500 mL of He at 98 kPa expands to 750 mL. Find P2.

0.65atm or 65.3kPa

Explanation:

Given parameters:

Initial volume of He = 500mL

Initial pressure = 98kPa, this gives 0.967atm

Final volume = 750mL

Unknown:

Final pressure = ?

Solution:

A good grasp of Boyle's law should suffice here. The law states that:

"the volume of a fixed mass of gas varies inversely as the pressure changes if the temperature is constant".

Mathematically;

P₁ V₁ = P₂ V₂

where P and V are pressure and volume

1 and 2 are the initial and final states;

Now, solve for the unknown P₂;

0.967 x 500 = P₂ x 750

P₂ = 0.65atm or 65.3kPa