Question

In your experiment today will the percent yeild of calcium carbonate be higher, lower, or unchanged if:

(a). The torn - off - corner of the filter paper is discarded instead of placing it in the cone. Explain.

(b). The graduated cyliner is not rinsed after transferring the sodium carbonate solution to the beaker. Explain.

(c). The calcium carbonate precipitate is weighed today instead of the next lab period? Explain.

Answer 1

a) The torn - off - corner of the filter paper is discarded instead of placing it in the cone. In this case some of the calcium carbonate may be lost along with discarded filter paper. So percentage yield of calcium carbonate will be lower.

b) The graduated cyliner is not rinsed after transferring the sodium carbonate solution to the beaker. It does not effect the percentage the percentage of calcium carbonate. Answer is unchanged.

c) The calcium carbonate precipitate is weighed today instead of the next lab period.

In this case we may get higher yield. Because if precipitate is weighed today it may contains some moisture which leads to higher percentage of calcium carbonate yield.