Gases

A gas sample has a volume of$0.256 L$ with an unknown temperature. The same gas has a volume of $0.198 L$ when the temperature is $32°C$, with no change in the pressure or amount of gas. What was the initial temperature, in degrees Celsius, of the gas? 

Using the answer from problem $8.61$, how many grams of nitrogen are in Whitney's lungs at STP if the air contains $78\%$nitrogen?

Use the kinetic molecular theory of gases to explain each of the following:

a. Gases move faster at higher temperatures.

b. Gases can be compressed much more easily than liquids or solids.

c. Gases have low densities.

Identify the property of a gas that is measured in each of the following:

a. $350 K$

b. $125 mL$

c.  $2 g$ of ${\mathrm{O}}_2$

d.   $755 mm Hg$

Use the kinetic molecular theory of gases to explain each of the following:

1.  A container of nonstick cooking spray explodes when thrown into a fire.
2.  The air in a hot-air balloon is heated to make the balloon rise.
3.  You can smell the odor of cooking onions from far away.

Which of the following statements describe the pressure of a gas?
a. the force of the gas particles on the walls of the container
b. the number of gas particles in a container
c. $4.5L$ of helium gas
d. $750$ Torr
e. $28.8 Ib/i{n}^2$

Identify the property of a gas that is measured in each of the following:

1. $425 K$
   
2. $1.0 atm.$
   
3. $10.0 L$
   
4. $0.50$mole of $\mathrm{He}$
   

The air in a 5.00-L tank has a pressure of 1.20 atm. What is the final pressure, in atmospheres, when the air is placed in tanks that have the following volumes, if there is no change in temperature and amount of gas?

a. 1.00 L 

b. 2500. mL

c. 750. mL 

d. 8.00 L

Which of the following statement describes the pressure of a gas?
a. the temperature of the gas
b. the volume of the container
c. $3.0$ atm
d. $0.25$ mole of ${\mathrm{O}}_2$
e. $101$ kPa

An oxygen tank contains oxygen $\left(O_2\right)$ at a pressure of $2.00$ atm. What is the pressure in the tank in terms of the following units?
a. torr 

b. mmHg

On a climb up Mt. Whitney, the atmospheric pressure drops to $467$ mmHg. What is the pressure in terms of the following units?
a. atm 

b. torr

A I0.0-L balloon contains helium gas at a pressure of 655 mmHg. What is the final pressure, in millimeters of mercury, when the helium is placed in tanks that have the following volumes, if there is no change in temperature and amount of gas? 

a. 20.0 L 

b. 2.50 L

c. 13 800 mL 

d. 1250 mL

A sample of Ar gas has a volume of 5.40 L with an unknown pressure. The gas has a volume of 9.73 L when the pressure is 3.62 atm, with no change in temperature or amount of gas. What was the initial pressure, in atmospheres, of the gas?

A sample of Ne gas has a pressure of 654 mmHg with an unknown volume. The gas has a pressure of 345 mmHg when the volume is 495 mL, with no change in temperature or amount of gas. What was the initial volume, in milliliters, of the gas?

Cyclopropane, C₃H_6, is a general anesthetic. A 5.0-L sample has a pressure of 5.0 atm. What is the final volume, in liters, of this gas given to a patient at a pressure of 1.0 atm with no change in temperature and amount of gas?

A patient's oxygen tank holds 20.0 L of oxygen (0₂) at a pressure of 15.0 atm. What is the final volume, in liters, of this gas when it is released at a pressure of 1.00 atm with no change in temperature and amount of gas?

Use the words inspiration and expiration to describe the part of the breathing cycle that occurs as a result of each of the following:

a. The diaphragm contracts.

b. The volume of the lungs decreases.

c. The pressure within the lungs is less than that of the atmosphere.

Use the words inspiration and expiration to describe the part of the breathing cycle that occurs as a result of each of the following:

a. The diaphragm relaxes, moving up into the thoracic cavity.

b. The volume of the lungs expands.

c. The pressure within the lungs is higher than that of the atmosphere.

A gas at a pressure of $2.0$ atm is in a closed container. Indicate the changes (increases, decreases, does not change) in its volume when the pressure undergoes the following changes at the same temperature and amount of gas:
a. The pressure increases to $6.0$ atm
b. The pressure remains at $2.0$ atm
c. The pressure drops to $0.40$ atm

Why do scuba divers need to exhale air when they ascend to the surface of the water?

Why does a sealed bag of chips expand when you take it to a higher altitude?

A gas with a volume of 4.0 L is in a closed container. Indicate the changes (increases, decreases, does not change) in pressure when the volume undergoes the following changes at constant temperature and amount of gas:
a. The volume is compressed to $2.0$ L.
b. The volume expands to $12$ L.
c. The volume is compressed to $0.40$ L

A balloon is filled with helium gas. When each of the following
changes are made at constant temperature, which of the follow-
ing diagrams  (A, B, or C)  shows the final volume of the
balloon.

a. The balloon floats to a higher altitude where the outside pressure is lower.
b. The balloon is taken inside the house, but the atmospheric pressure does not change.
c. The balloon is put in a hyperbaric chamber in which the pressure is increased.

The air in a cylinder with a piston has a volume of $220$ mL and
a pressure of $650$ mmHg.
a. To obtain a higher pressure inside the cylinder at constant
temperature and amount of gas, would the cylinder change
as shown in A or B? Explain your choice.

b. If the pressure inside the cylinder increases to $1.2$ atm, what
is the final volume, in milliliters, of the cylinder? Complete
the following data table

A sample of nitrogen (N₂) has a volume of 50.0 L at a pressure of 760 mm Hg. What is the final volume, in liters, of the gas at each of the following pressures, if there is no change in temperature and amount of gas?

a. 725 mmHg 

b. 2.0 atm

c. 0.500 atm 

d. 850 Torr

A sample of methane  has a volume of $25$ mL at a pressure of $0.80$ atm. What is the final volume, in milliliters, of the gas at each of the following pressures, if there is no change in temperature and amount of gas?
a.$0.40$ atm

b. $2.00$ atm
c. $2500$ mmHg

d. $80.0$ torr

Select the diagram that shows the final volume of a balloon when each of the following changes are made when the pressure and amount of gas do not change: 

a. The temperature is changed from $100 K$ to $300 K$.

 b. The balloon is placed in a freezer. 

c. The balloon is first warmed and then returned to its starting temperature 

 A sample of neon initially has a volume of $2.50 L$ at $15 °C$. What final temperature, in degrees Celsius, is needed to change the volume of the gas to each of the following, if $P$ and $n$do not change? 

a. $5.00 L$

 b . $1250 mL$

 c. $7.50 L$

 d.$3550 mL$

A gas has a volume of$4.00 \mathrm{L}$ at $0 °\mathrm{C}.$ What final temperature, in degrees Celsius, is needed to change the volume of the gas to each of the following, if $P$and $n$ do not change?

a. $1.50 \mathrm{L}$

 b . $1200 \mathrm{mL}$ 

c. $10.0 \mathrm{L}$ 

d. $50.0 \mathrm{mL}$

A balloon contains$2500 \mathrm{mL}$of helium gas at $75 °C$. What is the final volume, in milliliters, of the gas when the temperature changes to each of the following, if $P$and n do not change? 

a. $55 °C$

b.$680. K$

c. $-25°C$

 d. $240. K$

Indicate whether the final volume of gas in each of the following is the same, larger, or smaller than the initial volume, if pressure and amount of gas do not change:
a. A volume of $505 mL$of air on a cold winter day at $15°C$ is breathed into the lungs, where body temperature is $37°C$
b. The heater used to heat the air in a hot-air balloon is turned off.
c. A balloon filled with helium at the amusement park is left in a car on a hot day.

A gas sample has a temperature of $22 °C$with an unknown volume. The same gas has a volume of $456 mL$ when the temperature is  $86°C$, with no change in the pressure or amount of gas. What was the initial volume, in milliliters, of the gas?

An air bubble has a volume of $0.500 L$ at $18°C$  What is the final volume, in liters, of the gas when the temperature changes to each of the following, if $P$  and $n$ do not change?
a. $0°C$
b. $425K$
c. $-12°C$
d. $575K$

Calculate the final pressure, in atmospheres, for each of the following, if $V$ and$n$ do not change:

 a. A gas with an initial pressure of $1.20 atm$ at$75 °C$ is cooled to $-32°C.$

b. A sample of $N$, with an initial pressure of $780. mmHg$ at $-75 °C$ is heated to$28 °C.$

Calculate the final temperature, in degrees Celsius, for each of the following, if $V , n$do not change:

a. A sample of xenon gas at $25°C$ and $740 mmHg$ is cooled to give a pressure of $620 mmHg$.

b. A tank of argon gas with a pressure of $0950 atm$ at $-18°C$ is heated to give a pressure of $1250 Torr.$

Calculate the final temperature, in degrees Celsius, for each of the following, if  $V, n$ do not change:

a. A sample of helium gas with a pressure of $250 Torr$ at $0°C$ is heated to give a pressure of $1500 Torr$.

b. A sample of air at   $40°C$ and $740 mmHg$ is cooled to give a pressure of $680 mmHg.$

A gas sample has a pressure of $744 mmHg$ when the temperature is $22°C$. What is the final temperature, in degrees Celsius, when the pressure is $766 mmHg$, with no change in the volume or amount of gas?

A gas sample has a pressure of $2.35 atm$ when the temperature is  $-15°C$. What is the final pressure, in atmospheres, when the temperature is $46°C$, with no change in the volume or amount of gas?

A tank contains isoflurane, an inhaled anesthetic, at a pressure of $1.8 atm$ and $5°C$. What is the pressure, in atmospheres, if the gas is warmed to a temperature of $22°C$, if $V , n$do not change?

Bacteria and viruses are inactivated by temperatures above $135°C$. An autoclave contains steam at $1.00 atm$ and $100 °C$. What is the pressure, in atmospheres, when the temperature of the steam in the autoclave reaches $135°C$if $V and n$do not change?

Calculate the final pressure, in millimeters of mercury, for each of the following, if $V$ and  $n$ do not change:
a. A gas with an initial pressure of $1200$ Torr at $155°C$ is cooled to $0°C$
b. A gas in an aerosol can at an initial pressure of $1.40 atm$ at $12°C$ is heated to $35°C$.

Rearrange the variable in the combined gas law to solve for $T_2$.

Rearrange the variable in the combined gas law to solve for $P_2$.

A $124 mL$ bubble of hot gas initially at $212 °C$ and $1.80 atm$ is emitted from an active volcano. What is the final temperature, in degrees Celsius, of the gas in the bubble outside the volcano if the final volume of the bubble is $138 mL$and the pressure is $0.800 atm$, if the amount of gas does not change?

A scuba diver $60 ft$ below the ocean surface inhales $50.0 mL$of compressed air from a ccuba tank at a pressure of $3.00 atm$ and a temperature of $8°C$. What is the final pressure of air, in atmospheres, in the lungs when the gas expands to $150.0 mL$ at a body temperature of $37 °C$, if the amount of gas does not change?

A sample of helium gas has a volume of $6.50L$ at a pressure of $845 mmHg$ and a temperature of $25°C$. What is the final pressure of the gas, in atmospheres, when the volume and temperature of the gas sample are changed to the following if the amount of gas does not change?

a. $1850 mL and 325 K$

b. $2.25 L and 12°C$

c. $12.8 L and 47°C$

A sample of argon gas has a volume of $735 mL$ at a pressure of $1.20 atm$ and a temperature of $112 °C$. What is the final volume of the gas, in milliliters, when the pressure and temperature of the gas sample are changed to the following if the amount of the gas does not change?

a. $658 mmHg and 281 K$

b. $0.55 atm and 75°C$

c. $15.4 atm and -15°C$

Use the molar volume to calculate each of the following at STP:

a. the number of moles of O₂ in 44.8 L of O₂  gas.

b. the volume in liters, occupied by 2.50 moles of N₂ gas.

c. the volume, in liters, occupied by 50.0 g of Ar gas.

d. the number of grams of H₂ in 16.20 mL of H₂ gas.

What happens to the volume of a bicycle tire or a basketball when you use an air pump to add air?

Sometimes when you blow up a balloon and release it, it flies around the room. What is happening to the air in the balloon and its volume?