How do you change the volume of a gas?

Question

How do you change the volumes of gases from the conditions given to the new conditions (assuming that the temperature and amount of gas is constant)?

For example, 1.15 x 10^3 cm3 at 75.2 kPa to 14.0 kPa?

Answer 1

Given conditions:

Volume: 1.15 x 10^3 cm3
Temperature: constant
Pressure: 75.2kPa

New conditions:

Volume: ?
Temperature: constant
Pressure: 14.0 kPa

Your variables in this problem are volume (V) and pressure (P). Temperature is not part of the equation since it is held constant.

This is a Boyle's Law Gas Problem:

P1 x V1 = P2 x V2

P1 is beginning pressure. V1 is beginning volume.
P2 is ending pressure. V2 is ending volume.

Rearrange your formula to isolate the variable you want (V2). You do this by dividing both sides of your equation by P2

V2 = P1V1/P2
Now, insert your numbers for your variables.

V2 = (75.2kPa) (1.15 x 10^3 cm3)/14.0 kPa

kPa will cancel leaving you only with cm3 as a unit.
Multiply your numerators and divid by your denominator. This will give you your new volume.

CHEMISTRY TEACHER

Answer 2

P1 x V2 = P2 x V2
V2=6.177 x 10^3

Answer 3

P1V1=P2V2
P1V1/P2=V2
(1.15 * 10^3 cm^3) (75.2 kPa)/(14.0 kPa) = 6.18 *10^3 cm^3

Answer 4

You have indicated a decrease in pressure, this would allow the gas to expand. It will expand to fill any container you allow it to be in.