Four liters of gas at standard pressure is compressed into 0.85 l gas cylinder. what is the new pressure

              4.70 atm

Solution:
               According to Boyle's Law, " The Volume of a given mass of gas at constant temperature is inversely proportinal to the applied Pressure". Mathmatically the initial and final states of gas are given as,

                                      P₁ V₁  =  P₂ V₂    (1)

Data Given;
                   P₁  =  1 atm (standard pressure)

                   V₁  =  4 L

                   P₂  =  ??

                   V₂  =  0.85 L

Solving equation 1 for P₂,

                    P₂  =  P₁ V₁ / V₂

Putting values,

                    P₂  =  (1 atm × 4 L) ÷ 0.85 L

                    P₂  =  4.70 atm

Result:
           As the volume has decreased from 4 L to 0.85 L, therefore, pressure got increased from 1 atm to 4.70 atm.