Question

If gas is cooled from 323.0K to 273K and the volume is kept constant, what final pressure would result if the original pressure was 750.0 mmHg?

Answer 1

Step 1

Gay-Lussca's Law is used here.

It states that the pressure of a given mass of gas varies directly with the absolute temperature when the volume is kept constant.

------------

Step 2

Mathematically:

P1/T1 = P2/T2 (1)

Data provided:

Conditions 1 => P1 = pressure 1 = 750.0 mmHg; T1 = absolute temperature = 323.0 K

Conditions 2 => P2 = unknown; T2 = 273 K

-----------

Step 3

P2 is cleared from (1):

P1/T1 x T2 = P2

(750.0 mmHg/323.0 K) x 273 K = 634.0 mmHg

Answer: P2 = 634.0 mmHg