RATES OF REACTION - TEMPERATURE

1. Holes in car bodies can be filled using Fibreglass resin.This product comes in three parts.

    1. resin - this is a liquid
    2. filler - this is a powdered solid
    3. paste - this is a jelly like material

The three parts are mixed together and then put into the hole in the car body.

A chemical reaction takes place and the mixture sets solid.

The time it takes for the mixture to turn solid is called the 'setting time'.

Look at the Table. It shows the results of an investigation into the setting times of different mixes.

All the experiments were carried out at 15oC.

Experiment number
volume of resin / cm3
 mass of filler / g volume of paste / cm3 setting time / min
1 10 20 0 800
2 10 20 2 12
3 10 20 4 6
4 20 20 2 24
5 5 20 2 ?

  1. Use the information in the Table to explain what the paste does. [2]
  2. In experiment 5 what is the setting time ? [1]
  3. Experiment 3 is repeated. This time a temperature of 30oC rather than 15oC is used. Explain how and why the setting time will change. Use ideas about the movement of particles. [4]
  4. If the repairs were carried out in the winter with a temperature of only 5oC rather than 15oC would you need more or less paste ? Explain why. [2]

2. You are given

    • 5 cm lengths of magnesium ribbon
    • dilute sulphuric acid
    • a thermometer

Describe;

  1. how you would find out the effect of temperature on the rate of reaction between dilute sulphuric acid and magnesium.
  2. what apparatus you would use.
  3. what measurements would you make and what would you do with your results.

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