4. A constant amount of ideal gas is held in a syringe, one end of which is sealed. The gas is then compressed by pushing the other end of the syringe slowly inwards so that the volume occupied by the gas is halved. a Before compression, the pressure inside the syringe was 1.0 x 105 Pa. Calculate the pressure inside the syringe after the gas was compressed. [2] b Outline why it is necessary to compress the ideal gas slowly. [1] c If the gas were compressed quickly, suggest and explain how the pressure inside the syringe would compare with the value you calculated in part a. [2]