3.2 Key Terms

2. Change of Formation, the energy change that takes place when 1 mole of a compound is formed from its constituent elements in their standard state, under standard conditions
5. Change of Reaction, the energy change associated with a given reaction
7. Equilibrium, exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction
8. Distribution, the distribution of energies of molecules at a particular temperature, often shown as a graph
9. Bond Enthalpy, the mean energy needed for 1 mole of a given type of gaseous bonds to undergo homolytic fission
11. Chateliers Principle, when a system in dynamic equilibrium is subjected to a change, the position of equilibrium will shift to minimise the change
13. a diagram of a reaction that allows you to compare the enthalpy of the reactants with the products
16. Change of Neutralisation, the energy change associated with the formation of 1 mole of water from a neutralisation reaction, under standard conditions
17. the energy change that takes place when 1 mole of a substance is completely combusted, under standard conditions
18. a catalyst used in a reaction which is in the same phase as the reactant

1. of Reaction, the change in concentration of a reactant or product in a given time
2. a reaction in which the enthalpy of the products is smaller than the enthalpy of the reactants (9)
3. Energy, the minimum energy required to start a reaction by breaking bonds in the reactants
4. a reaction in which the enthalpy of the products is greater than the enthalpy of the reactants (10)
6. Law, states that the enthalpy change in a chemical reaction is independent of the route it takes
10. a catalyst used in a reaction which is in a different phase to the reactants
12. the quantitative study of energy change in a chemical reaction
14. Heat Capacity, the energy required to raise 1g of a substance by 1K
15. Constant, gives the position of where equilibrium lays, by giving the ratio between products and reactants