ConceptConceptDocsDocuments

Edexcel IAL Chemistry 9.5 Catalysts and alternative pathways

State both the alternative route and lower Eₐ, then use rate evidence to identify a catalyst while keeping reactant/product energy levels and K unchanged.

Syllabus
First assessment 2019
Course
Chemistry YCH11
Level
AS

Exam points

  • State that a catalyst supplies an alternative pathway with lower activation energy.
  • Use reaction-time evidence to identify which added substance acts as a catalyst.
  • Explain that a catalyst changes Eₐ but not ΔH, equilibrium position or equilibrium constant.

9.5—The role of catalysts in providing alternative reaction routes of lower activation energy question 1

[Maximum number: 1]

The Sabatier process uses carbon dioxide and hydrogen to produce methane and water.

CO2( g)+4H2( g)⇌CH4( g)+2H2O( g)ΔrH=−165 kJ mol−1\mathrm{CO}_{2}(\mathrm{~g})+4 \mathrm{H}_{2}(\mathrm{~g}) \rightleftharpoons \mathrm{CH}_{4}(\mathrm{~g})+2 \mathrm{H}_{2} \mathrm{O}(\mathrm{~g}) \quad \Delta_{\mathrm{r}} H=-165 \mathrm{~kJ} \mathrm{~mol}^{-1}

The process is carried out at a temperature of 400∘C400^{\circ} \mathrm{C} and a pressure of 30 atm , in the presence of a nickel catalyst.

State how a catalyst increases the rate of a reaction.

All question bank results loaded