5.16 use the relationship between pressure and kelvin temperature of a fixed mass of gas at constant volume

P1 / T1 = P2 / T1

Example: A container has a volume of 30 litres. It is filled with a gas at a pressure of 100 kPa and a temperature of 290 K. Find the new pressure (in kPa) if the temperature is increased to 315 K.

Step 1: rearrange the equation to isolate the unknown

The old pressure is P1
The old temperature is T1
The new pressure is P2 (this is what we are finding)
The new temperature is T2

if P1/T1=P2/T2 and we are looking for P2, we must rearrange the equation to...

P2 = (P1/T1) x T2

Step 2: substitute the known into the equation

P2 = (100 / 290) x 315

 = 109 kPa

NOTE: as we are asked to leave the new pressure in kPa, we do not need to convert it, if asked to leave the answer in Pa (and you have it in kPa) just multiply it by 100

Example credit: CGP