A known volume of ideal gas is contained in a cylinder fitted with a piston and held at constant pressure. If the temperature changes from 25oC to 100 oC, by what factor does the volume change?

Question

A. does the volume decrease or increase ?

B. By a factor of ?

Answer 1

At constant pressure, we are dealing with Charles' Law.

A). An increase in temperature should cause an increase in volume

B). V1/T1 = V2/T2 Charles Law

V1 = initial volume

T1 = initial temperature = 25ºC + 273 = 298K (note: temperature must be in Kelvin)

V2 = final volume

T2 = final temperature = 100ºC + 273 = 373K

We can solve for V2 in terms of V1

V2 = V1T2 / T1

V2 = V1(373/298)

V2 = 1.25V1

So the volume will increase by a factor of 1.25