Question

Calculate the standard enthalpy change for the reaction

2A+B⇌2C+2D

where the heats of formation are given in the following table:

Substance	ΔH∘f (kJ/mol)
A	-275
B	-413
C	223
D	-521

Express your answer in kilojoules.

- Part A Calculate the standard enthalpy change for the reaction 2A+B=2C+2D where the heats of formation are given in the following table: Substance A AH (kJ/mol) -275 -413 223 -521 B D Express your answer in kilojoules. View Available Hint(s) O AED * * O 2 ? AH Submit

Answer 1

Given:
Hof(A) = -275.0 KJ/mol
Hof(B) = -413.0 KJ/mol
Hof(C) = 223.0 KJ/mol
Hof(D) = -521.0 KJ/mol

Balanced chemical equation is:
2 A + B ---> 2 C + 2 D

ΔHo rxn = 2*Hof(C) + 2*Hof(D) - 2*Hof( A) - 1*Hof(B)
ΔHo rxn = 2*(223.0) + 2*(-521.0) - 2*(-275.0) - 1*(-413.0)
ΔHo rxn = 367 KJ
Answer: 367 KJ