9.4 - Hess's Law & Enthalpy Cycles

Question 1

Define Hess’s Law

Answer 1

If a reaction can take place via 2 routes, and the starting and finishing conditions are the same, the total enthalpy change is the same for each route.

Question 2

If enthalpy change of combustion is,
reactants > products,
denoted by A, what is the formula for the indirect route?

Answer 2

A = B-C

Question 3

If enthalpy change of formation is,
reactants > products,
denoted by A, what is the formula for the indirect route?

Answer 3

A = C-B