Physical Chemistry #15: Enthalpy Change and Enthalpy Profile Diagrams (Slides and Student Led Tasks)

In this lesson we discuss enthalpy changes, exothermic and endothermic reactions and enthalpy profile diagrams. This is lesson fifteen in our physical chemistry series for Unit 5: Chemical Energetics (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum).

LESSON OBJECTIVE: Understand the properties of exothermic and endothermic reactions and to describe the enthalpy change of various reactions under standard conditions.

LEARNING OUTCOMES (from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum)
5.1 Enthalpy change, ΔH
a) explain that chemical reactions are accompanied by energy changes, principally in the form of heat energy; the energy changes can be exothermic (ΔH is negative) or endothermic (ΔH is positive)

b) explain and use the terms:
i) enthalpy change of reaction and standard conditions, with particular reference to: formation, combustion, hydration, solution, neutralisation, atomisation
ii) bond energy (ΔH positive, i.e. bond breaking)