Use Hess's Law to calculate the enthalpy change for the reaction
WO₃(s) + 3H₂(g) $\to$ W(s) + 3H₂O(g)
From the following data:
2W(s) + 3O₂(g) $\to$ 2WO₃(s) $\Delta$ H = -1685.4 kJ
2H₂(g) + O₂(g) $\to$ 2H₂O(g) $\Delta$ H = -477.84 kJ

Question

Use Hess's Law to calculate the enthalpy change for the reaction
WO₃(s) + 3H₂(g)

\to

W(s) + 3H₂O(g)
From the following data:
2W(s) + 3O₂(g)

\to

2WO₃(s)

\Delta

H = -1685.4 kJ
2H₂(g) + O₂(g)

\to

2H₂O(g)

\Delta

H = -477.84 kJ

Quizplus · Accepted Answer

The correct answer is A because the enthalpy change for the reaction can be calculated using Hess's Law:ΔH = ΔH1 + ΔH2ΔH = (-1685.4 kJ) + (-477.84 kJ)ΔH = -2163.24 kJThe enthalpy change for the reaction is -2163.24 kJ.

Use Hess's Law to Calculate the Enthalpy Change for the Reaction