combined gas law

Question

helium balloon released into air at 20C Initial volume is 5.00L and pressure is 760mmHg Balloon ascends to altitude of 20km where pressure is 76.0 mmHg and temp is -50C What is new volume in Liters

Answer 1

The combined gas law combines relationships between volume and temperature, volume and pressure, and temperature and pressure into one equation. The equation can be used whenever the number of gas molecules remains the same, like in your problem. The equation is:

 

(P₁V₁)/T₁ = (P₂V₂)/T₂,

 

where P₁, V₁, and T₁ are the gas's initial pressure, volume, and temperature and P₂, V₂, and T₂ are the gas's final pressure, volume, and temperature after one or more has been changed.

 

For this problem, you're given initial values P₁ = 760, V₁ = 5, and T₁ = 20, as well as final values P₂ = 76 and T₂ = -50. Plug these values into the equation and solve for the final volume V₂.