8.89 L of hydrogen gas is collected at 38.8 °C. Find the volume the gas will occupy at - 39.9 °C if the pressure remains constant.

Charle's Law states: V/T = k

where k is a constant

We can get this from the ideal gas law when pressure, and number of moles are held constant.

We can also use this and say

V₁/T₁ = k = V₂/K₂

V₁/T₁ = V₂/K₂

38.8°C = 311.95 K

-39.9°C = 233.25 K

8.89L/311.95K = V₂/233.25K

V₂ = 6.65 L

The gas will have a volume of 6.65 L at - 39.9°C.