B The Assignment Brief Assignment Brief This assignment is to be completed independently. You will need a periodic table and a calculator. LO1 Understand enthalpy changes associated with exothermic and endothermic reactions AC 1.1 Interpret enthalpy profile diagrams for exothermic and endothermic reactions including the concept of activation energy, EA AC 1.2 Define standard conditions and standard enthalpy changes of combustion, formation and reaction. AC 1.3 Calculate enthalpy changes of reaction from average bond enthalpy values or experimental data AC 1.4 State Hess' Law and use enthalpy cycles to indirectly determine enthalpy changes 1. a) Describe the difference between exothermic and endothermic reactions. b) Define activation energy. c) Draw a labelled enthalpy profile diagram for an endothermic reaction.