Boyle's Law Examples: 45 Problems with Answers

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Boyle's Law.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Chemistry.

Concept Recap

Boyle's law states that for a fixed amount of gas at constant temperature, pressure and volume are inversely related.

Squeeze a gas into less space and it pushes back harder.

Read the full concept explanation →

How to Use These Examples

Read the first worked example with the solution open so the structure is clear.
Try the practice problems before revealing each solution.
Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Boyle's Law starts by listing pressure, volume, temperature, amount, and which are held constant.

Common stuck point: Students often know a formula related to boyle's law but skip the recognition step: Am I comparing gas variables with units and temperature in kelvin, while holding the stated variables constant? That leads to a correct-looking substitution attached to the wrong chemical model.

Sense of Study hint: Ask: Am I comparing gas variables with units and temperature in kelvin, while holding the stated variables constant?

Worked Examples

Example 1

medium

A weather balloon at ground level holds

5\text{ L}

1\text{ atm}

. At altitude (same

T

) the volume is

20\text{ L}

. What is the pressure at altitude?

Answer

0.25 atm

First step

P_2 = P_1 V_1 / V_2 = 1 \times 5 / 20 = 0.25\text{ atm}

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Example 2

medium

A scuba tank holds

12\text{ L}

200\text{ atm}

. At constant

T

, what volume would that gas occupy at

1\text{ atm}

Example 3

medium

P_1 = 1.0\text{ atm}

V_1 = 22.4\text{ L}

. At constant

T

, what pressure forces the gas into

5.6\text{ L}

Example 4

hard

20\text{ L}

container at

5\text{ atm}

is connected via a valve to an evacuated

30\text{ L}

container. After opening the valve at constant

T

, find the final pressure throughout.

Example 5

hard

A diver at

40\text{ m}

depth (total

5\text{ atm}

) exhales a

0.50\text{ L}

bubble. At constant

T

, what volume does the bubble reach at the surface (

1\text{ atm}

Example 6

hard

PV = 24\text{ atm}\cdot \text{L}

at temperature

T

. The gas is held in a

4\text{ L}

container. Calculate

P

and verify

PV

is constant if

V

becomes

6\text{ L}

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy

Using P1V1 = P2V2 with P1=2 atm, V1=3 L, V2=6 L, find P2.

Example 2

easy

P1=4 atm, V1=2 L, P2=2 atm. Find V2.

Example 3

easy

In Boyle's law, what is held constant?

Example 4

easy

If pressure on a gas increases at constant temperature, what happens to its volume?

Example 5

easy

P1=1 atm, V1=10 L, V2=5 L. Find P2.

Example 6

easy

P1=3 atm, V1=4 L, P2=6 atm. Find V2.

Example 7

easy

Is the product P times V constant in Boyle's law?

Example 8

easy

Both pressure values are given as 760 mmHg and 1520 mmHg with V1=8 L. Find V2 (units already match).

Example 9

medium

A gas at 1.5 atm occupies 8 L. It is compressed to 3 L at constant temperature. Find the new pressure.

Example 10

medium

A balloon holds 2 L at 1 atm. It rises to where pressure is 0.5 atm (constant T). Find the new volume.

Example 11

medium

A gas at 2 atm in 5 L is moved to a 2 L container at the same temperature. Find the pressure.

Example 12

medium

Convert units: P1=2 atm, V1=3 L, P2=1520 mmHg. Find V2 (1 atm = 760 mmHg).

Example 13

medium

A syringe holds 50 mL at 1 atm. The plunger is pushed to 20 mL at constant temperature. Find the pressure.

Example 14

medium

A gas occupies 12 L at 0.5 atm. At what pressure will it occupy 4 L at constant temperature?

Example 15

medium

A gas in a 6 L cylinder at 5 atm leaks into a connected 4 L cylinder, total 10 L, at constant T. Find the final pressure.

Example 16

medium

A gas at 2.5 atm occupies 6 L. It is compressed to 2 L at constant temperature. Find the new pressure.

Example 17

medium

A gas at 1 atm in 20 L is compressed at constant temperature to 2.5 atm. Find the new volume.

Example 18

challenge

A gas at 8 atm in 2 L is expanded to 16 L at constant temperature. Then it is compressed back to 4 L. Find the final pressure.

Example 19

challenge

A gas obeys P1V1 = P2V2. If its volume is reduced to one-fourth, by what factor does pressure change?

Example 20

challenge

A diver's lungs hold 6 L at 3 atm underwater. Rising to the surface (1 atm) at constant T, what volume would the gas reach?

Example 21

easy

P_1 = 1.5\text{ atm}

V_1 = 4\text{ L}

V_2 = 2\text{ L}

. Find

P_2

Example 22

easy

P_1 = 2\text{ atm}

V_1 = 6\text{ L}

P_2 = 4\text{ atm}

. Find

V_2

Example 23

easy

A gas at

5\text{ atm}

1\text{ L}

expands at constant

T

10\text{ L}

. What is the new pressure?

Example 24

easy

If a gas's volume triples at constant

T

, by what factor does pressure change?

Example 25

easy

P_1 = 100\text{ kPa}

V_1 = 2\text{ L}

V_2 = 4\text{ L}

. Find

P_2

Example 26

medium

A gas at

760\text{ mmHg}

occupies

3\text{ L}

. It is compressed to

1.5\text{ L}

at constant

T

. Find the new pressure in mmHg.

Example 27

medium

A piston compresses gas from

10\text{ L}

1\text{ atm}

2.5\text{ L}

at constant

T

. Find the new pressure.

Example 28

medium

Convert

V_1

V_1 = 500\text{ mL}

1.2\text{ atm}

V_2 = 1.5\text{ L}

. Find

P_2

(constant

T

Example 29

medium

A gas at

2\text{ atm}

fills

10\text{ L}

. Volume is doubled at constant

T

. What is the new

PV

product compared to the original?

Example 30

medium

4\text{ L}

gas at

3\text{ atm}

flows into a connected

6\text{ L}

vessel (total

10\text{ L}

) at constant

T

. Find the final pressure.

Example 31

medium

A gas at

0.75\text{ atm}

has

V_1 = 8\text{ L}

. After compression at constant

T

V_2 = 2\text{ L}

. Find

P_2

Example 32

medium

P

on a

V

-vs-

1/P

graph (constant

T

) is plotted, what shape appears?

Example 33

medium

A gas at

5\text{ atm}

holds

4\text{ L}

. It is decompressed to

1\text{ atm}

at constant

T

. Find the new volume.

Example 34

hard

A gas is compressed from

1.0\text{ atm}

and

50\text{ L}

25\text{ L}

. At constant

T

, then compressed further to

10\text{ L}

. What is the final pressure?

Example 35

hard

P_1 = 1\text{ atm}

V_1 = 1\text{ L}

. If pressure increases by

20\%

at constant

T

, what is the new volume?

Example 36

hard

Mixed units:

P_1 = 380\text{ mmHg}

V_1 = 8\text{ L}

P_2 = 1\text{ atm}

. Find

V_2

(constant

T

Example 37

hard

A gas at

P_1

and

V_1 = 10\text{ L}

is compressed to

V_2 = 2.5\text{ L}

. The pressure increases by

6.0\text{ atm}

. Find

P_1

(constant

T

Example 38

hard

A gas at

1.6\text{ atm}

and

25\text{ L}

is compressed to

V_2

, raising pressure to

4.0\text{ atm}

at constant

T

. Find

V_2

Example 39

challenge

5\text{ L}

rigid vessel at

4\text{ atm}

is connected via valve to an evacuated rigid

V_x\text{ L}

vessel. After equilibration at constant

T

, pressure is

1\text{ atm}

throughout. Find

V_x

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Related Concepts

Gas Laws Charles's Law

Background Knowledge

These ideas may be useful before you work through the harder examples.

gas laws