Question

A gas is compressed to 75cm3 to a volume of 30cm3. Its temperature remains the same The pressure of the gas after it has been compressed is 110 Pa. What was the pressure before it was compressed?

Answer 1

Given parameters:

Initial volume  = 75cm³

New volume  = 30cm³

New pressure  = 110Pa

Unknown:

Initial pressure = ?

Solution:

Condition: temperature is constant

We simply apply Boyle's law to this problem:

   " the volume of a fixed mass(mole) of a 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 values

          1 and 2 are the initial and final states.

Input the parameters and solve for P₁;

     P₁ x 75  = 110 x 30

   P₁ = 44Pa

         

The initial pressure is 44Pa