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Name ________KEY_______________ Period _______

CRHS Academic Chemistry

Unit 11 - Gas Laws

Practice Problems

Due Date Assignment On-Time (100) Late (70)

______ 11.1 ________ ________

______ 11.2 ________ ________

______ 11.3 ________ ________

______ 11.4 ________ ________

______ Warm-Up ________

______ EC ________

Notes, Homework, Exam Reviews and Their KEYS located on CRHS Academic Chemistry Website: https://cincochem.pbworks.com

https://cincochem.pbworks.com/

of 12 Unit 11 HW

Dalton’s Law

Ideal Gas Law

Combined Gas Law

Boyle’s Law

Charles’s Law

Gay-Lussac’s Law

STP

Temperature: 273K = 0°C

Pressure: 101.3 kPa = 1.0 atm = 760 mmHg

K = °C + 273

𝑃1𝑉1 = 𝑃2𝑉2

𝑃1𝑉1

𝑇1=

𝑃2𝑉2

𝑇2

𝑃𝑉 = 𝑛𝑅𝑇

𝑉1

𝑇1=

𝑉2

𝑇2

𝑃1

𝑇1=

𝑃2

𝑇2

𝑃𝑇𝑜𝑡𝑎𝑙 = 𝑃1 + 𝑃2 + 𝑃3 …

Unit 11 HW of 12

WARM-UPS

Day 1

Day 2

Day 3

Day 4

Day 5

Day 6

of 12 Unit 11 HW

11.1 GASES AND THE FOUR VARIABLES

For numbers 1-3, CIRCLE the italicized term that best completes the sentence.

1. During gas particle collision, kinetic energy…

( increases / decreases / stays the same).

2. As temperature increases, kinetic energy…


3. As the speed of gas molecules increases, kinetic energy…


4. Why are gases able to be compressed?

Most of volumes of gas is empty space

5. The SI unit for volume is ____L_____________, pressure is _____kPa_________, and temperature is _K________.

6. Convert the following.

a. 24 °C _297_ K

b. 58 °C _331_ K

c. 54 K _-219_ °C

d. 324 K _51__ °C

7. Convert the following.

a. 1.01 atm __767.6 mmHg

b. 98.4 kPa _0.97_ atm

c. 0.950 atm _96.2_ kPa

d. 104.5 kPa _784_ mmHg

8. What is absolute zero? Temp at which all particle movement stops_________________

Unit 11 HW of 12 9. You have a sample of a gas in a sealed, rigid (cannot be stretched or enlarged) cylinder. If you INCREASE the

temperature of the cylinder, what happens to…

a. …the kinetic energy of the gas molecules.

__increases as temp increases_________________________________________

__________________________________________________________________

b. …The pressure exerted by the gas molecules on the walls of the container.

Increases because the particles hit the wall with greater speed and force and they

hit more often as the speed increases_________________________________________

c. …The speed of the gas molecules.

_increases___________________________________________________

__________________________________________________________________

d. …The number of collisions of gas molecules with other gas molecules.

increases__________________________________________________________

__________________________________________________________________

10. What is the total pressure (in mmHg) exerted by a sample of gases containing 319 mmHg H2, 201 mmHg N2, and 0.6

mmHg O2?

Pt = 319 mmHg + 201 mmHg + 0.6 mm Hg = 520.6 mmHg = 521 mmHg

11. If the total pressure of a mixture of O2, N2, and H2 is 902 mmHg, what is the pressure of O2 if there pressure of N2 is 355 mmHg N2 and H2 is 255 mmHg?

902 mm Hg = PO2 + 355 + 255 PO2 = 319 mmHg

of 12 Unit 11 HW

11.2 IDEAL GAS LAW 1. Determine the temperature (in °C ) of 2.49 moles of gas contained in a 1.00 L vessel at a pressure of 143 kPa.

PV = nRT

143 𝑥 1.06 = 2.49 𝑥 8.31 𝑥 𝑇 𝑇 =143𝑥1.06

2.49𝑥8.31= 6.91 𝐾 6.91𝐾 − 273 = −266𝑜𝐶

2. What is the pressure (in kPa) of a 0.108 mol sample of helium gas at 20.0 C if its volume is 0.505 L?

PV = nRT where R = 8.31 and T = 20.0 + 273 = 293K

𝑃 𝑥 0.505 = 0.108 𝑥 8.31 𝑥 293 𝑃 =0.108𝑥8.31𝑥293

0.505= 521 𝑘𝑃𝑎

3. Calculate the number of moles of gas that occupy a 3.45 L container at a pressure of 150 kPa and a temperature of

45.6 C.

PV = nRT where R = 8.31 and T = 45.6 + 273 = 318.6 K

150 𝑥 3.45 = 𝑛 𝑥 8.31𝑥 318.6 𝑛 =150𝑥3.45

8.31𝑥318.6 𝑛 = 0.195 𝑚𝑜𝑙

4. If 0.2804 mol of methane gas (CH4) is introduced into a 2.00 L container at 35.0 C, what is the pressure (atm) in the

container?

PV = nRT where R = 0.0821 and T = 35 + 273 = 308 K

𝑃 𝑥 2.00 = 0.2804 𝑥 0.0821 𝑥 308 𝑃 =0.2804 𝑥 0.0821𝑥308

2.00 𝑃 = 3.55 𝑎𝑡𝑚

Unit 11 HW of 12

5. A 2.00 L flask is filled with propane gas (C3H8) at 101.3 kPa and –15.0 C. What is the mass (in grams) of the propane

in the flask? (Hint: Convert moles to grams!)

Answer = 4.17 g C3H8

SHOW WORK!

6. Determine the pressure inside a television picture tube with a volume of 3.50 L that contains 2.00 x 10 –5 grams of

nitrogen gas at 22.0 C. (Hint: Convert grams to moles!

Answer = 5.00x10-4 kPa

SHOW WORK!

7. How many grams of oxygen gas must be present in a 2.00 L container at 35 C if the pressure is 212 kPa?

Answer = 5.30 g O2

SHOW WORK!

of 12 Unit 11 HW

11.3 COMBINED GAS LAW

For Questions 1-4, circle the correct answer 1. Assuming volume and temperature are held constant in a sealed container, what happens to pressure when more

molecules of gas are injected?

A – Decreases B. Increases C. Stays the Same D. Cannot Determine

2. When the volume of a container is increased, the pressure inside the cylinder …….


3. As a gas heats up the average kinetic energy of its molecules will ….


4. Assuming pressure and temperature are held constant in a balloon, what happens to volume as gas molecules are

removed?


5. A helium filled balloon at sea level has a volume of 2.10 L at 0.998 atm and 36 C. If it is released and rises to an

elevation at which the pressure is 0.900 atm and the temperature is 28 C, what will be the new volume of the

balloon?

6. At 20.0 C and 1.00 atm pressure, a sample of gas occupies 0.03 L. If the temperature is increased to 30.0 C and the

entire sample is transferred to a 0.02 L container, what will be the gas pressure inside the container?

Unit 11 HW of 12

7. A sample of air in a syringe exerts a pressure of 1.02 atm at a temperature of 22.0 C. The syringe is then placed in a

boiling water bath at 100.0 C. The pressure of the air is increased to 1.23 atm by pushing the plunger in, which

reduces the volume to 0.224 L. What was the original volume of air?

8. An unopened cold 2.00 L soda bottle contains 46.0 mL of gas confined at a pressure of 1.30 atm at a temperature of

5.0 C. If the bottle is dropped into a lake and sinks to a depth at which the pressure is 2.85 atm and temperature is

2.09 C, what will the volume of the gas in the bottle be? (NOTE: Be sure to convert mL to L)

9. A sample of unknown pressure occupies 0.766 L at a temperature of 298 K. The same sample of gas is then tested

under known conditions and has a pressure of 32.6 kPa and occupies 0.644 L at 303 K. What was the original

pressure of the gas?

10. A gas at 110 kPa and 30.0 C fills a flexible container with an initial volume of 2.00 L. If the temperature is raised to

80.0 C and the pressure is increased to 440 kPa, what is the new volume?

of 12 Unit 11 HW

11.4 INDIVIDUAL GAS LAWS Read each question. Circle the gas law that applies to the problem. Then, solve for the missing variable. 1. If a basketball has a volume 2.50 L and a temperature of 25 °C, what will its new volume be if it is left in the cold at

temperature of – 10.0 °C? Assume that pressure remains constant.

( Boyle’s / Charles’s / Gay – Lussac’s )

2. If a balloon has a pressure of 1.30 atm and a temperature of 100.0 °C. If volume remains constant, and its

temperature is raised to 215 °C, what will the new pressure be? ( Boyle’s / Charles’s / Gay- Lussac’s )

3. If a balloon has a volume of 3.00 L and a pressure of 600.0 mmHg, what will its pressure be if its volume decreases to

2.00 L? Assume that temperature remains constant. ( Boyle’s / Charles’s / Gay-Lussac’s )

4. If a ball has an initial temperature of 315 K, what will its final temperature be if the pressure is changed from 1.20

atm to 13.2 atm? Assume that volume remains constant.


Unit 11 HW of 12 5. A ball has a volume of 3.50 L and a pressure of 450.0 kPa. If temperature remains constants, how large will the

volume be if we increase the pressure to 550.0 kPa?


6. If a balloon has a volume of 3.20 L at 273 K, what will its volume be at 473 K? Pressure is held constant.


of 12 Unit 11 HW

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