What is the pressure of a 20.0-L, gas at 25 ◦C, if after compressing to a volume of 4.0 L its pressure is 55.0 atm at the same temperature?

The new volume will be

0.7 L

Explanation:

This is an example of Charles' law, sometimes called the temperature-volume law. It states that the volume of a gas is directly proportional to the Kelvin temperature, while pressure and amount are held constant.

The equation is

V

1

T

1

=

V

2

T

2

, where

V

is volume and

T

is temperature in Kelvins.

Known

V

1

=

0.5 L

T

1

=

20

∘

C

+

273.15

=

293 K

T

2

=

150

∘

C

+

273.15

=

423 K

Unknown

V

2

Solution

Rearrange the equation to isolate

V

2

. Substitute the known values into the equation and solve.

V

2

=

V

1

T

2

T

1

V

2

=

(

0.5

L

×

423

K

)

293

K

=

0.7 L

rounded to one significant figure

d

explanation: