Enthalpy: H. The heat content that is stored in a chemical system. • Enthalpy Change: ∆ = − . • Conservation of Energy: Energy cannot be created or destroyed. Heat transferred between system and surroundings. • (Chemical) System: The chemical compounds being studied-...
Thermometer: It is part of surroundings so can measure temp change in surroundings. • Kelvin Scale: Scale starts at absolute zero 0 K or -273oC. 1 K rise = 1 oC rise. oC + 273 = K. • Calculating Energy Change: Energy change of surroundings is calculated using q =...
Average Bond Enthalpy: Enthalpy change when one mole of atoms of gaseous covalent bonds is broken. Use average bond enthalpies to calculate enthalpy changes of reaction ∆rH without experiments. To use must have energy required to break bond = endothermic = positive...
Experiments: The experiments in previous section allow enthalpy changes to be determined directly. Hess’ Law determines it indirectly. • Difficult to determine standard enthalpy change of combustion directly as… - Carbon dioxide and water would also be formed. -...