what would the final pressure of 40L of gas at 90 pa be if the volume was increased to 120L

Answer 1

The question does not say about temperature

If we assume temperature be constant

Then

P1 V1 = P2 V2

Given P1 = 90 Pa,, V1 = 40 L

V2 = 120 L, P2 =?

90*40 = P2 * 120

P2 = 90*40 /120 = 30 Pa

This process has to be isothermal compression