure of the gas (in $\mathrm{mmHg} )$ )?

Matthew Bamidele

Numerade Educator

00:35

Problem 57

A $248-\mathrm{mL}$ gas sample has a mass of 0.433 $\mathrm{g}$ at a pressure of 745 $\mathrm{mmHg}$ and a temperature of $28^{\circ} \mathrm{C} .$ What is the molar mass of the gas?

Sisi Gao

Numerade Educator

04:25

Problem 58

A $113-\mathrm{mL}$ gas sample has a mass of 0.171 $\mathrm{g}$ at a pressure of 721 $\mathrm{mm} \mathrm{Hg}$
and a temperature of $32^{\circ} \mathrm{C} .$ What is the molar mass of the gas?

Matthew Bamidele

Numerade Educator

00:45

Problem 59

A sample of gas has a mass of 38.8 $\mathrm{mg}$ . Its volume is 224 $\mathrm{mL}$ at a temperature of $55^{\circ} \mathrm{C}$ and a pressure of 886 torr. Find the molar mass of
the gas.

Sisi Gao

Numerade Educator

02:54

Problem 60

A sample of gas has a mass of 0.555 $\mathrm{g}$ . Its volume is 117 $\mathrm{mL}$ at a temperature of $85^{\circ} \mathrm{C}$ and a pressure of 753 $\mathrm{mm} \mathrm{Hg}$ . Find the molar mass of the gas.

Dalton Hilovsky

Numerade Educator

02:01

Problem 61

A gas mixture contains each of these gases at the indicated partial pressures: $\mathrm{N}_{2}, 215$ torr; $\mathrm{O}_{2}, 102$ torr; and He, 117 torr. What is the total
pressure of the mixture? What mass of each gas is present in a $1.35-\mathrm{L}$
sample of this mixture at $25.0^{\circ} \mathrm{C} ?$

Sisi Gao

Numerade Educator

04:30

Problem 62

A gas mixture with a total pressure of 745 $\mathrm{mm} \mathrm{Hg}$ contains each of these
gases at the indicated partial pressures: $\mathrm{CO}_{2}, 125 \mathrm{mmHg} ; \mathrm{Ar}, 214 \mathrm{mmHg}$ ; and $\mathrm{O}_{2}, 187 \mathrm{mmHg}$ . The mixture also contains helium gas. What is the partial pressure of the helium gas? What mass of helium gas is present in
a 12.0 -L sample of this mixture at 273 $\mathrm{K}$ ?

Andrew Macphail

Numerade Educator

05:47

Problem 63

We add a $1.20-$ g sample of dry ice to a $755-\mathrm{mL}$ flask containing nitro-
gen gas at a temperature of $25.0^{\circ} \mathrm{C}$ and a pressure of 725 $\mathrm{mmH} \mathrm{g}$ . The dry ice sublimes (converts from solid to gas) and the mixture returns to
$25.0^{\circ} \mathrm{C} .$ What is the total pressure in the flask?

Dalton Hilovsky

Numerade Educator

02:31

Problem 64

A $275-\mathrm{mL}$ flask contains pure helium at a pressure of 752 torr. A sec-
ond flask with a volume of 475 $\mathrm{mL}$ contains pure argon at a pressure of
722 torr. If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of each gas and the total pressure?

Eugene Schneider

University of Minnesota - Twin Cities

01:15

Problem 65

A gas mixture contains 1.25 $\mathrm{gN}_{2}$ and 0.85 $\mathrm{g} \mathrm{O}_{2}$ in a $1.55-\mathrm{L}$ container at $18^{\circ} \mathrm{C} .$ Calculate the mole fraction and partial pressure of each component in the gas mixture.

Sisi Gao

Numerade Educator

02:52

Problem 66

What is the mole fraction of oxygen gas in air (see Table 11.2$)$ ? What
volume of air contains 10.0 g of oxygen gas at 273 $\mathrm{K}$ and 1.00 $\mathrm{atm}$ ?

Eugene Schneider

University of Minnesota - Twin Cities

01:12

Problem 67

The hydrogen gas formed in a chemical reaction is collected over water
at $30.0^{\circ} \mathrm{C}$ at a total pressure of 732 $\mathrm{mm} \mathrm{Hg}$ . What is the partial pressure of the hydrogen gas collected in this way: If the total volume of gas collected is $722 \mathrm{mL},$ what mass of hydrogen gas is collected?

Sisi Gao

Numerade Educator

02:47

Problem 68

The air in a bicycle tire is bubbled through water and collected at $25^{\circ} \mathrm{C}$ .
If the total volume of gas collected is 5.45 L at a temperature of $25^{\circ} \mathrm{C}$
and a pressure of 745 torr, how many moles of gas were in the bicycle tire?

Matthew Bamidele

Numerade Educator

03:20

Problem 69

The zinc within a copper-plated penny will dissolve in hydrochloric
acid if the copper coating is filed down in several spots (so that the hy-
drochloric acid can get to the zinc). The reaction between the acid and the zinc is $2 \mathrm{H}^{+}(a q)+\mathrm{Zn}(s) \longrightarrow \mathrm{H}_{2}(g)+\mathrm{Zn}^{2+}(a q) .$ When the
zinc in a certain penny dissolves, the total volume of gas collected over
water at $25^{\circ} \mathrm{C}$ is 0.951 $\mathrm{L}$ at a total pressure of 748 $\mathrm{mm} \mathrm{Hg.}$ What mass
of hydrogen gas is collected?

Dalton Hilovsky

Numerade Educator

04:28

Problem 70

A heliox deep-sea diving mixture contains 2.0 $\mathrm{g}$ of oxygen to every
98.0 $\mathrm{g}$ of helium. What is the partial pressure of oxygen when this
mixture is delivered at a total pressure of 8.5 $\mathrm{atm}$ ?

Matthew Bamidele

Numerade Educator

02:49

Problem 71

Consider a $1.0-\mathrm{L}$ sample of helium gas and a $1.0-\mathrm{L}$ sample of argon gas, both at room temperature and atmospheric pressure.
a. Do the atoms in the helium sample have the same average kinetic energy as the atoms in the argon sample?
b. Do the atoms in the helium sample have the same average velocity as the atoms in the argon sample?
c. Do the argon atoms, because they are more massive, exert a greater pressure on the walls of the container' Explain.
d. Which gas sample has the faster rate of effusion?

Dalton Hilovsky

Numerade Educator

02:07

Problem 72

\begin{equation}\begin{array}{l}{\text { A flask at room temperature contains exactly equal amounts (in moles) }} \\ {\text { of nitrogen and xenon. }} \\ {\text { a. Which of the two gases exerts the greater partial pressure? }} \\ {\text { b. The molecules or atoms of which gas will have the gressure? }} \\ {\text { velocity? }}\end{array}\end{equation}
\begin{equation}\begin{array}{l}{\text { c. The molecules of which gas will have the greater average kinetic }} \\ {\text { energy? }} \\ {\text { d. If a small hole were opened in the flask, which gas would effuse }} \\ {\text { more quickly? }}\end{array}\end{equation}

Dalton Hilovsky

Numerade Educator

01:02

Problem 73

Calculate the root mean square velocity and kinetic energy of $\mathrm{F}_{2}, \mathrm{Cl}_{2}$and $\mathrm{Br}_{2}$ at 298 $\mathrm{K}$ . Rank the three halogens with respect to their rate of effusion.

Sisi Gao

Numerade Educator

13:37

Problem 74

Calculate the root mean square velocity and kinetic energy of CO,
$\mathrm{CO}_{2},$ and $\mathrm{SO}_{3}$ at 298 $\mathrm{K}$ . Which gas has the greatest velocity? The greatest kinetic energy? The greatest effusion rate?

Matthew Bamidele

Numerade Educator

01:36

Problem 75

We obtain uranium- 235 from $U-238$ by fluorinating the uranium to form UF $_{6}($ which is a gas) and then taking advantage of the different rates of effusion and diffusion for compounds containing the two isotopes. Calculate the ratio of effusion rates for $^{238} \mathrm{UF}_{6}$ and $^{235} \mathrm{UF}_{6}$ . The atomic mass of $\mathrm{U}-235$ is 235.054 amu, and that of $\mathrm{U}-238$ is 238.051 amu.

Dalton Hilovsky

Numerade Educator

03:52

Problem 76

Calculate the ratio of effusion rates for Ar and Kr.

Matthew Bamidele

Numerade Educator

04:43

Problem 77

A sample of neon effuses from a container in 76 seconds. The same
amount of an unknown noble gas requires 155 seconds. Identify
the gas.

Noah Barguez-Arias

Numerade Educator

06:52

Problem 78

A sample of $\mathrm{N}_{2} \mathrm{O}$ effuses from a container in 42 seconds. How long
will it take the same amount of gaseous $\mathrm{I}_{2}$ to effuse from the same
container under identical conditions?

Matthew Bamidele

Numerade Educator

00:42

Problem 79

This graph shows the distribution of molecular velocities for two different molecules $(A$ and $B)$ at the same temperature. Which molecule has the higher molar mass? Which molecule has the higher rate of effusion?

Sisi Gao

Numerade Educator

03:21

Problem 80

This graph shows the distribution of molecular velocities for the same
molecule at two different temperatures $\left(T_{1} and T_{2}\right) .$ Which temperature
is greater? Explain.

Matthew Bamidele

Numerade Educator

02:03

Problem 81

Consider the chemical reaction:
$$\mathrm{C}(s)+\mathrm{H}_{2} \mathrm{O}(g) \longrightarrow \mathrm{CO}(g)+\mathrm{H}_{2}(g)$$
How many liters of hydrogen gas are formed from the complete reaction of 15.7 $\mathrm{g} \mathrm{C}^{2}$ Assume that the hydrogen gas is collected at a pressure of 1.0 atm and a temperature of 355 $\mathrm{K}$ .

Dalton Hilovsky

Numerade Educator

06:51

Problem 82

Consider the chemical reaction:
$$2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2 \mathrm{H}_{2}(g)+\mathrm{O}_{2}(g)$$
What mass of $\mathrm{H}_{2} \mathrm{O}$ is required to form 1.4 $\mathrm{L}$ of $\mathrm{O}_{2}$ at a temperature of 315 $\mathrm{K}$ and a pressure of 0.957 $\mathrm{atm}$ ?

Matthew Bamidele

Numerade Educator

03:37

Problem 83

$\mathrm{CH}_{3} \mathrm{OH}$ can be synthesized by the reaction:
What volume of $\mathrm{H}_{2}$ gas (in L), at 748 $\mathrm{mm} \mathrm{Hg}$ and $86^{\circ} \mathrm{C},$ is required to synthesize 25.8 $\mathrm{g} \mathrm{CH}_{3} \mathrm{OH}$ ? How many liters of CO gas, measured under the same conditions, are required?

Dalton Hilovsky

Numerade Educator

02:50

Problem 84

Oxygen gas reacts with powdered aluminum according to the reaction:
$$_{4} \mathrm{Al}(s)+3 \mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{Al}_{2} \mathrm{O}_{3}(s)$$
What volume of $\mathrm{O}_{2}$ gas (in $\mathrm{L} ),$ measured at 782 $\mathrm{mm} \mathrm{Hg}$ and $25^{\circ} \mathrm{C}$ completely reacts with 53.2 $\mathrm{g} \mathrm{Al}$ ?

Dalton Hilovsky

Numerade Educator

03:16

Problem 85

Automobile air bags inflate following serious impacts, which trigger the
chemical reaction:
$$2 \mathrm{NaN}_{3}(s) \longrightarrow 2 \mathrm{Na}(s)+3 \mathrm{N}_{2}(g)$$
If an automobile air bag has a volume of $11.8 \mathrm{L},$ what mass of $\mathrm{NaN}_{3}$ $(\mathrm{in} \mathrm{g})$ is required to fully inflate the air bag upon impact? Assume STP conditions.

Dalton Hilovsky

Numerade Educator

03:28

Problem 86

Lithium reacts with nitrogen gas according to the reaction:
$$6 \mathrm{Li}(s)+\mathrm{N}_{2}(g) \longrightarrow 2 \mathrm{Li}_{3} \mathrm{N}(s)$$
What mass of lithium (in g) reacts completely with 58.5 $\mathrm{mL}$ of $\mathrm{N}_{2}$ gas at STP?

Matthew Bamidele

Numerade Educator

05:13

Problem 87

Hydrogen gas (a potential future fuel) can be formed by the reaction
of methane with water according to the equation:
$$\mathrm{CH}_{4}(g)+\mathrm{H}_{2} \mathrm{O}(g) \longrightarrow \mathrm{CO}(g)+3 \mathrm{H}_{2}(g)$$
In a particular reaction, 25.5 $\mathrm{L}$ of methane gas (at a pressure of 732
torr and a temperature of $25^{\circ} \mathrm{C} )$ mixes with 22.8 $\mathrm{L}$ of water vapor $(\mathrm{at}$ a pressure of 702 torr and a temperature of $125^{\circ} \mathrm{C} )$ . The reaction produces 26.2 $\mathrm{L}$ of hydrogen gas at STP. What is the percent yield of the reaction?

Dalton Hilovsky

Numerade Educator

04:02

Problem 88

Ozone is depleted in the stratosphere by chlorine from $\mathrm{CF}_{3} \mathrm{Cl}$ according to this set of equations:
$$\begin{array}{c}{\mathrm{CF}_{3} \mathrm{Cl}+\mathrm{UV} \text { light } \longrightarrow \mathrm{CF}_{3}+\mathrm{Cl}} \\ {\mathrm{Cl}+\mathrm{O}_{3} \longrightarrow \mathrm{ClO}+\mathrm{O}_{2}} \\ {\mathrm{O}_{3}+\mathrm{UV} \operatorname{light} \longrightarrow \mathrm{O}_{2}+\mathrm{O}} \\ {\mathrm{ClO}+\mathrm{O} \longrightarrow \mathrm{Cl}+\mathrm{O}_{2}}\end{array}$$
What total volume of ozone at a pressure of 25.0 $\mathrm{mm} \mathrm{Hg}$ and a tem-
perature of 225 $\mathrm{K}$ is destroyed when all of the chlorine from 15.0 $\mathrm{g}$ of
$\mathrm{CF}_{3} \mathrm{Cl}$ goes through ten cycles of the above reactions?

Dalton Hilovsky

Numerade Educator

04:36

Problem 89

Chlorine gas reacts with fluorine gas to form chlorine trifluoride.
$$\mathrm{Cl}_{2}(g)+3 \mathrm{F}_{2}(g) \longrightarrow 2 \mathrm{ClF}_{3}(g)$$
A 2.00 -L reaction vessel, initially at 298 $\mathrm{K}$ , contains chlorine gas at a
partial pressure of 337 $\mathrm{mm} \mathrm{Hg}$ and fluorine gas at a partial pressure of
729 $\mathrm{mm} \mathrm{Hg}$ . Identify the limiting reactant and determine the theoretical
yield of $\mathrm{ClF}_{3}$ in grams.

Dalton Hilovsky

Numerade Educator

04:58

Problem 90

Carbon monoxide gas reacts with hydrogen gas to form methanol.
$$\mathrm{CO}(g)+2 \mathrm{H}_{2}(g) \longrightarrow \mathrm{CH}_{3} \mathrm{OH}(g)$$
A $1.50-$ L reaction vessel, initially at 305 $\mathrm{K}$ , contains carbon monoxide gas at a partial pressure of 232 $\mathrm{mmH} \mathrm{g}$ and hydrogen gas at a partial pressure of 397 $\mathrm{mm} \mathrm{H} \mathrm{g} .$ Identify the limiting reactant and determine the theoretical yield of methanol in grams.

Dalton Hilovsky

Numerade Educator

00:29

Problem 91

Which postulate of the kinetic molecular theory breaks down under conditions of high pressure? Explain.

Sisi Gao

Numerade Educator

03:12

Problem 92

Which postulate of the kinetic molecular theory breaks down under conditions of low temperature? Explain.

Matthew Bamidele

Numerade Educator

02:12

Problem 93

Use the van der Waals equation and the ideal gas equation to calculate
the volume of 1.000 mol of neon at a pressure of 500.0 atm and a
temperature of 355.0 $\mathrm{K}$ . Explain why the two values are different.
(Hint: One way to solve the van der Waals equation for $V$ is to use
successive approximations. Use the ideal gas law to get a preliminary
estimate for $V .$ .

Aadit Sharma

Numerade Educator

08:57

Problem 94

Use the van der Waals equation and the ideal gas equation to calculate
the pressure exerted by 1.000 mol of $\mathrm{Cl}_{2}$ in a volume of 5.000 $\mathrm{L}$ at a temperature of 273.0 $\mathrm{K}$ . Explain why the two values are different.

Matthew Bamidele

Numerade Educator

04:16

Problem 95

Pennies that are currently being minted are composed of zinc coated
with copper. A student determines the mass of a penny to be 2.482 $\mathrm{g}$
and then makes several scratches in the copper coating (to expose the underlying zinc). The student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the HCl (the copper remains undissolved):
$$\mathrm{Zn}(s)+2 \mathrm{HCl}(a q) \longrightarrow \mathrm{H}_{2}(g)+\mathrm{ZnCl}_{2}(a q)$$
The student collects the hydrogen produced over water at $25^{\circ} \mathrm{C}$ . The
collected gas occupies a volume of 0.899 $\mathrm{L}$ at a total pressure of 791
mmHg. Calculate the percent zinc (by mass) in the penny. (Assume that all the Zn in the penny dissolves.)

Dalton Hilovsky

Numerade Educator

06:27

Problem 96

A 2.85 -g sample of an unknown chlorofluorocarbon decomposes and
produces 564 $\mathrm{mL}$ of chlorine gas at a pressure of 752 $\mathrm{mm} \mathrm{Hg}$ and a temperature of 298 $\mathrm{K}$ . What is the percent chlorine (by mass) in the unknown chlorofluorocarbon?

Matthew Bamidele

Numerade Educator

00:47

Problem 97

The mass of an evacuated $255-\mathrm{mL}$ flask is 143.187 $\mathrm{g} .$ The mass of the
flask filled with 267 torr of an unknown gas at $25^{\circ} \mathrm{C}$ is 143.289 $\mathrm{g}$ .
Calculate the molar mass of the unknown gas.

Sisi Gao

Numerade Educator

06:16

Problem 98

A 118 -mL flask is evacuated and found to have a mass of 97.129 $\mathrm{g}$ .
When the flask is filled with 768 torr of helium gas at $35^{\circ} \mathrm{C},$ it has a
mass of 97.171 $\mathrm{g}$ . Is the helium gas pure?

Matthew Bamidele

Numerade Educator

09:49

Problem 99

A gaseous hydrogen and carbon containing compound is decomposed
and found to contain 82.66$\%$ carbon and 17.34$\%$ hydrogen by mass.
The mass of 158 $\mathrm{mL}$ of the gas, measured at 556 $\mathrm{mm} \mathrm{Hg}$ and $25^{\circ} \mathrm{C},$ is
0.275 $\mathrm{g} .$ What is the molecular formula of the compound?

Dr. Satish Ingale

Numerade Educator

03:52

Problem 100

A gaseous hydrogen-and-carbon containing compound is decomposed
and found to contain 85.63$\% \mathrm{C}$ and 14.37$\%$ by mass. The mass of 258 $\mathrm{mL}$ of the gas, measured at STP, is 0.646 $\mathrm{g} .$ What is the molecular
formula of the compound?

Eugene Schneider

University of Minnesota - Twin Cities

03:35

Problem 101

Consider the reaction:
$$2 \mathrm{NiO}(s) \longrightarrow 2 \mathrm{Ni}(s)+\mathrm{O}_{2}(g)$$
If $\mathrm{O}_{2}$ is collected over water at $40.0^{\circ} \mathrm{C}$ and a total pressure of 745 $\mathrm{mm} \mathrm{Hg},$ what volume of gas is collected for the complete reaction of 24.78 $\mathrm{g}$ of $\mathrm{NiO}^{2}$

Dalton Hilovsky

Numerade Educator

06:37

Problem 102

Consider the reaction:
$$2 \mathrm{Ag}_{2} \mathrm{O}(s) \longrightarrow 4 \mathrm{Ag}(s)+\mathrm{O}_{2}(g)$$
If this reaction produces 15.8 $\mathrm{g}$ of $\mathrm{Ag}(s),$ what total volume of gas can be collected over water at a temperature of $25^{\circ} \mathrm{C}$ and a total pressure of
752 $\mathrm{mm} \mathrm{Hg}$ ?

Matthew Bamidele

Numerade Educator

01:04

Problem 103

When hydrochloric acid is poured over potassium sulfide, 42.9 $\mathrm{mL}$ of
hydrogen sulfide gas is produced at a pressure of 752 torr and $25.8^{\circ} \mathrm{C}$ .
Write an equation for the gas-evolution reaction and determine how
much potassium sulfide (in grams) reacted.

Sisi Gao

Numerade Educator

06:00

Problem 104

Consider the reaction:
$$2 \mathrm{SO}_{2}(g)+\mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{SO}_{3}(g)$$

a. If 285.5 $\mathrm{mL}$ of $\mathrm{SO}_{2}$ reacts with 158.9 $\mathrm{mL}$ of $\mathrm{O}_{2}$ (both measured at 315 $\mathrm{K}$ and 50.0 $\mathrm{mm} \mathrm{Hg}$ , what is the limiting reactant and the theoretical yield of $\mathrm{SO}_{3}$ ?

b. If 187.2 $\mathrm{mL}$ of $\mathrm{SO}_{3}$ is collected (measured at 315 $\mathrm{K}$ and 50.0 $\mathrm{mmHg}$ ) what is the percent yield for the reaction?

Matthew Bamidele

Numerade Educator

02:49

Problem 105

Ammonium carbonate decomposes upon heating according to the balanced equation:
$$\left(\mathrm{NH}_{4}\right)_{2} \mathrm{CO}_{3}(s) \longrightarrow 2 \mathrm{NH}_{3}(g)+\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)$$
Calculate the total volume of gas produced at $22^{\circ} \mathrm{C}$ and 1.02 atm by the
complete decomposition of 11.83 $\mathrm{g}$ of ammonium carbonate.

Dalton Hilovsky

Numerade Educator

10:11

Problem 106

Ammonium nitrate decomposes explosively upon heating according to
the balanced equation:
$$2 \mathrm{NH}_{4} \mathrm{NO}_{3}(s) \longrightarrow 2 \mathrm{N}_{2}(g)+\mathrm{O}_{2}(g)+4 \mathrm{H}_{2} \mathrm{O}(g)$$
Calculate the total volume of gas (at $125^{\circ} \mathrm{C}$ and 748 $\mathrm{mm} \mathrm{Hg} )$ produced by the complete decomposition of 1.55 $\mathrm{kg}$ of ammonium nitrate.

Matthew Bamidele

Numerade Educator

01:00

Problem 107

Olympic cyclists fill their tires with helium to make them lighter. Calculate the mass of air in an air-filled tire and the mass of helium in a helium-filled tire. What is the mass difference between the two? Assume that the volume of the tire is 855 $\mathrm{mL}$ , that it is filled to a total pressure of 125 psi, and that the temperature is $25^{\circ} \mathrm{C}$ . Also, assume an average molar mass for air of 28.8 $\mathrm{g} / \mathrm{mol} .$

Sisi Gao

Numerade Educator

08:40

Problem 108

In a common classroom demonstration, a balloon is filled with air and submerged in liquid nitrogen. The balloon contracts as the gases within the balloon cool. Suppose a balloon initially contains 2.95 of air at a temperature of $25.0^{\circ} \mathrm{C}$ and a pressure of 0.998 atm. Calculate the expected volume of the balloon upon cooling to $-196^{\circ} \mathrm{C}$ (the boiling point of liquid nitrogen). When the demonstration is carried out, the actual volume of the balloon decreases to 0.61 $\mathrm{L}$ . How does the observed volume of the balloon compare to your calculated value? Explain the difference.

Matthew Bamidele

Numerade Educator

01:28

Problem 109

Gaseous ammonia is injected into the exhaust stream of a coal-burning
power plant to reduce the pollutant $\mathrm{NO}$ to $\mathrm{N}_{2}$ according to the reaction:
$$4 \mathrm{NH}_{3}(g)+4 \mathrm{NO}(g)+\mathrm{O}_{2}(g) \longrightarrow 4 \mathrm{N}_{2}(g)+6 \mathrm{H}_{2} \mathrm{O}(g)$$
Suppose that the exhaust stream of a power plant has a flow rate of
335 $\mathrm{L} / \mathrm{s}$ at a temperature of 955 $\mathrm{K}$ , and that the exhaust contains a partial pressure of $\mathrm{NO}$ of 22.4 torr. What should be the flow rate of ammonia delivered at 755 torr and 298 $\mathrm{K}$ into the stream to react completely with the $\mathrm{NO}$ if the ammonia is 65.2$\%$ pure (by volume)?

Sisi Gao

Numerade Educator

03:48

Problem 110

The emission of $\mathrm{NO}_{2}$ by fossil fuel combustion can be prevented by
injecting gaseous urea into the combustion mixture. The urea reduces
NO (which oxidizes in air to form $\mathrm{NO}_{2}$ ) according to the reaction:
$$\begin{array}{r}{2 \mathrm{CO}\left(\mathrm{NH}_{2}\right)_{2}(g)+4 \mathrm{NO}(g)+\mathrm{O}_{2}(g) \longrightarrow} \\ {4 \mathrm{N}_{2}(g)+2 \mathrm{CO}_{2}(g)+4 \mathrm{H}_{2} \mathrm{O}(g)}\end{array}$$
Suppose that the exhaust stream of an automobile has a flow rate of
2.55 $\mathrm{L} / \mathrm{s}$ at 655 $\mathrm{K}$ and contains a partial pressure of NO of 12.4 torr. What total mass of urea is necessary to react completely with the NO
formed during 8.0 hours of driving?

Eugene Schneider

University of Minnesota - Twin Cities

01:42

Problem 111

An ordinary gasoline can measuring 30.0 $\mathrm{cm}$ by 20.0 $\mathrm{cm}$ by 15.0 $\mathrm{cm}$ is evacuated with a vacuum pump. Assuming that virtually all of the air
can be removed from inside the can, and that atmospheric pressure is
14.7 psi, what is the total force (in pounds) on the surface of the can?
Do you think that the can will withstand the force?

Aadit Sharma

Numerade Educator

13:17

Problem 112

Twenty-five milliliters of liquid nitrogen (density $=0.807 \mathrm{g} / \mathrm{mL}$ ) is
poured into a cylindrical container with a radius of 10.0 $\mathrm{cm}$ and a
length of 20.0 $\mathrm{cm}$ . The container initially contains only air at a pressure of 760.0 $\mathrm{mm} \mathrm{Hg}$ (atmospheric pressure) and a temperature of 298
$\mathrm{K} .$ If the liquid nitrogen completely vaporizes, what is the total force
(in lb) on the interior of the container at 298 $\mathrm{K}$ ?

Matthew Bamidele

Numerade Educator

01:15

Problem 113

A 160.0 -L helium tank contains pure helium at a pressure of 1855 psi and a temperature of 298 $\mathrm{K}$ . How many 3.5 - helium balloons will the helium in the tank fill? (Assume an atmospheric pressure of 1.0 atm and a temperature of 298 $\mathrm{K}$ .

Sisi Gao

Numerade Educator

05:19

Problem 114

An $11.5-\mathrm{mL}$ sample of liquid butane (density $=0.573 \mathrm{g} / \mathrm{mL} )$ is evaporated in an otherwise empty container at a temperature of $28.5^{\circ} \mathrm{C}$ . The pressure in the container following evaporation is 892 torr. What is the volume of the container?

Matthew Bamidele

Numerade Educator

00:53

Problem 115

A scuba diver creates a spherical bubble with a radius of 2.5 $\mathrm{cm}$ at a
depth of 30.0 $\mathrm{m}$ where the total pressure (including atmospheric pressure) is 4.00 atm. What is the radius of the bubble when it reaches the surface of the water? (Assume that the atmospheric pressure is 1.00 atm and the temperature is 298 $\mathrm{K} .$ )

Sisi Gao

Numerade Educator

10:25

Problem 116

A particular balloon can be stretched to a maximum surface area of
1257 $\mathrm{cm}^{2} .$ The balloon is filled with 3.0 L of helium gas at a pressure of
755 torr and a temperature of 298 $\mathrm{K}$ . The balloon is then allowed to rise in the atmosphere. If the atmospheric temperature is 273 $\mathrm{K}$ , at what
pressure will the balloon burst? (Assume the balloon is a sphere.)

Matthew Bamidele

Numerade Educator

02:17

Problem 117

A catalytic converter in an automobile uses a palladium or platinum catalyst (a substance that increases the rate of a reaction without being consumed by the reaction) to convert carbon monoxide gas to carbon diaxide according to the reaction.
$$2 \mathrm{CO}(g)+\mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{CO}_{2}(g)$$
A chemist researching the effectiveness of a new catalyst combines a $2.0 :$
1.0 mole ratio mixture of carbon monoxide and oxygen gas (respectively)
over the catalyst in a $2.45-\mathrm{L}$ flask at a total pressure of 745 torr and a temperature of $552^{\circ} \mathrm{C}$ When the reaction is complete, the pressure in
the flask has dropped to 552 torr. What percentage of the carbon monoxide was converted to carbon dioxide?

David Collins

Numerade Educator

06:36

Problem 118

A quantity of $\mathrm{N}_{2}$ occupies a volume of 1.0 $\mathrm{L}$ at 300 $\mathrm{K}$ and 1.0 $\mathrm{atm}$ . The gas expands to a volume of 3.0 $\mathrm{L}$ as the result of a change in both temperature and pressure. Find the density of the gas at these new conditions.

Shahina -

Numerade Educator

01:29

Problem 119

A mixture of $\mathrm{CO}(g)$ and $\mathrm{O}_{2}(g)$ in a $1.0-\mathrm{L}$ container at $1.0 \times 10^{3} \mathrm{K}$ has a total pressure of 2.2 $\mathrm{atm.}$ After some time the total pressure falls to 1.9 atm as the result of the formation of $\mathrm{CO}_{2}$ . Determine the mass (in grams) of $\mathrm{CO}_{2}$ that forms.

Sisi Gao

Numerade Educator

13:02

Problem 120

The radius of a xenon atom is $1.3 \times 10^{-8} \mathrm{cm} . \mathrm{A} 100-\mathrm{mL}$ . flask is filled with $\mathrm{Xe}$ at a pressure of 1.0 atm and a temperature of 273 $\mathrm{K}$ . Calculate the fraction of the volume that is occupied by Xe atoms. (Hint: The
atoms are spheres.)

Matthew Bamidele

Numerade Educator

02:19

Problem 121

A natural gas storage tank is a cylinder with a moveable top whose volume can change only as its height changes. Its radius remains fixed. The height of the cylinder is 22.6 $\mathrm{m}$ on a day when the temperature is $22^{\circ} \mathrm{C}$ .The next day the height of the cylinder increases to 23.8 $\mathrm{m}$ when the gas expands because of a heat wave. Find the temperature on the second day, assuming that the pressure and amount of gas in the storage tank have
not changed.

Adriano Chikande

Numerade Educator

03:06

Problem 122

A mixture of 8.0 $\mathrm{g} \mathrm{CH}_{4}$ and 8.0 $\mathrm{g} \mathrm{Xe}$ is placed in a container, and the total pressure is found to be 0.44 atm. Determine the partial pressure of $\mathrm{CH}_{4} .$

Dalton Hilovsky

Numerade Educator

00:31

Problem 123

A steel container of volume 0.35 $\mathrm{L}$ can withstand pressures up to 88 $\mathrm{atm}$
before exploding. What mass of helium can be stored in this container at
299 $\mathrm{K}$ ?

Sisi Gao

Numerade Educator

08:26

Problem 124

Binary compounds of alkali metals and hydrogen react with water to liberate $\mathrm{H}_{2}(g) .$ The $\mathrm{H}_{2}$ from the reaction of a sample of $\mathrm{NaH}$ with an excess of water fills a volume of 0.490 $\mathrm{L}$ above the water. The temperature of the gas is $35^{\circ} \mathrm{C},$ and the total pressure is 758 $\mathrm{mm} \mathrm{Hg} .$ Determine the mass of $\mathrm{H}_{2}$ liberated and the mass of NaH that reacted.

Matthew Bamidele

Numerade Educator

02:43

Problem 125

In a given diffusion apparatus, 15.0 $\mathrm{mL}$ of HBr gas diffused in 1.0 $\mathrm{min.}$
In the same apparatus and under the same conditions, 20.3 $\mathrm{mL}$ of an unknown gas diffused in 1.0 $\mathrm{min}$ . The unknown gas is a hydrocarbon. Find its molecular formula.

Aadit Sharma

Numerade Educator

04:52

Problem 126

A sample of $\mathrm{N}_{2} \mathrm{O}_{3}(g)$ has a pressure of 0.017 atm. The temperature
(in K) is doubled, and the $\mathrm{N}_{2} \mathrm{O}_{3}$ undergoes complete decomposition to $\mathrm{NO}_{2}(g)$ and $\mathrm{NO}(g) .$ Find the total pressure of the mixture of gases
assuming constant volume and no additional temperature change.

Shahina -

Numerade Educator

07:46

Problem 127

When 0.583 g of neon is added to an 800 $\mathrm{cm}^{3}$ bulb containing a sample
of argon, the total pressure of the gases is 1.17 atm at a temperature of
295 $\mathrm{K}$ . Find the mass of the argon in the bulb.

Shahina -

Numerade Educator

18:17

Problem 128

A gas mixture composed of helium and argon has a density of 0.670 $\mathrm{g} / \mathrm{L}$ at
755 $\mathrm{mm} \mathrm{Hg}$ and 298 $\mathrm{K} .$ What is the composition of the mixture by volume?

Shahina -

Numerade Educator

00:56

Problem 129

A gas mixture contains 75.2$\%$ nitrogen and 24.8$\%$ krypton by mass.
What is the partial pressure of krypton in the mixture if the total pressure is 745 mmHg?

Sisi Gao

Numerade Educator

09:45

Problem 130

A 10 -L container is filled with 0.10 mol of $\mathrm{H}_{2}(g)$ and heated to 3000
$\mathrm{K},$ causing some of the $\mathrm{H}_{2}(g)$ to decompose into $\mathrm{H}(g) .$ The total pressure is 3.0 atm. Find the partial pressure of the H(g) that forms from $\mathrm{H}_{2}$ at this temperature. (Assume two significant figures for the temperature.)

Matthew Bamidele

Numerade Educator

07:23

Problem 131

A mixture of $\mathrm{NH}_{3}(g)$ and $\mathrm{N}_{2} \mathrm{H}_{4}(g)$ is placed in a sealed container at 300 $\mathrm{K}$ . The total pressure is 0.50 atm. The container is heated to 1200 $\mathrm{K}$ , at which time both substances decompose completely according to the equations: $2 \mathrm{NH}_{3}(g) \longrightarrow \mathrm{N}_{2}(g)+3 \mathrm{H}_{2}(g)$;
$\mathrm{N}_{2} \mathrm{H}_{4}(g) \longrightarrow \mathrm{N}_{2}(g)+2 \mathrm{H}_{2}(g) .$ After decomposition is complete, the total pressure at 1200 $\mathrm{K}$ is 4.5 atm. Find the percent of $\mathrm{N}_{2} \mathrm{H}_{4}(g)$ in the original mixture. (Assume two significant figures for the temperature.)

Tracy Tourville

Numerade Educator

05:44

Problem 132

A quantity of CO gas occupies a volume of 0.48 $\mathrm{L}$ at 1.0 $\mathrm{atm}$ and 275
$\mathrm{K} .$ The pressure of the gas is lowered and its temperature is raised until its volume is 1.3 $\mathrm{L} .$ Determine the density of the CO under the new conditions.

Matthew Bamidele

Numerade Educator

10:01

Problem 133

When $\mathrm{CO}_{2}(g)$ is put in a sealed container at 701 $\mathrm{K}$ and a pressure of
10.0 atm and is heated to 1401 $\mathrm{K}$ , the pressure rises to 22.5 atm. Some
of the $\mathrm{CO}_{2}$ decomposes to $\mathrm{CO}$ and $\mathrm{O}_{2}$ . Calculate the mole percent of $\mathrm{CO}_{2}$ that decomposes.

Shahina -

Numerade Educator

08:16

Problem 134

The world burns approximately $3.5 \times 10^{12}$ kg of fossil fuel per year.
Use the combustion of octane as the representative reaction and determine the mass of carbon dioxide (the most significant greenhouse gas) formed per year. The current concentration of carbon dioxide in the atmosphere is approximately 394 ppm (by volume). By what percentage does the concentration increase each year due to fossil fuel combustion? Approximate the average properties of the entire atmosphere by assuming that the atmosphere extends from sea level to 15 $\mathrm{km}$ and that it has an average pressure of 381 torr and average temperature of 275 $\mathrm{K}$ . Assume Earth is a perfect sphere with a radius of 6371 $\mathrm{km} .$

Adriano Chikande

Numerade Educator

10:26

Problem 135

The atmosphere slowly oxidizes hydrocarbons in a number of steps that
eventually convert the hydrocarbon into carbon dioxide and water. The
overall reaction of a number of such steps for methane gas is:
$$\begin{array}{c}{\mathrm{CH}_{4}(g)+5 \mathrm{O}_{2}(g)+5 \mathrm{NO}(g) \longrightarrow} \\ {\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)+5 \mathrm{NO}_{2}(g)+2 \mathrm{OH}(g)}\end{array}$$
Suppose that an atmospheric chemist combines 155 $\mathrm{mL}$ of methane at
$\mathrm{STP}, 885 \mathrm{mL}$ of oxygen at $\mathrm{STP},$ and 55.5 $\mathrm{mL}$ of $\mathrm{NO}$ at STP in a $2.0-\mathrm{L}$ flask. The flask stands for several weeks at 275 $\mathrm{K}$ If the reaction reaches
90.0$\%$ of completion $(90.0 \%$ of the limiting reactant is cansumed), what
is the partial pressure of each of the reactants and products in the flask at
275 $\mathrm{K}$ ? What is the total pressure in the flask?

David Collins

Numerade Educator

06:17

Problem 136

Two identical balloons are filled to the same volume, one with air and one with helium. The next day, the volume of the air-filled balloon has decreased by 5.0$\%$ . By what percent has the volume of the helium-filled balloon decreased? (Assume that the air is four-fifths nitrogen and one-fifth oxygen, and that the temperature did not change.)

Matthew Bamidele

Numerade Educator

02:38

Problem 137

A mixture of $\mathrm{CH}_{4}(g)$ and $\mathrm{C}_{2} \mathrm{H}_{6}(g)$ has a total pressure of 0.53 atm. Just enough $\mathrm{O}_{2}(g)$ is added to the mixture to bring about its complete com-
bustion to $\mathrm{CO}_{2}(g)$ and $\mathrm{H}_{2} \mathrm{O}(g)$ . The total pressure of the two product gases is found to be 2.2 atm. Assuming constant volume and temperature, find the mole fraction of $\mathrm{CH}_{4}$ in the mixture.

Adriano Chikande

Numerade Educator

06:53

Problem 138

A sample of $\mathrm{C}_{2} \mathrm{H}_{2}(g)$ has a pressure of 7.8 $\mathrm{kP}$ . After some time, a portion of it reacts to form $\mathrm{C}_{6} \mathrm{H}_{6}(g) .$ The total pressure of the mixture of gases is then 3.9 $\mathrm{kP}$ a. Assume the volume and the temperature do not
change. What fraction of $\mathrm{C}_{2} \mathrm{H}_{2}(g)$ has undergone reaction?

Matthew Bamidele

Numerade Educator

00:41

Problem 139

When the driver of an automobile applies the brakes, the passengers
are pushed toward the front of the car, but a helium balloon is pushed
toward the back of the car. Upon forward acceleration, the passengers
are pushed toward the back of the car, but the helium balloon is
pushed toward the front of the car, Why?

Sisi Gao

Numerade Educator

00:38

Problem 140

Suppose that a liquid is 10 times denser than water. If you were to sip
this liquid at sea level using a straw, what is the maximum length your
straw can be?

Eugene Schneider

University of Minnesota - Twin Cities

03:10

Problem 141

The generic reaction occurs in a closed container:
$$\mathrm{A}(g)+2 \mathrm{B}(g) \longrightarrow 2 \mathrm{C}(g)$$
A reaction mixture initially contains 1.5 $\mathrm{L}$ of $\mathrm{A}$ and 2.0 $\mathrm{L}$ of B. Assuming that the volume and temperature of the reaction mixture remain
constant, what is the percent change in pressure if the reaction goes to
completion?

Dalton Hilovsky

Numerade Educator

02:22

Problem 142

One mole of nitrogen and one mole of neon are combined in a closed
container at STP. How big is the container?

Matthew Bamidele

Numerade Educator

04:47

Problem 143

Exactly equal amounts (in moles) of gas A and gas $\mathrm{B}$ are combined in $\mathrm{a} 1-\mathrm{L}$ container at room temperature. Gas $\mathrm{B}$ has a molar mass that is twice that of gas A. Which statement is true for the mixture of gases and why?
a. The molecules of gas $\mathrm{B}$ have greater kinetic energy than those of gas A.
b. Gas B has a greater partial pressure than gas A.
c. The molecules of gas $B$ have a greater average velocity than those of gas A.
d. Gas $\mathrm{B}$ makes a greater contribution to the average density of the mixture than gas A.

Ronald Prasad

Numerade Educator

04:55

Problem 144

Which gas would you expect to deviate most from ideal behavior
under conditions of low temperature: $F_{2}, \mathrm{Cl}_{2},$ or $\mathrm{Br}_{2}$ ? Explain.

Matthew Bamidele

Numerade Educator

01:03

Problem 145

The volume of a sample of a fixed amount of gas is decreased from 2.0 $\mathrm{L}$
to 1.0 $\mathrm{L} .$ The temperature of the gas in kelvins is then doubled. What is
the final pressure of the gas in terms of the initial pressure?

Sisi Gao

Numerade Educator

04:07

Problem 146

Which gas sample has the greatest volume at STP?
a. 10.0 $\mathrm{g} \mathrm{Kr}$
b. 10.0 $\mathrm{g} \mathrm{Xe}$
c. 10.0 $\mathrm{g} \mathrm{He}$

Matthew Bamidele

Numerade Educator

05:17

Problem 147

Draw a depiction of a gas sample, as described by kinetic molecular theory, containing equal molar amounts of helium, neon, and krypton. Use different color dots to represent each element. Give each atom a "tail" to represent its velocity relative to the others in the mixture.

Prashant Bana

Numerade Educator