Question

A 2.50 L gas sample at 25 degrees Celsius and a pressure of 95.3 kPa expands to a volume f 7.00 L the final pressure of the gas is 47.3 kPa what is the final temperature of the gas?

Answer 1

We can use here the combined gas law, relating the temperature, pressure, and volume of a gas with a constant quantity:

P1V1T1=P2V2T2

If you're using the ideal-gas equation, which we're NOT using here, you would have to convert each measurement into the appropriate units (L,K,atm,and mol). The only measurement that needs conversion here is temperature, from oC to K. (You will always convert temperature to Kelvin (absolute temperature) when using gas equations).

The Kelvin temperature is

K=20oC+273=293K

Let's rearrange the combined gas law to solve for the final temperature, T2:

T2=P2V2T1P1V1

Plugging in known values, we can find the final temperature:

T2=(56.7kPa)(8.00L)(293K)(86.7kPa)(3.50L)=438K

Lastly, we'll convert back from K to oC: