Educator

Energy in Chemical Reactions

• The forms of energy are kinetic – from motion – and potential – from position or chemical composition

• Learn units of energy: SI – Joule; the Calorie in nutrition; Cal = 1000cal = 4.18kJ

• Energy is conserved in changes: not created or destroyed – First Law of Thermodynamics.

• Master definition of heat capacity, and how to measure it.

• Enthalpy is heat energy change at constant pressure

• The calorimeter useful for determining enthalpy changes of chemical and physical changes, including changes of phase

• Exothermic means heat energy leaves the system to surroundings (feels hot)

• Endothermic means heat energy enters the system from surroundings (feels cold)

• Hess’s Law – a First Law statement – treat enthalpy changes by algebra

• Learn definition of Standard Enthalpy of Formation, DH⁰

• Do examples on using Standard Enthalpies of Formation to calculate enthalpy changes in reactions etc.