The three experiments gave slightly different results for the mass of copper made.This was caused by experimental error.Suggest two causes of experimental error in these experiments

Shorten to 100 words: The experiment includes the process of decantation between copper solid and the supernatant. During this procedure, some copper solid was lost when the supernatant solution was separated from the precipitate. This could have been due to the incomplete separation of the solution and the precipitate which could have led to the loss of copper solid recovered (final mass) and therefore reduction of percentage yield. Another possible source of error could be that the reaction between CuSO4 and Zinc powder was incomplete. This indicates that the amount of zinc added to the solution was less than the stoichiometric amount required to completely displace all the copper ions. As a result, the actual amount of copper solid produced was less than the theoretical yield. This discrepancy reduced the percentage yield of copper.

The experiment involved a series of reactions to produce copper solid from the copper compound copper chloride dihydrate. The proportion of copper in CuCl2.2H2O was 0.0588g and the final mass of copper solid recovered was 0.0165g. Therefore, the percentage yield calculated was 28.1% suggesting a large percentage of copper was lost. An alternative reaction pathway such as replacing zinc powder with a stronger reducing agent like aluminium or magnesium could increase the yield of copper as it reduces copper ions more effectively. The colour changes observed during the experiment are the result of the varying oxidation states of copper and the formation of different copper compounds. The experiment started off with a blue-green powder of CuCl2.2H2O which turned into bright blue transparent solution after being dissolved in water. The addition of NaOH produced a light blue precipitate in solution indicating the formation of Cu(OH)2. Upon heating the solution, the precipitate transformed into a black solid, CuO. Then, H2SO4 dissolved the CuO, producing a transparent and light blue solution of CuSO4. Finally, the copper ions in solution were reduced by zinc powder, forming a reddish-brown copper solid. The experiment includes the process of decantation between copper solid and the supernatant. During this procedure, some copper solid was lost when the supernatant solution was separated from the precipitate. This could have been due to the incomplete separation of the solution and the precipitate which could have led to the loss of copper solid recovered (final mass) and therefore reduction of percentage yield. Another possible source of error could be that the reaction between CuSO4 and Zinc powder was incomplete. This indicates that the amount of zinc added to the solution was less than the stoichiometric amount required to completely displace all the copper ions. As a result, the actual amount of copper solid produced was less than the theoretical yield. This discrepancy reduced the percentage yield of copper. Overall, the low percentage yield of copper obtained suggests this method was inefficient at extracting copper from copper compounds. The experimental method was too complex, time-consuming, and required a significant number of reagents which would make it economically and environmentally impractical for the large-scale extraction of copper from ores. Alternative methods may need to be considered for commercial purposes. Reduce the above paragraph to 300 words

The percentage of copper and oxygen in samples of CuO obtained by different methods were found to be the same. The illustrate the law ofSelect an answerAconstant proportionsBconservation of massCmultiple proportionsDreciprocal proportions

Calculate the mass in grams of 26.6mol of copper(Ⅰ) chromate. Be sure your answer has the correct number of significant figures.

The student added excess copper oxide. Describe the steps that the student could include in the method to find the mass of copper oxide that reacted.