Catalysts

Part of the Energy, Rates and Equilibrium section of Coddy's Chemistry journey. Lesson 19 of 35.

A catalyst speeds a reaction up and comes out unchanged.

It offers a route with a lower activation energy.

Two energy profiles of the same reaction: the catalysed one has a lower hump, 60 kJ instead of 120 kJ, and both end at -50 kJ

A catalyst lowers the hump, not the levels

$\Delta H$ does not change. Examples: iron for ammonia, platinum in car exhausts, enzymes.

Challenge

Hydrogen peroxide decomposes slowly: $\Delta H = -100\ \mathrm{kJ}$ , $E_a = 80\ \mathrm{kJ}$ (rounded). Manganese dioxide powder speeds it up a lot. Draw the diagram and the catalysed hump.

Try it yourself

Energy diagramDraw the energy diagram

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Energy, Rates and Equilibrium

1Energy in Reactions

Exothermic and Endothermic Energy Diagrams Enthalpy Change Activation Energy Recap - Hand Warmer

4Rates of Reaction

Collision Theory Concentration and Rate Temperature and Rate Surface AreaCatalystsRecap - Speed Trials

7Practice Problems

Recap - Methanol Plant Recap - Butane Lighter Recap - Limestone Kiln

2Bond Energies

Breaking and Making Bonds Delta H from Bond Energies Hess's Law Energy and Moles Recap - Fuel Value

5Equilibrium

Reversible Reactions Dynamic Equilibrium The Equilibrium Constant Writing K Solids and Liquids in K Recap - K Builder

3Changes of State

Heating Curves Melting and Boiling Energy of State Changes Recap - Ice to Steam

6Changing an Equilibrium

Le Chatelier's Principle Changing Concentration Changing Pressure Changing Temperature The Haber Process Recap - Factory Settings