Equation of state of a perfect gas, work done on compressing a gas
- An oxygen cylinder of volume 30 litre has 18.20 moles of oxygen. After some oxygen is withdrawn from the cylinder, its gauge pressure drops to 11 atmospheric pressure at temperature 27^°C. The mass of the oxygen withdrawn from the cylinder is nearly… Answer: 3. 0.116 kg Key idea: use PV=nRT for the gas left, then subtract from the initial moles. The gauge pressure must be converted to abs... 1
- A container has two chambers of volumes V_1 = 2 litres and V_2 = 3 litres separated by a partition made of a thermal insulator. The chambers contains n_1 = 5 and n_2 = 4 moles of ideal gas at pressures p_1 = 1 atm and p_2 = 2 atm, respectively. When… Answer: 2. 1.6 atm Key idea: no heat or work leaves the container, so the total internal energy is conserved. For the same gas, this gives n... 1
- The following graph represents the T-V curves of an ideal gas (where T is the temperature and V the volume) at three pressures P_1, P_2 and P_3 compared with those of Charles's law represented as dotted lines.Then the correct relation is: Answer: 1. P₁>P₂>P₃ Key idea: For an ideal gas PV=nRT , so at fixed pressure T=P/nRV : the T-V line has slope P/nR . A larger pressure gives... 1
- A cylinder contains hydrogen gas at pressure of 249 kPa and temperature 27^°C.Its density is : (R = 8.3 J mol^-1 K^-1) Answer: 2. 0.2 kg/m ³ Use the ideal gas equation in density form: P=ρ RT/M . M=2×10⁻³ kg/mol, T=300 K, P=2.49×10⁵ Pa. ρ=PM/RT=frac2.49×10⁵×2... 1