Question

At s.t.p., a certain mass of gas occupies a volume of 790 cm. Find the temperature at which the gas occupies 1000 cm and has a pressure of 726 mm Hg.

Answer 1

Let P1,V1 be the initial pressure,voloume and temparature of the gas at T1=273.15 and P2,V2 be the final pressure,voloume of tha gas T2 is the final temparature.

Use the combined gas law:

P1V1/T1 = P2V2/T2, where;

P1 = initial pressure = 760mmHg

V1 = initial volume = 790 cm

P2 = final pressure = 726mmHg

V2 = final volume = 1000cm

T1 = intial temperature = 273.15 K

T2=final temperature=?

Rearrange the equation for the combined gas law to isolate T2

T2 = P2V2T1/V1P1

T2 = (726mmHg·1000cm ·273.15k)/(790cm·760mmHg)

T2=330.15k

So the gas occupies 1000cm and has a pressure of 726 mmHg at temperature 330.15k