Question

A student carrying out out a Spectrophotmetric dtermination of copper in Brass lab experiment was in a hurry to finish. The student decided to omit the filtering step of the procedure because the brass solution did not appear very cloudy. It turned out that there was tin in the sample.

a) Did the omission of the filtering step cause a high or low result? Briefly explain.

b) Also during the filtering process some of the brass solution is absorbed by the filter paper. Would this cause a high or low result for percent copper? Briefly explain.

Answer 1

a)Did the omission of the filtering step cause a high or low result? Briefly explain.

Answer:- The omission of the filtration process would cause the higher percentage of the copper in the brass sample than actual present because the lead present in the solution would increase the absorbance of the solution this will lead to the higher concentration of the solution which is nothing but the higher concentration of the copper in the solution, therefore the percentage of the copper would be higher than actual present.

b) Also during the filtering process some of the brass solution is absorbed by the filter paper. Would this cause a high or low result for percent copper? Briefly explain.

Answer :- An absorption of the brass solution on the filter paper would not affect the percent of the copper in the brass in significant amount. Because the concentration of the solution would not affected by much difference. But in experimental procedural saying we can say that the percent of the copper would low.