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Question

I have three problem solving.

First, Calculate the amount of crystals recovered if a 2.315 g sample was reduced to 73.00% of its mass after recrystallization.

Second, Calculate the percent purity of a 5.47 g mixture whose recovered crystal amounted to 2.75 g with a percent purity of 97.3%.

Third, How much sample is needed to recover 1.1101 g crystals having a percent recovery of 66.00%?

Answer 1

1) Let x = amount of xtals recovered after purification

(x/2.315)*(100) = 73 x = (73)(2.315)/100 = 1.690 g

2) 5.47 g crude ------> 2.75 g @ 97.3% purity

(0.973)(2.75) = 2.68 g

(2.68/5.47)*100 = 49.0% purity

3) (1.1101/x)*100 = 66.00% (1.1101)(100) = 66x (1.1101)(100)/66 = x = 1.6820 g