IB Chemistry HL 1.1.3 Stability and Energy Questions

Apply profile-based reasoning to connect ΔH, relative stability, reaction progress and activation-energy barriers in catalysed and uncatalysed paths.

Exam points

Draw and label an energy or enthalpy profile with reaction progress, reactants, products and the sign or magnitude of ΔH.
Interpret relative reactant and product energy levels to deduce endothermic or exothermic change and which side is more energetically stable.
Label or compare activation energy and the energy barrier on a potential-energy profile, including profiles with and without a catalyst where shown.

Learn this topic

Study 1.1.3—Stability and energy conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

[Maximum number: 3]

Phenylethene (styrene) is produced from ethylbenzene in a gas-phase equilibrium.

Figure for Question IB Chemistry HL 1.1.3 Stability and Energy Questions question 1 — IB Chemistry HL

The forward reaction is endothermic, uses iron(III) oxide as a catalyst, and takes place at 900 K .

Sketch the energy profile for the reaction, both with and without the catalyst, labelling $\Delta H$ and the activation energies.

All question bank results loaded

Learn this topic

IB Chemistry HL 1.1.3 Stability and Energy Questions question 1