Investigating the energy change when zinc reacts with copper(II) sulphate.

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Investigating the energy change when zinc reacts with copper(II) sulphate.



My aim is to see what happens to the temperature that the reaction between zinc and copper sulphate releases when we change the amount of zinc while keeping the amount of copper sulphate constant.


During the course of this experiment, I will be investigating to see what happens when I react some zinc with copper sulphate solution. I will be looking for an energy change during this reaction. The reason I am looking for an energy change is because I want to determine whether this reaction is an exothermic or an endothermic reaction. An exothermic reaction is a reaction that uses a small amount of energy (normally the energy supply is heat) to break bonds within molecules. The heat, transfers energy into the electrons making them vibrate more. When the electrons are vibrating more, the ions within the solution successfully collide with the electrons therefore knocking them out of the outer shell this is known as bond breaking. When the bonds are breaking, a large amount of energy is released. This energy can then be used industrially i.e. to run machinery and car motors. Evidence of an exothermic reaction is a warm test tube. An endothermic reaction is a reaction that requires a lot of energy to make bonds between two atoms. These bonds can either be covalent or ionic depending on what two non-metals or metal and non- metals are reacting. Endothermic reactions are to produce more stable compounds. Evidence for an endothermic reaction taking place, is a cold test tube.


The factor that I will be changing during this reaction is the amount of zinc I will be using. The maximum amount of zinc I am allowed to use is 0.5g due to environmental issues. I will be using powdered zinc instead of blocks of zinc is because of two reasons:

  • It will be easier to weigh an accurate amount of zinc better because of the small amount that we are allowed to use. Therefore our measurements have to be as accurate as possible.
  • Using powdered zinc increases the surface area for the copper sulphate to act upon so therefore due to the collision theory, there will be a number of more successful collisions so the rate of this reaction will be faster.
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The mass of zinc that I will be taking readings from are: 0.1g, 0.2g, 0.3g, 0.4g and 0.5g. For accurate results, I will be taking three repeats for each mass.

The factor that I will be keeping constant is the volume of copper sulphate which will be 50cm cubed. The reason I will be using 50cm cubed is because I need the maximum amount of zinc to completely react with the copper sulphate.


 I will pour 50cm cubed of copper sulphate in a polystyrene cup. The reason I will be using a polystyrene cup is because ...

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