# Calculate ΔH for the following reaction:8 Al(s) + 3 Fe3O4(s) --> 4 Al2O3(s) + 9 Fe(s)

SAGAR SINGH - IIT DELHI
878 Points
13 years ago

Dear sachin,

ΔH for a reaction is equal to the sum of the heats of formation of the product compounds minus the sum of the heats of formation of the reactant compounds:

ΔH = Σ ΔHf products - Σ ΔHf reactants

Omitting terms for the elements, the equation becomes:

ΔH = 4 ΔHf Al2O3(s) - 3 ΔHf Fe3O4(s)

The values for ΔHf may be found in the Heats of Formation of Compounds table. Plugging in these numbers:

ΔH = 4(-1669.8 kJ) - 3(-1120.9 kJ)

ΔH = -3316.5 kJ

All the best.

Win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.

Sagar Singh

B.Tech, IIT Delhi

pratik nayak
33 Points
13 years ago

ΔH for a reaction is the sum of the heats of formation of the product compounds - the sum of the heats of formation of the reactant compounds:

ΔH = Σ ΔHf products - Σ ΔHf reactants

ΔH = 4 ΔHf Al2O3(s) - 3 ΔHf Fe3O4(s)

The values for ΔHf are present in the Heats of Formation of Compounds table.

ΔH = 4(-1669.8 kJ) - 3(-1120.9 kJ)

ΔH = -3316.5 kJ