Report
Evaluation
TOTAL
Chem 209 Lab Report
Experiment 2: Crystallization
Student Name______________
Date_____________
Student ID #_______________
Section___________
A-Selection of a crystallizing solvent
I-Purpose:
II-Table of Reagents:
Compound
Formula
M.Wt.
(g/mol)
Melting point
(ºC)
Boiling point
(ºC)
III-Results:
Compound
Water
Cold Hot
Toluene
Cold Hot
Ligroin
Cold Hot
Best solvent for
Recrystallization
IV-Discussion of Results:
B- Recrystallization of Acetanilide
I-Purpose:
II-Table of Reagents:
Compound
Formula
M.Wt.
(g/mol)
Melting point
(ºC)
Boiling point
(ºC)
III-Results:
Structure of
acetanilide
Mass used
(g)
Mass recovered
(g)
% Recovery
Acetanilide
Melting point
Crude
Pure
IV-Discussion of Results:
C- Decolorization of Brown Sugar
I-Purpose:
II-Table of Reagents:
Compound
Formula
III- Observation:
IV-Discussion of Results:
M.Wt.
(g/mol)
Melting point
(ºC)
Boiling point
(ºC)
E-Answer to Questions:
1. Would you recommend suction filtration for a solution in which ether is the
solvent? Explain.
2. Why is it important to minimize evaporation during the filtration of the hot
solution?
3. An organic chemist has an impure solid (X) which is soluble in water to the
extent of 3 g per 100 ml of water at room temperature and 15 g per 100 ml of
water at 100 °C. 10 g of X has 1 g of impurity A (A has the same solubility in
water as X) and 0.40 g of impurity B (B is insoluble in water). How could you
purify X? How many grams of pure X could be obtained after one
recrystallization from water?
4. The solubility of an organic material A in 100 ml of acetic acid is shown in
the following table:
Temperature
(°C)
20
30
60
80
100
110
118
Mass
(g)
0.15
0.20
0.25
0.40
0.50
0.65
3.00
Two students recrystallized 10 g samples of A from acetic acid, the first
dissolving A at 100 C and filtering at 20 C, the second dissolving the acid at
110 C and filtering at 30ºC. Calculate the quantity of acetic acid each student
was required to use and the percentage recovery of A possible in each case.