1. Consider chemical reaction as shown below:

() + 2 () (g) . . = 890 J

1. Give the meaning of the standard heat reaction value given above in terms of the amount of energy associated with the molecular bonding of component A, B, and C.

1. 2. marks)
2. For the above reaction, explain how the temperature of the reactor can be maintained.

2. 2. marks)
3. If the kinetic and potential energy changes are too small and there is no work interaction involve during the process, express heat, Q, in terms of N, where N is the number of moles of B that has been consumed.

(4 marks)

2. Ethylene (C₂H₄) may be formed from ethane (C₂H₆) by dehydrogenation process according to the reaction:

C₂H₆ (g) C₂H₄ (g) + H₂ (g)

In a commercial reactor system, the ethane is supplied as a liquid at 25C to a heater where it is heated and vapourised leaving as a vapour at 400C. The vapour then passes the catalytic reactor in which a conversion of 50% is achieved. It may be assumed that there are no other reactions, that operation is at a pressure of one atmosphere and that the stream leaving the reactor is all in the vapour state. With a complete block diagram of the process, determine the heat transfer rate (kW) required to the reactor if it is operated isothermally. Evaluate on the value of the heat transfer rate obtained from your calculation.

Given data:

Standard heat of formation and heat capacity

Component	State	(kJ/mol)	Cp (kJ/molK)
Ethylene	liquid	---	---
	gas	52.28	0.41
Ethane	liquid	---	---
	gas	84.67	0.49
Hydrogen	gas	---	0.059

The C_p values may be assumed independent of temperature.

(14 marks)