1. 2.8.2 – Factors that influence the rate of reaction
e. demonstrate an understanding of the role of catalysts in providing alternative reaction routes of lower activation energy and draw the reaction profile of a catalysed reaction including the energy level of the intermediate formed with the catalyst
f. carry out simple experiments to demonstrate the factors that influence the rate of chemical reactions, eg the decomposition of hydrogen peroxide.
Connector:
Draw and fully label the reaction profile for an endothermic reaction
Sketch and fully label Maxwell-Boltzmann distribution curves to show the effect of an increase in temperature on the energy of the particles in a gaseous reaction
Explain how a catalyst affects the rate of a reaction
Crowe2009

2. Catalysts
A catalyst is a substance that speeds up a chemical reaction.
A catalyst is not used up in the reaction it catalyses, and so can be used over and over again.
"A catalyst provides an alternative route for the reaction with a lower activation energy."

3. More about catalysts .1
"A catalyst provides an alternative route for the reaction with a lower activation energy."
Ea1 is the activation energy leading to the formation of an intermediate complex.
Ea2 is the activation energy for the change of the intermediate complex into products.
Ea3 is the activation energy of the uncatalysed reaction.

4. More about catalysts .2
The catalyst combines with one of the reactants to form a intermediate known as a reactant-catalyst complex (an activated complex) which then reacts with another reactant to form the products – hence two humps.
reactant-catalyst complex

5. More about catalysts .3 A + B C + D A + A- A- + B C + D + Ea3 Ea1 Ea2
reactant-catalyst complex

6. Measuring reaction rates
Marble chips
Glass tube
Gas syringe
Hydrochloric acid Mg
HCl
Research these other methods you need to know about:
titrimetric analysis
colorimetric analysis
conductimetric analysis

7. Iodine clock - demo http://www.123helpme.com/view.asp?id=120541

8. Practical 2.10 Factors that influence the rate of chemical reactions
Each group of students will need:
Eye protection
3x Boiling tubes and a rack
10 cm3 measuring cylinder
spatula
Manganese(IV) oxide HARMFUL
Lead(IV) oxide TOXIC
Copper(II) oxide HARMFUL
20 vol H2O IRRITANT
Washing-up liquid