Gas in a balloon occupies 3.3 L. What volume will it occupy if the pressure is changed from 100.0 kPa to 90.0 kPa (at constant temperature).

• Ishankahps: Since the temperature is a constant, we can use Boyle's law to solve this.
  
  Boyle' law says "at a constant temperature, the pressure of a fixed amount of an ideal gas is inversely proportional to its volume.
  
  P α 1/V               ⇒                 PV = k (constant)
  
  Where, P is the pressure of the gas and V is the volume.
  
  Here, we assume that the gas in the balloon is an ideal gas. 
  
  We can use Boyle's law for these two situations as,
              P₁V₁ = P₂V₂
  
  P₁ = 100.0 kPa = 1 x 10⁵ Pa
  V₁ = 3.3 L
  P₂ = 90.0 x 10³ Pa
  V₂ =?
  
  By substitution,
      1 x 10⁵ Pa x 3.3 L = 90 x 10³ Pa x V₂
                              V₂ = 3.7 L
  Hence, the volume of gas when pressure is 90.0 kPa is 3.7 L.