Answer to Question #25887 in Organic Chemistry for Florayne

Question

A balloon is filled with hydrogen at 26oC. The balloon expands until the pressure is equal to the barometric pressure of 750 Torr. The balloon rises to an altitude of 6000 ft, where the pressure is 600 Torr and the temperature is 14oC. What is the change in the volume of the balloon as it ascends to 6000 ft ?

Answer 1

This question can be solved by using the ideal gas law:

PV = nRT

But even if you have two different conditions the amount is the same (R is const), so:

P₁V₁ = nRT₁
n = P₁V₁/RT₁
n = P₂V₂/RT₂
P₁V₁/RT₁ = P₂V₂/RT₂
P₁V₁/T₁ = P₂V₂/T₂

If starting volume is V₁:

T₁ = 26 C
T₂ = 14 C

P₁ = 750 Torr
P₂ = 600 Torr

750 Torr V₁/26 C = 600 Torr V₂/14 C
28.85 V₁ = 42.86 V₂

0,67*V₁ = V₂