ConceptConceptDocsDocuments

CAIE A-Level Chemistry 8.3.1 Catalysts and Catalysis

Practise defining a catalyst and representing its lower-activation-energy mechanism on energy and distribution diagrams.

Syllabus
2028–2030
Course
Chemistry 9701
Level
AS

Exam points

  • define a catalyst as increasing reaction rate without being chemically changed overall by the reaction
  • draw an alternative reaction pathway with a lower maximum while leaving ΔH unchanged
  • move the EA threshold left on a Boltzmann plot and link the larger area beyond it to faster reaction

8.3.1—And use the terms catalyst and catalysis question 1

[Maximum number: 2]

Hydrogen halides are compounds formed when halogens (Group 17 elements) react with hydrogen. The bond polarity of the hydrogen halides decreases from HF to HI.

Some relevant data are shown in the table.

Table for Question 8.3.1—And use the terms catalyst and catalysis question 1 — CAIE A-Level Chemistry AS

Hydrogen chloride undergoes a reversible reaction with oxygen.

4HCl( g)+O2( g)⇌2Cl2( g)+2H2O( g)4 \mathrm{HCl}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \rightleftharpoons 2 \mathrm{Cl}_{2}(\mathrm{~g})+2 \mathrm{H}_{2} \mathrm{O}(\mathrm{~g})

The reaction is carried out at 400∘C400^{\circ} \mathrm{C} in the presence of a copper(II) chloride catalyst.

State the type of catalyst used in this reaction. Explain how a catalyst is able to increase the rate of a chemical reaction.

All question bank results loaded