Please help with question 1.7- 1 Crystallization A chemist crystallizes 17.5 g o
ID: 1088428 • Letter: P
Question
Please help with question 1.7- 1 Crystallization A chemist crystallizes 17.5 g of a solid and isolates 10.2 g as the first crop and 3.2 g as the second crop. (a) What is the percent recovery in the first crop? (b) What is the total percent recovery? 1.6 1.7 A student crystallized a compound from benzene and observed only a ferw crystals when the solution cooled to room temperature. To increase the yield of crystals, the student chilled the mixture in an ice-water bath. The chiling greatly increased the quantity of solid material in the flask. Yet when the stu- dent filtered these filter paper. Explain this student's observations. The solubility of acetanilide in hot water (5.5 g/100 mL at 100') is not very great, and its solubility in cold water (0.53 g/100 mL at 0') is significant. What would be the maximum theoretical percent recovery (first crop only) from the crystallization of 5.0 g of acetanilide from 100 mL of water (assuming the solu- tion is chilled to 0')? crystals with vacuum, only a few crystals remained on the 1.8 1.9 A 1.0 g sample of benzoic acid is contaminated with 0.05 g of salicylic acid Solubilities in water of the two compounds are given in the following Solubility at 100'C (g/o Comnound Solubility at 20 C(Explanation / Answer
Answer 1.6)
Given data:
Mass of Crude product = 17.5 g
Mass of the product isolated in First Crop = 10.2 g
Mass of the product isolated in First Crop = 3.2 g
Total Mass of the product isolated = 10.2 + 3.2 = 13.4 g
a) % Recovery of product in first Crop = (Mass isolated in first crop / Mass of Crude) x 100
= (10.2 /17.5)*100
= 58.27%
% Recovery in First Crop is 58.27%.
b) Total % Recovery = (Total mass recovered / Mass of Crud) * 100
= (13.4 / 17.5) * 100
=76.57%
Total % Recovery is 76.57%
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