Question

When 1 mole of a fuel burns at constant pressure, it produces 3452 kJ of heat and does 11 kJ of work. What are E and H for the combustion?

a) E = 3463 kJ, H = 3452 kJ
b) E = 3463 kJ, H = 3463 kJ
c) E = 11 kJ, H = 3452 kJ
d) E = 11 kJ, H = 11 kJ

Answer 1

The correct values for the internal energy change (E) and the enthalpy change (H) for the combustion are E = 3441 kJ and H = 3452 kJ, since E is calculated by subtracting the work done by the system from the heat produced.

Step-by-step explanation:

When 1 mole of a fuel burns at constant pressure, it produces 3452 kJ of heat and does 11 kJ of work. To find the values of E (internal energy change) and H (enthalpy change) for the combustion, we can use the relationships between these quantities, heat, and work done.

The enthalpy change (H) at constant pressure is equal to the heat produced, so H = 3452 kJ. The internal energy change (E) is the sum of the heat produced and the work done on or by the system. Since work is done by the system in this case (expansion work), it is negative with respect to the system, and we have E = Heat + Work = 3452 kJ - 11 kJ = 3441 kJ.

Therefore, the correct answer is:
a) E = 3441 kJ, H = 3452 kJ.