A piston contains air at temperature 430K and pressure 14Pa. The air is heated to 1200K while being kept at a constant volume of 5 litres. Assume the gas constant for air is 287 Jkg-1K-1. Calculate the pressure and the mass of the air following heating. Question 2 A cylinder of air occupies a volume of 30 litres. The temperature of the gas is 100k and the pressure is 20 Pa Assume the gas constant of air is 287 Jkg-1K-1. Calculate the mass of the air. Question 4 A cylinder contains a gas at temperature 514K, volume 30m and a pressure 14 Pa. The polytropic process index value (n) of the gas in its initial state is 1.1. Assume the gas constant for the gas is 188 Jkg-1K-1. Calculate the initial mass of the gas. The gas is then cooled to a temperature of 430K. At this temperature the pressure is 30Pa. Find the polytropic process index value (n) for the gas after it has been cooled.