I will keep the Bunsen burner in the same place on the table and I will put the test tube just above the tip of the little blue flame which is in the middle of the lighter blue flame, I will also put the same amount of polyomer wool in the top of each test tube.
Equipment:-
1 test tube rack,
5 test tubes,
1 scale,
1 Bunsen burner,
Some polyomer wool,
Heat mat,
Some zinc carbonate
Tongs
And some tweezers
Method:-
Once I have I got all of my equipment ready shown in the diagram on the previous page, I will number my test tubes 1 – 5 and weigh each one individually so I can take down the masses of the empty test tubes. I will then put in a level spatula of zinc carbonate in the test tube number one and two level spatulas in the second test tube and so on for the other test tubes. After this I will weigh each test tube once again to get their new masses. From this I will work out how much zinc carbonate is in each test tube, I can do this by taking the mass of the empty test tube take that away from the mass of the test tube plus the zinc carbonate this will give you the actual mass of zinc carbonate. Once I have done this I will find the expected mass of zinc oxide, I will do this by taking the mass of reactant and divide that by the formula mass of the reactant and times that by the formula mass of product. I will do this for every test tube. I shall heat all the test tubes until the substance has gone a very pale yellow, once this is done I will weigh all the test tubes (which are still containing the solid) after heating to get the new mass. I will then find the mass of zinc oxide obtained by taking the mass of the empty test tube away from the mass of test tube after heating. Once I have done this I can find the percentage yield of zinc oxide to do this you have to get the actual mass and divide that by the expected mass and times it by 100.
Prediction:-
The more zinc carbonate we start with the more zinc oxide we will get. If we start with 1g of zinc carbonate we will get 0.65g of zinc oxide.
This is because there are more zinc carbonate particles to react with the oxygen and therefore more zinc oxide will be present.
Results:-
A table to show the thermal decomposition of zinc carbonate
Before heating After heating
Analysis:-
My results tell me that as I increase the amount of zinc carbonate being reacted, the amount of zinc oxide increased. I know this because my graph shows that as my predicted mass rises so does my actual result thus proving that my prediction was correct.
The general trend of my graph is upwards. There is a three point rise and then a drop and then a rise again. My data supports my prediction as the amount of ZnO3 increases so does the amount of ZnO.
Evaluation:-
When looking at my graph my results closely match my predicted masses, and so I think that my results are accurate. I could improve them by working out my results/predicted masses with a better set of scales, ones that measure to three decimal places. I think that I have one anomaly, which I have circled on my graph. I think that it is possible that I have this because I may have not given the reaction enough time in the Bunsen burner flame, which could have left some un – reacted ZnCo3 which wouldn’t give me an accurate result for that one. I think my experiment went well, but if I could do it again, I would have a wider scale of measurements, ranging from as close as 0.5g to perhaps 5g then I could plot a more detailed graph, and therefore have better and more accurate results. Yes my data is reliable as it does support my conclusion.
