# Displacement Reaction

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Displacement Reaction

The aim of my experiment is to find out what happens to the heat of

the zinc and copper sulphate solution when one of the variables is

changed.

Key variables:

§ amount of copper sulphate solution

§ amount of zinc

I am going to investigate what happens to the temperature of the zinc

and copper sulphate solution as the amount of zinc is increased. The

equation to show this reaction is:

Zn + CuSO4 ® ZnSO4 + Cu

The enthalpy change for the reaction is:

²H = -217kJ mole ¹

This means that if 1 mole of solution is used of each substance, the

heat given off will be 217,000 Joules.

Apparatus:

§ 1 test tube

§ 20ml of copper sulphate solution for each experiment

§ Zinc

§ Rubber bung

§ Thermometer

Prediction:

I think that as the amount of zinc is increased, the temperature of

the solution will also increase. I have used the following formula to

predict some results of this experiment.

q = Q

mc

where q = temperature rise, Q = quantity of heat, m = mass of solution

(20g) and c = the specific heat capacity of water which = 4.18Jg ¹K ¹.

65g Zinc ® 217000 joules

1g Zinc ® 217000 = 3338 joules

65

Therefore for 1g of zinc:

3338 =39°c rise

20x4.18

I can now use this formula proportionately to predict results for my

investigation.

For 0.3g of zinc:

0.3 x 39 = 12°c rise

For 0.5g of zinc:

0.5 x 39 = 19.5°c rise

For 0.7g of zinc:

0.7 x 39 = 27.3°c rise

For 0.9g of zinc:

0.9 x 39 = 35.1°c rise

I have used this information in order to predict the results of the

temperature rise I expect to see as the amount of zinc is increased. I

have also used this information to plan my experiment.