Question

A balloon filled with 1.26 g of nitrogen gas has a volume of 1.12 L. Calculate the volume of the balloon after 1.26 g of helium gas is added while T and P remain constant.

Answer 1

Solution:- If T and P are constant then Volume is gas is directly proportional to the moles of the gas. Since moles are directly proportional to the grams of the gas, the volume would be directly proportional to the grams of the gas.

For N₂, 1.26 g x (1mol/28g) = 0.0450 mol N₂

for He, 1.26 g x (1mol/4.0g) = 0.315 mol He

Total moles of the gas = 0.0450 + 0.315 = 0.360

Initial moles of the gas are 0.0450 and initial volume is 1.12 L. Final moles are 0.360, what would be the final volume?

Since volume is directly proportional to the moles of the gas....

V₁/V₂ = n₁/n₂

rearranging this for V₂, V₂ = V₁.n₂/n₁

V₂ = 1.12 L x 0.360 mol/0.0450 mol

V₂ = 8.96 L

So, after adding 1.26 g of Helium gas to the balloon that already has 1.26 g of N₂, the volume would be 8.96 L.