Chemistry A Molecular Approach

Nivaldo J. Tro

Chapter 5 Gases - all with Video Answers

Educators

Chapter Questions

00:38

Problem 1

What is pressure? What causes pressure?

Eugene Schneider

University of Minnesota - Twin Cities

02:29

Problem 2

Explain what happens when you inhale. What forces air into your lungs?

Adriano Chikande

Numerade Educator

02:29

Problem 3

Explain what happens when you exhale. What forces air out of your lungs?

Adriano Chikande

Numerade Educator

04:05

Problem 4

What are some common units of pressure? List these in order of smallest to largest unit.

Matthew Bamidele

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

07:18

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 and also state which variables must be kept constant.

Matthew Bamidele

Numerade Educator

01:06

Problem 7

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

Eugene Schneider

University of Minnesota - Twin Cities

08:45

Problem 8

Explain why scuba divers should never hold their breath as they ascend to the surface.

Matthew Bamidele

Numerade Educator

03:25

Problem 9

Why is it impossible to breathe air through an extralong snorkel (greater than a couple of meters) while swimming under water?

Adriano Chikande

Numerade Educator

04:13

Problem 10

Explain why hot air balloons float above the ground, and why the second story of a two-story home is often warmer than the ground story.

Matthew Bamidele

Numerade Educator

01:22

Problem 11

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

Eugene Schneider

University of Minnesota - Twin Cities

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

04:18

Problem 14

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

Kevin Chimex

Numerade Educator

01:05

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?

Eugene Schneider

University of Minnesota - Twin Cities

01:05

Problem 16

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

Eugene Schneider

University of Minnesota - Twin Cities

02:17

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?

Kevin Chimex

Numerade Educator

01:36

Problem 18

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

Kevin Chimex

Numerade Educator

03:48

Problem 19

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

Kevin Chimex

Numerade Educator

04:29

Problem 20

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

Kevin Chimex

Numerade Educator

01:56

Problem 21

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?

Eugene Schneider

University of Minnesota - Twin Cities

04:29

Problem 22

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

Matthew Bamidele

Numerade Educator

01:39

Problem 23

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

Eugene Schneider

University of Minnesota - Twin Cities

02:15

Problem 24

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

Eugene Schneider

University of Minnesota - Twin Cities

00:36

Problem 25

What are the main atmospheric pollutants and their sources? What are the trends in the levels of these pollutants over U.S. cities?

Morgan Thompson

Numerade Educator

00:28

Problem 26

Explain why ozone is a pollutant in the lower atmosphere but a necessary component of our upper atmosphere.

Morgan Thompson

Numerade Educator

02:12

Problem 27

What compounds are blamed for the depletion of stratospheric ozone? How do these compounds deplete ozone, and what is being done to prevent further depletion?

Anitha Mary

Numerade Educator

02:02

Problem 28

Why does an ozone hole form over the South Pole every October?

Wan Deng

Numerade Educator

03:33

Problem 29

The pressure in Denver, Colorado (elevation $5280 \mathrm{ft}$, averages about $24.9$ in $\mathrm{Hg}$. Convert this pressure to
a. atm
b. $\mathrm{mmHg}$
c. psi
d. $\mathrm{Pa}$

Dalton Hilovsky

Numerade Educator

02:53

Problem 30

The pressure on top of $\mathrm{Mt}$. Everest averages about $235 \mathrm{mmHg}$. Convert this pressure to
a. torr
b. psi
$\mathbf{c}$ in $\mathrm{Hg}$
d. atm

Nicole Mabante

Numerade Educator

02:39

Problem 31

The North American record for highest recorded barometric pressure is $31.85$ in $\mathrm{Hg}$, set in 1989 in Northway, Alaska. Convert this pressure to
a. $\mathrm{mmHg}$
b. atm
c. tom
d. $\mathrm{kPa}$ (kilopascals)

Dalton Hilovsky

Numerade Educator

02:20

Problem 32

The world record for lowest pressure (at sea level) was $652.5 \mathrm{mmHg}$ recorded inside Typhoon Tip on October 12, 1979 , in the Western Pacific Ocean. Convert this pressure to
a. torr
b. atm
c. in $\mathrm{Hg}$
d. psi

Dalton Hilovsky

Numerade Educator

01:07

Problem 33

Given a barometric pressure of $762.4 \mathrm{mmHg}$, calculate the pressure of each gas sample as indicated by the manometer.

Sisi Gao

Numerade Educator

08:07

Problem 34

Given a barometric pressure of $751.5 \mathrm{mmHg}$, calculate the pressure of each gas sample as indicated by the manometer.

Matthew Bamidele

Numerade Educator

02:18

Problem 35

A sample of gas has an initial volume of $5.6 \mathrm{~L}$ at a pressure of $735 \mathrm{mmHg}$. If the volume of the gas is increased to $9.4 \mathrm{~L}$, what will the pressure be?

Kevin Chimex

Numerade Educator

02:01

Problem 36

A sample of gas has an initial volume of $13.9 \mathrm{~L}$ at a pressure of $1.22 \mathrm{~atm}$. If the sample is compressed to a volume of $10.3 \mathrm{~L}$, what will its pressure be?

Matthew Bamidele

Numerade Educator

01:41

Problem 37

A $48.3-\mathrm{mL}$ 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 38

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

02:45

Problem 39

A balloon contains $0.158$ mol of gas and has a volume of $2.46 \mathrm{~L}$. If an additional $0.113$ mol of gas is added to the balloon
(at the same temperature and pressure), what will its final volume be?

Bailey Mccarthy Riley

Numerade Educator

02:13

Problem 40

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

Matthew Bamidele

Numerade Educator

00:26

Problem 41

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

Sisi Gao

Numerade Educator

04:13

Problem 42

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

Matthew Bamidele

Numerade Educator

02:25

Problem 43

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

Kevin Chimex

Numerade Educator

01:31

Problem 44

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

Eugene Schneider

University of Minnesota - Twin Cities

00:24

Problem 45

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

01:22

Problem 46

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

Eugene Schneider

University of Minnesota - Twin Cities

04:08

Problem 47

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 $12.0^{\circ} \mathrm{C}$. Driving on a hot day, the tire warms to $65.0{ }^{\circ} \mathrm{C}$ and its volume expands to $12.2 \mathrm{~L}$. 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.)

Kevin Chimex

Numerade Educator

02:52

Problem 48

A weather balloon is inflated to a volume of $28.5 \mathrm{~L}$ at a pressure of $748 \mathrm{mmHg}$ 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 $385 \mathrm{mmHg}$ 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

01:29

Problem 49

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 $742 \mathrm{mmHg}$ ?

Nicole Mabante

Numerade Educator

08:24

Problem 50

A $1.0-\mathrm{L}$ 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 $1.0 \mathrm{~atm}$, 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

03:29

Problem 51

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 $295 \mathrm{~K} ?$ 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 $295 \mathrm{~K} ?$

Kevin Chimex

Numerade Educator

02:24

Problem 52

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. At $298 \mathrm{~K}$, to what 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.)

Adriano Chikande

Numerade Educator

View

Problem 53

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

Jean Gephart

Numerade Educator

01:36

Problem 54

This picture represents a sample of gas at a pressure of $1 \mathrm{~atm}, \mathrm{a}$ 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 increased to $250^{\circ} \mathrm{C}$. What would happen to the pressure?

Dalton Hilovsky

Numerade Educator

00:48

Problem 55

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

Sisi Gao

Numerade Educator

01:58

Problem 56

A sample of nitrogen gas in a $1.75-\mathrm{L}$ container exerts a pressure of $1.35 \mathrm{~atm}$ 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 57

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 58

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

Matthew Bamidele

Numerade Educator

01:51

Problem 59

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

Ly Tran

Numerade Educator

03:41

Problem 60

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

02:47

Problem 61

An experiment shows that 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?

Shazia Naz

Numerade Educator

03:38

Problem 62

An experiment shows that a $113-\mathrm{mL}$ gas sample has a mass of $0.171 \mathrm{~g}$ at a pressure of $721 \mathrm{mmHg}$ and a temperature of $32^{\circ} \mathrm{C}$. What is the molar mass of the gas?

Madeline Currie

Numerade Educator

00:45

Problem 63

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 64

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 $753 \mathrm{mmHg}$. Find the molar mass of the gas.

Dalton Hilovsky

Numerade Educator

02:01

Problem 65

A gas mixture contains each of the following gases at the indicated partial pressures: $\mathrm{N}_{2}, 215$ torr; $\mathrm{O}_{2}, 102$ torr; and $\mathrm{He}$, 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

02:36

Problem 66

A gas mixture with a total pressure of $745 \mathrm{mmHg}$ contains each of the following gases at the indicated partial pressures: $\mathrm{CO}_{2}$, $125 \mathrm{mmHg}$ : 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 $12.0$ - $\mathrm{L}$ sample of this mixture at $273 \mathrm{~K}$ ?

Nicole Mabante

Numerade Educator

07:34

Problem 67

A $1.20-\mathrm{g}$ sample of dry ice is added to a $755-\mathrm{mL}$ flask containing nitrogen gas at a temperature of $25.0{ }^{\circ} \mathrm{C}$ and a pressure of $725 \mathrm{mmHg}$. 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?

Shahina -

Numerade Educator

02:31

Problem 68

A $275-\mathrm{mL}$ flask contains pure helium at a pressure of 752 torr. A second 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 are the partial pressures of each gas and the total pressure?

Eugene Schneider

University of Minnesota - Twin Cities

01:15

Problem 69

A gas mixture contains $1.25 \mathrm{~g} \mathrm{~N}_{2}$ 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

05:09

Problem 70

What is the mole fraction of oxygen gas in air (see Table 5.3)? What volume of air contains $10.0 \mathrm{~g}$ of oxygen gas at $273 \mathrm{~K}$ and $1.00 \mathrm{~atm} ?$

Matthew Bamidele

Numerade Educator

01:12

Problem 71

The hydrogen gas formed in a chemical reaction is collected over water at $30.0^{\circ} \mathrm{C}$ at a total pressure of $732 \mathrm{mmHg}$. 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 72

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 $5.45 \mathrm{~L}$ 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

04:08

Problem 73

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 hydrochloric acid can get to the zinc). The reaction between the acid and the zinc is $2 \mathrm{H}^{+}(a q)+\mathrm{Zn}(s) \longrightarrow$ $\mathrm{H}_{2}(\mathrm{~g})+\mathrm{Zn}^{2+}(a q)$. When the zinc in a certain penny dissolves, the total volume of gas collected over water at $25^{\circ} \mathrm{C}$ was $0.951$
$L$ at a total pressure of $748 \mathrm{mmHg}$. What mass of hydrogen gas was collected?

Adriano Chikande

Numerade Educator

04:28

Problem 74

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

00:37

Problem 75

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 $15.7 \mathrm{~g}$ C? Assume that the hydrogen gas is collected at a pressure of $1.0 \mathrm{~atm}$ and a temperature of $355 \mathrm{~K}$.

Sisi Gao

Numerade Educator

06:51

Problem 76

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

01:20

Problem 77

$\mathrm{CH}_{3} \mathrm{OH}$ can be synthesized by the reaction:
$$
\mathrm{CO}(g)+2 \mathrm{H}_{2}(g) \longrightarrow \mathrm{CH}_{3} \mathrm{OH}(g)
$$
What volume of $\mathrm{H}_{2}$ gas (in $\mathrm{L}$ ), 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 $\mathrm{CO}$ gas, measured under the same conditions, is required?

Sisi Gao

Numerade Educator

06:42

Problem 78

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 $782 \mathrm{mmHg}$ and $25{ }^{\circ} \mathrm{C}$, completely reacts with $53.2$ g Al?

Shahina -

Numerade Educator

01:05

Problem 79

Automobile air bags inflate following a serious impact. The impact triggers 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 $\mathrm{NaN}_{3}$ (in $\mathrm{g}$ ) is required to fully inflate the air bag upon impact? Assume STP conditions.

Nicole Mabante

Numerade Educator

03:28

Problem 80

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

00:59

Problem 81

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 (measured at a pressure of 732 torr and a temperature of $25^{\circ} \mathrm{C}$ ) mixes with $22.8 \mathrm{~L}$ of water vapor (measured 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?

Sisi Gao

Numerade Educator

04:24

Problem 82

Ozone is depleted in the stratosphere by chlorine from $\mathrm{CF}_{3} \mathrm{Cl}$ according to the set of equations:
What total volume of ozone at a pressure of $25.0 \mathrm{mmHg}$ and a temperature 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?

Eugene Schneider

University of Minnesota - Twin Cities

View

Problem 83

Consider a 1.0-L sample of helium gas and a 1.0-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 would have the faster rate of effusion?

David Collins

Numerade Educator

01:30

Problem 84

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

Eugene Schneider

University of Minnesota - Twin Cities

01:02

Problem 85

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 86

Calculate the root mean square velocity and kinetic energy of $\mathrm{CO}, \mathrm{CO}_{2}$, 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 87

We obtain uranium- 235 from $\mathrm{U}-238$ by fluorinating the uraniiim to form $\mathrm{UF}_{6}$ (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 $235.054 \mathrm{amu}$
and that of U-238 is $238.051$ amu.

Dalton Hilovsky

Numerade Educator

03:52

Problem 88

Calculate the ratio of effusion rates for Ar and Kr.

Matthew Bamidele

Numerade Educator

04:43

Problem 89

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 90

A sample of $\mathrm{N}_{2} \mathrm{O}$ effuses from a container in 42 seconds. How long would 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 91

The 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 would have the higher rate of effusion?

Sisi Gao

Numerade Educator

03:21

Problem 92

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

Matthew Bamidele

Numerade Educator

01:59

Problem 93

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

Kevin Chimex

Numerade Educator

03:12

Problem 94

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

Matthew Bamidele

Numerade Educator

02:12

Problem 95

Use the van der Waals equation and the ideal gas equation to calculate the volume of $1.000 \mathrm{~mol}$ of neon at a pressure of $500.0 \mathrm{~atm}$ 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 96

Use the van der Waals equation and the ideal gas equation to calculate the pressure exerted by $1.000 \mathrm{~mol}$ of $\mathrm{Cl}_{2}$ in a volume of $5.000 \mathrm{I}$. at a temperature of $2730 \mathrm{~K}$ Fxplain why the two values are different.

Matthew Bamidele

Numerade Educator

01:34

Problem 97

Modern pennies 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 $\mathrm{HCl}$ (the copper remains undissolved):
$$
\mathrm{Zn}(s)+2 \mathrm{HCl}(a q) \longrightarrow \mathrm{H}_{2}(g)+\mathrm{ZnCl}(a q)
$$
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 press?re of $791 \mathrm{mmHg}$. Calculate the percent zinc (by mass) in the penny. (Assume that all the $\mathrm{Zn}$ in the penny dissolves.)

David Collins

Numerade Educator

02:43

Problem 98

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

Eugene Schneider

University of Minnesota - Twin Cities

02:43

Problem 98

Eugene Schneider

University of Minnesota - Twin Cities

00:47

Problem 99

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 100

A $118-\mathrm{mL}$ 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 $97.171 \mathrm{~g}$. Was the helium gas pure?

Matthew Bamidele

Numerade Educator

22:58

Problem 101

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

Shahina -

Numerade Educator

17:02

Problem 102

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

Shahina -

Numerade Educator

01:00

Problem 103

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 $745 \mathrm{mmHg}$, what volume of gas will be collected for the complete reaction of $24.78 \mathrm{~g}$ of $\mathrm{NiO}$ ?

Sisi Gao

Numerade Educator

06:37

Problem 104

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 $752 \mathrm{mmHg}$ ?

Matthew Bamidele

Numerade Educator

01:04

Problem 105

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

01:04

Problem 106

Sisi Gao

Numerade Educator

02:49

Problem 107

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 108

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 $\left.748 \mathrm{~mm} \mathrm{Hg}\right)$ produced by the complete decomposition of $1.55 \mathrm{~kg}$ of ammonium nitrate.

Matthew Bamidele

Numerade Educator

01:00

Problem 109

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 $125 \mathrm{psi}$, 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

04:17

Problem 110

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 the balloon initially contains $2.95 \mathrm{~L}$ 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? Can you expain the difference?

Ronald Prasad

Numerade Educator

01:28

Problem 111

Gaseous ammonia can be injected into the exhaust stream of a coal-burning power plant to reduce the pollutant 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

12:44

Problem 112

The emission of $\mathrm{NO}_{2}$ by fossil fuel combustion can be prevented by injecting gaseous urea into the combustion mixture. The urea reduces $\mathrm{NO}$ (which oxidizes in air to form $\mathrm{NO}_{2}$ ) according to the reaction:
$\begin{aligned} 2 \mathrm{CO}\left(\mathrm{NH}_{2}\right)_{2}(g)+4 \mathrm{NO}(g)+\mathrm{O}_{2}(g) & \longrightarrow 4 \mathrm{~N}_{2}(g) \\ &+2 \mathrm{CO}_{2}(g)+4 \mathrm{H}_{2} \mathrm{O}(g) \end{aligned}$
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 $\mathrm{NO}$ of $12.4$ torr. What total mass of urea is necessary to react completely with the NO formed during $8.0$ hours of driving?

Matthew Bamidele

Numerade Educator

00:53

Problem 113

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 could withstand the force?

Sisi Gao

Numerade Educator

View

Problem 114

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

Susan Hallstrom

Numerade Educator

01:32

Problem 115

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

Aadit Sharma

Numerade Educator

05:19

Problem 116

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 117

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 $4.00 \mathrm{~atm}$. What is the radius of the bubble when it reaches the surface of the water? (Assume that the atmospheric pressure is $1.00 \mathrm{~atm}$ and the temperature is $298 \mathrm{~K}$.)

Sisi Gao

Numerade Educator

10:25

Problem 118

A particular balloon can be stretched to a maximum surface area of $1257 \mathrm{~cm}^{2}$. The balloon is filled with $3.0 \mathrm{~L}$ 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 to be in the shape of a sphere.)

Matthew Bamidele

Numerade Educator

01:42

Problem 119

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 dioxide 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-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?

Sisi Gao

Numerade Educator

06:36

Problem 120

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 121

A mixture of $\mathrm{CO}(\mathrm{g})$ and $\mathrm{O}_{2}(\mathrm{~g})$ 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 $\mathrm{CO}_{2}$. Find the mass (in grams) of $\mathrm{CO}_{2}$ that forms.

Sisi Gao

Numerade Educator

13:02

Problem 122

The radius of a xenon atom is $1.3 \times 10^{-8} \mathrm{~cm}$. A $100-\mathrm{mL}$ flask is filled with Xe at a pressure of $1.0 \mathrm{~atm}$ 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 123

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 124

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 $0.44 \mathrm{~atm}$. Find the partial pressure of $\mathrm{CH}_{4}$

Dalton Hilovsky

Numerade Educator

01:41

Problem 125

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

Aadit Sharma

Numerade Educator

08:26

Problem 126

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 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 $758 \mathrm{mmHg}$. Determine the mass of $\mathrm{H}_{2}$ liberated and the mass of NaH that reacted.

Matthew Bamidele

Numerade Educator

02:43

Problem 127

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 128

A sample of $\mathrm{N}_{2} \mathrm{O}_{3}(g)$ has a pressure of $0.017 \mathrm{~atm}$. The temperature (in $\mathrm{K}$ ) is then 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 129

When $0.583 \mathrm{~g}$ of neon is added to an $800-\mathrm{cm}^{3}$ bulb containing a sample of argon, the total pressure of the gases is found to be
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 130

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

Shahina -

Numerade Educator

00:56

Problem 131

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 $745 \mathrm{~mm} \mathrm{Hg}$ ?

Sisi Gao

Numerade Educator

03:09

Problem 132

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

Adriano Chikande

Numerade Educator

05:44

Problem 134

A quantity of $\mathrm{CO}$ 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 $1.3 \mathrm{~L}$. Find the density of the CO under the new conditions.

Matthew Bamidele

Numerade Educator

10:01

Problem 135

When $\mathrm{CO}_{2}(g)$ is put in a sealed container at $701 \mathrm{~K}$ and a pressure of $10.0 \mathrm{~atm}$ 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 136

The world burns approximately $9.0 \times 10^{12} \mathrm{~kg}$ 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 387 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

09:02

Problem 137

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
$\begin{aligned} \mathrm{CH}_{4}(g)+5 \mathrm{O}_{2}(g)+5 \mathrm{NO}(g) \longrightarrow & \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g) \\ &+5 \mathrm{NO}_{2}(g)+2 \mathrm{OH}(g) \end{aligned}$
Suppose that an atmospheric chemist combines $155 \mathrm{~mL}$ of methane at STP, 885 mL of oxygen at STP, and $55.5 \mathrm{~mL}$ of NO

Ronald Prasad

Numerade Educator

05:53

Problem 138

Two identical balloons are filled to the same volume, one with air and one with helium. The next day, the volume of the airfilled 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.)

Shahina -

Numerade Educator

02:38

Problem 139

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

Adriano Chikande

Numerade Educator

04:06

Problem 140

A sample of $\mathrm{C}_{2} \mathrm{H}_{2}(g)$ has a pressure of $7.8 \mathrm{kPa}$. 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 $3.9 \mathrm{kPa}$. Assume the volume and the temperature do not change. What fraction of $\mathrm{C}_{2} \mathrm{H}_{2}(g)$ has undergone reaction?

Shahina -

Numerade Educator

00:41

Problem 141

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

10:39

Problem 142

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

Matthew Bamidele

Numerade Educator

01:24

Problem 143

The 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 $2.0 \mathrm{~L}$ o. $\mathrm{B}$. 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?

David Collins

Numerade Educator

00:27

Problem 144

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

Eugene Schneider

University of Minnesota - Twin Cities

04:47

Problem 145

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

Ronald Prasad

Numerade Educator

04:55

Problem 146

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

Matthew Bamidele

Numerade Educator