5.2 Hess's law

Question 1

What is Hess’s law?

Answer 1

The enthalpy change for a reaction depends only on the enthalpy of the products and the enthalpy of the reactants. It is independent of the reaction pathway

Question 2

What is the standard enthalpy change?

Answer 2

The standard enthalpy change of reaction is the enthalpy change when 1 mole of a compound is formed from its elements in their standard states at 298 K and 100 kPa

Question 3

What is the standard enthalpy change of combustion?

Answer 3

The standard enthalpy change when 1 mole of a compound undergoes complete combustion in excess oxygen under standard condition