Freaking out about this

Question

A 1.1 L tank of N₂ gas has a pressure of 1.25 atm. What is the pressure (in mmHg) if the volume is increased to 3.6 L? Assume the temperature remains constant. 

Round your answer to the nearest tenth.

Answer 1

The Ideal Gas Law is PV = nRT or PV/T = nR

In a closed system, where the number of moles stays the same (no gas leaks in or out) then between time 1 and time 2 we can say:

P₁V₁/T₁ = nR = P₂V₂/T₂

or P₁V₁/T₁ = P₂V₂/T₂

If temperature remains constant (doesn't change) then P₁V₁ = P₂V₂ or P₂ = P₁V₁/V₂

V₁ = 1.1 L

V₂ = 3.6 L

P₁ = 1.25 atm

So plug those numbers into the equation:

P₂ = P₁V₁/V₂

P₂ = (1.25)(1.1)/(3.6) with the answer in units of "atm"