1# Chemical energy
2Chemical energy = heat content = enthalpy
4$$\Delta H = H_{\text{products}} - H_{\text{reactants}}$$
6**Exothermic** - energy released from system
8**Endothermic** - energy absorbed by system
9Must specify states (latent heat)
11## Thermochemical equations
13$\Delta H$ notates energy change (i.e. kJ / mol)
15Exothermic - negative $\Delta H$
16## Calorimetry
18$$E = mc \Delta T$$
20$$\text{calibration factor} = {E \over \Delta T} = {VIt \over \Delta T} \quad \text{J/K}$$
22## Fuels
24Substance used for energy production by **combustion** (exothermic)
26Fossil fuels - decaying organic material (e.g. coal, petrol, nat. gas)
27### Efficiency
29$$\text{% efficiency} = {\text{energy obtained in desired form} \over \text{energy available before conversion}} \times 100$$