Use the H° and H° information provided to calculate H° for IF: IF₇(g) + I₂(g) → IF₅(g) + 2IF(g) Δ_r H°= -89 kJ H°(kJ )
IF₇(g) -941
IF₅(g) -840

Question

Use the H° and H° information provided to calculate H° for IF: IF₇(g) + I₂(g) → IF₅(g) + 2IF(g) Δ_r H°= -89 kJ H°(kJ ) IF₇(g) -941 IF₅(g) -840

Quizplus · Accepted Answer

We can use Hess's Law and manipulate the given reactions to get the desired reaction and its enthalpy change. First, we reverse the second given reaction: IF(g) → I₂(g) + I₂(g) ΔH = -342.9 kJ mol^-1 Next, we add the first and reversed second reactions to get the desired reaction: IF₇(g) + IF(g) → IF₅(g) + 2I₂(g) ΔH = -95 kJ mol^-1 However, we need to adjust the enthalpy change according to the stoichiometry of the balanced equation. The equation involves one mole of IF₇ and one mole of IF, so we need to divide the enthalpy change by one: ΔH per mole of IF₇ = -95 kJ mol^-1 / 1 mol = -95 kJ mol^-1 Therefore, the answer is D) -95 kJ mol^-1.

Use the H° and H° Information Provided to Calculate