How to find the new pressure?

Question

A gas has an initial volume of 0.9 L, an initial pressure of 32 atm and a temperature of 24.80 K. The temperature is decreased to 10.01 K. At this new temperature the volume is 744 mL. What is the new pressure?

Answer 1

I assume this is an ideal gas. Since the amount of gas is constant, you can use the relation

P₁V₁ / T₁ = P₂V₂ / T₂

P₁ = 32 atm

V₁ = 0.9 L

T₁ = 24.80 K

P₂ = ?

V₂ = 0.744 L

T₂ = 10.01 K

Solve for P₂.

P₂ = (T₂ / V₂) (P₁V₁ / T₁)

Plug in the numbers and get P₂ in atm.