Thermochemisrty

Exothermic

Give out heat

Endothermic

Take in heat

Heat of Reaction

The heat change that takes place when a chemical reaction proceeds according to its balanced equation.

Heat of Combustion

The heat change that takes place when 1 mole of a substance is completely burned in excess O2.

Heat of Combustion is measured by…….

Bomb calorimeter

Kilogram Calorific Value

This is the heat energy produced when 1kg of a fuel is burned in O2. (We use this number to compare the efficiency of fuels)

Bond Energies

Is the difference between the energy required to break all old bonds and the energy required to make all new bonds.

What happens Bond Energies?

Energy is needed to break bonds (reactants). Energy is released when bonds are made (products).

Heat of Neutralisation

The heat change that takes place when 1 mole of H+ ions and 1 mole of OH- ions react together

E = mcθ is used to calculate the ΔH. What do they stand for.

E=energy, m=mass of water in kg, c=4200J/kg/K, θ=temperature rise

C = 4200J/kg/K is called the specific heat capacity of water

It is the energy required to raise 1kg of water through 1°K

Heat of Formation

It is the heat change that takes place when 1 mole of a substance is formed from its elements.

Hess’s Law

The heat change for a given reaction was dependant only on the initial and final states of the system and was independent of the pathway followed