1. Rates of Reactions

2. Factors affecting the rate of reaction
The surface area
The concentration of the reactant
The temperature at which the reaction is carried out
The use of a catalyst
The influence of light

3. 1. Rates of Reaction - Surface Area
The more finely grated/powdered a solid is the faster it reacts.
Increased surface area

4. Limestone reacted with hydrochloric acid
Calcium carbonate + hydrochloric acid
calcium chloride + water + carbon dioxide

5. Rate of Reaction The reaction is faster at the start.
The gas is produced faster with the smaller marble chips – increased surface area.
The loss of mass is the same.
At the end the loss of mass slows down as the reactants are used up.

6. 2. Concentration of Reactant
Magnesium and hydrochloric acid
magnesium chloride + hydrogen

7. Rates of Reaction - Concentration
The curve is steeper for the higher concentration – it is faster.
The total volume of hydrogen produced at the end is the same.

8. 3. Rates of reactions - Temperature
A reaction can be made to go faster or slower by changing the temperature.
Food is stored in a fridge to decrease the rate of decay/oxidation.
Sodium thiosulfate + hydrochloric acid
sodium chloride + sulfur + sulfur dioxide + water

9. Effect of Temperature
The rate of a reaction increases when the temperature is increased.

10. Homework
Study for exam
Complete worksheet
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