Chemical Thermodynamics

2. Water initially at 155°C is contained in a piston- cylinder assembly. The water undergoes a process to the corresponding saturated vapor state, during which the piston moves freely in the cylinder. There is no heat transfer with the surroundings. If the change of state is brought about by the action of a paddle wheel, determine the net work per unit mass in kJ/kg and the amount of entropy produced per unit mass in kJ/kg. [MO2]

Question 1 (40 marks) Determine Z and V for steam at 250 °C and 1800 kPa by the following a) The ideal gas equation. b) The generalized compressibility-factor correlation. c) d) The Pitzer method with tabulated Z & Z¹ from Lee-Kesler correlation Appendix D. The truncated virial equation with the following experimental values of virial coefficients: B = -152.5 cm³ mol¹; C = -5800 cm mol-². e) f) The truncated virial equation, with a value of B from the generalized Pitzer correlation. The steam tables.

Question 3 (20 marks) A Carnot cycle heat engine operating between 630 °C and 25 °C absorbs 1200 kJ of heat from the high-temperature reservoir. The work produced is used to power another Carnot cycle heat pump which transfers 1500 kJ of heat from 630 °C to a reservoir at a higher temperature TH. a) Calculate the amount of work exchanged between the two cycles. Calculate the temperature TH b) c) Calculate the amount of heat that is transferred to the reservoir at Ti

Question 3 (20 marks) A Carnot cycle heat engine operating between 630 °C and 25 °C absorbs 1200 kJ of heat from the high-temperature reservoir. The work produced is used to power another Carnot cycle heat pump which transfers 1500 kJ of heat from 630 °C to a reservoir at a higher temperature TH. a) Calculate the amount of work exchanged between the two cycles. Calculate the temperature TH b) c) Calculate the amount of heat that is transferred to the reservoir at Ti

For an ideal gas mixture that is 40% A and 60% B, what is the partial molar enthalpy of component A? For an ideal gas mixture that is 40% A and 60% B, what is the partial molar enthalpy of component B?

Chemical thermodynamics in the manufacture of methanol Methanol (CH3OH) is used to manufacture a large number of important chemicals, such as formaldehyde (HCHO) which is employed in the manufacture of a variety of polymers; methyl-tertiary-butylether ((CH3)3OCH3), which has been used as a lead-free anti-knocking agent in petrol; acetic acid (CH3CO₂H), etc. Annual production of methanol has been increasing: from 3.3 MTe/yr in 1982¹ to 20 MTe/yr in 1991.² Methanol is manufactured using synthesis gas (a mixture of carbon monoxide, CO, and hydrogen, H₂) through the following chemical equilibrium. (a) Use the data in Table 1 to calculate the following. (i)The enthalpy change for the reaction, under standard conditions. Comment on your answer. (ii) The standard entropy change for the reaction. Comment on your answer. (iii) The standard Gibbs energy change for the reaction, under standard conditions. Comment on your answer. (iv) The equilibrium constant for the reaction equilibrium, under standard conditions. Comment on your answer. (v) The change in the heat capacity at constant pressure for the chemical reactions, under standard conditions.

2. Consider a pan of water being heated. Which method is a more efficient way of heating water? Explain. [MO1] a. By placing it on an electric range. b. By placing a heating element in the water.

8. Air dissolves in a liquid solvent so that the O₂ concentration in the solvent is three times that of the N₂ concentration. Compare the fugacities of O2 and N₂ dissolved in the solvent in the presence of air and explain the reason for your answer.

5. Water at 140°C and 10.0 bar expands through a throttle to 1.0 bar. What is the outlet temperature and how many phase(s) are in the effluent? Explain your answer.

1. Water, initially a saturated liquid at 160°C, is contained in a pistol-cylinder assembly. The water undergoes a process to the corresponding saturated vapor state, during which the piston moves freely in the cylinder. If the change of state is brought about by heating the water as it undergoes an internally reversible process at constant pressure and temperature, determine the work and heat transfer per unit mass in kJ/kg. [MO1]