Question

Click the DeltaH is an Extensive Property button within the activity, and analyze the relationship between the two reactions that are displayed. The reaction that was on the screen when you started and its derivative demonstrate that the change in enthalpy for a reaction, ΔH, is an extensive property. Using this property, calculate the change in enthalpy for Reaction 2.

Answer 1

Consider the reaction
2Al(OH)3(s)→Al2O3(s)+3H2O(l)
with enthalpy of reaction
ΔHrxn∘=21.0kJ/mol
What is the enthalpy of formation of Al2O3(s)?

Substance ΔHf∘ (kJ/mol)
HCl(g) −92.0
Al(OH)3(s) −1277.0
H2O(l) −285.8
AlCl3(s) −705.6
H2O(g) −241.8