Energetics

Question 1

Standard Enthalpy Change of Formation

Answer 1

the enthalpy change when 1 mole of the compound is formed from its elements under standard conditions (298K and 100kpa), all reactants and products being in their standard states.

Question 2

Standard Enthalpy Change of Combustion

Answer 2

the enthalpy change when one mole of a substance is combusted completely in oxygen under standard conditions. (298K and 100kPa), all reactants and products being in their standard states.

Question 3

Hess’s Law

Answer 3

states that total enthalpy change for a reaction is independent of the route by which the chemical change takes place

Question 4

mean bond energy

Answer 4

the enthalpy needed to break the covalent bond into gaseous atoms, averaged over different molecules.