Organic Chemistry Laboratory (CHMS3101)
BSc, Chemistry - CHMS
Semester: First Semester
Level: 300
Year: 2016
REPUBLIC OF CAMEROON REPUBLIQUE DU CAMEROUN
Peace-Work-Fatherland Paix-Travail-Patrie
THE UNIVERSITY OF BAMENDA UNIVERSITE DE BAMENDA
P.O. Box 39 Bambili
Faculty of science Department of chemistry lecturers: Awantu/Noudo
Course code: CHMS3101 Course title: organic chemistry laboratory
Date: 03/03/2016 hall: PBA 07 time: 11h00-13h00 (2 hours)
Instructions: Please answer all questions.
Exercise 1 (12marks)
a) Give four accurate equipments that can be used to perform the liquid-liquid extraction. 2pts
b) Give four safety equipments that can be found in a chemistry laboratory 2pts
c) Give the principle of extraction of benzoic acid from a mixture of benzoic acid + dichloromethane,
using 5% sodium hydroxide and 5 ml of hydrochloric acid. 3pts
d) A mother solution was prepared in dissolving 3g of benzoic acid in 250ml of dichloromethane. To do
the extraction of our benzoic acid we have used only 75ml of our mother solution mixed with 5%
sodium hydroxide and 5ml of hydrochloric acid. Determine the percentage yield of the reaction
knowing that the mass of benzoic acid + filter paper obtained is 1.60g.
Given; filter paper 1.2g 5pts
Exercise 2 (12marks)
This year, we have done the synthesis of Aspirin in Chemistry laboratory.
a) Give the name of reagents that are used to produce Aspirin 2pts
b) Give four accurate equipments that can be used to perform the synthesis of Aspirin. 2pts
c) Give the name of four forms of Aspirin that can be found in the Pharmacy. 2pts
d) Give the principle of synthesis of Aspirin (equations). 6pts
Exercise 3 (11marks)
The chemistry laboratory of the Faculty of Science of the University of Bamenda produces powder soap. During
the practical, there was a reagent container thatcontained a solution of sodium carbonate ( Na
2
CO
3
) of unknown
concentration and we can decide to determine its concentration.
a) Which laboratory technique can be used to determine the concentration of this solution? lpt
b) Is sodium carbonate a monobase or a dibase? Justify your answer, lpt
c) Knowing that we can Use 15ml (VI) of 0.25N HC1 and 10 ml (V2) of sodium carbonate' solutions,
determine the normality and molarity of Na
2
CO3, each with it error. 3pts
Given: ∆V1= 0.2ml, ∆V2= 0.1ml, Na=23
d) Give the principle of Saponification (equation). 2pts
e) To make our powder soap, we have used 41 of Ester having a density of - 0.85 and a molecular mass of
218g/mol, mixed with 1245cm
3
of solution of Sodium hydroxide. Determine the concentration of the
solution of Sodium hydroxide. 4pts
Good luck
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