Question 1. (a) Convert the following units:

(i) 300 K = °C
(ii) 25°C = K
(iii) 1 bar gauge = bar absolute
(iv) 1 kN m^-2 = bar
(v) 2 bar = N m^-2 (take atmospheric pressure = 1 bar)

(b) What are the units of the following?

(i) specific internal energy
(ii) specific volume
(iii) work.

Question 2. A gas at a pressure of 2 bar occupies a volume of 0.2 m³. If the temperature of the gas is 25°C and the characteristic constant for the gas is 0.35 kJ kg^-1 K^-1, calculate :
(a) the mass of the gas

(b) the pressure of the gas after it is compressed isothermally to half of its original volume.

Question 3. 0.5 kg of a gas is held in a rigid container of volume 0.25 m³ at a temperature of 20°C. 20 kJ of heat energy is required to increase the temperature of the gas to 60°C.

When the same mass of gas is heated at constant pressure, 30 kJ of heat energy is required to create the same temperature rise. Calculate:

(i) the specific heat capacities of the gas at constant volume and constant pressure
(ii) the initial pressure of the gas

(iii) the change in volume of the gas when it was heated at constant pressure.

Question 4. In a closed system a gas is compressed from a pressure of 3 bar absolute to a pressure of 5 bar absolute, and its volume changes from 0.9 m³ to 0.6 m³ according to the law p₁V₁ⁿ = p₂V₂ⁿ Calculate:

(a) the value of the index n

(b) the work done, stating whether it is done on the system or on the surroundings.