Jeevan Karthick Thiyagarajan 8H
Chemistry Week 4 HW
Experimental Write-Up on the Reaction Between Copper and Sulphur:
Aim: To find out the end product of a chemical reaction between Copper (Cu) and Sulphur (S).
Independent Variable: Sulphur powder + copper coil
Dependent Variable: Product of the reaction
Control Variables: Length of the copper coil + the mass of the sulphur powder
Hypothesis: I predict that when Copper and Sulphur are heated in the presence of a small volume of oxygen, the two elements will chemically react to produce the substance Copper sulphate (CuSO4) a blue-coloured, compound (chemical formula: Cu + S + 2 O2 -> CuSO4). In the absence of oxygen (e.g. a vacuum), Copper and Sulphur will react to form copper sulphide (Cu2S) - a chalky compound usually in the colour of blue (chemical formula: 2 Cu + S -> Cu2S). Sulphur oxide may also form (in the presence of oxygen during the reaction) which is a choking gas that has a pungent odour. For the purpose of this reaction, we are preventing as much oxygen as possible and therefore, I predict that more copper sulphide will be formed.
This is a preview of the whole essay
- Sulphur powder
- Copper coils
- Cotton wool
- Bunsen burner
- Heatproof mat
- A spatula full of Sulphur powder and a small piece of the Copper coil was placed into an empty test tube.
- Some cotton wool was pushed into the top of the test tube to prevent as much gas as possible from exiting the test tube.
- Observations of the substances inside the testable were recorded. And the mass of all the equipment inside a beaker was recorded.
- A bunsen burner was lit and set to a roaring, blue flame and the test tube was held directly above the flame at a 45-degree angle away from people using tongs.
- The test tube was held above the flame until the sulphur gas had risen above the copper coil.
- The test tube was allowed to cool and emptied and observations of its contents were recorded. The mass was also measured and recorded.
- All people must stand and all chairs must be tucked in.
- Ties should be tucked into shirts to prevent catching fire and long hair must be tied back.
- All bags must be underneath tables to prevent trip hazards.
- Safety goggles must be worn at all times.
To conclude, my prediction was correct and Copper sulphate was formed (a brittle blue compound). This was most likely as the volume of oxygen in the air inside the test tube was trapped by the cotton wool art the top of the test tube and the flow of oxygen into the test tube was also slowed down by the cotton wool the prevent as much oxygen as possible from reacting with the sulphur to make sure this is a fair experiment. Additionally, the mass of the contents remained the same from before and after the experiment. This agrees with the Law of Conservation of energy and therefore, we can assume that very little oxygen entered the test tube as there is no more mass added to the contents during the reaction. This therefore proves that our experiment is reproducible as the results we acquired matched the expected set of results.
Overall, I strongly believe that this experiment was very successful as we were able to acquire a valid and reproducible set of results without any injuries. One way I think there were errors in our results was the fact that there was some oxygen present during the reaction which created a foul odour. I think that we could mitigate this issue by creating a vacuum whilst conducting our experiment to make sure there are no other particles. The next I conduct this experiment, I would try and repeat it several times to make sure that there are no other substances created or I would try to at least use a balloon on the top of the test tube instead of the cotton wool as silicon is much better at keeping out gases than cotton wool. All safety rules were followed during this reaction and nobody was hurt. On a final note, this experiment was very successful and is reproducible too.