QUESTIONS
1. Find the moles of cyclohexane formed in the experiment. (2 marks)
•Mass of cyclohexene obtained: 11 ml x 0.811g/ml = 8.921g
•Number of mol: mass/molar mass
8.921g / 82.143g/mol = 0.1086 mol
2. Calculate the expected mass of pure product cyclohexane using the number of moles
cyclohexanol used in the experiment based on the equation. (2marks)
•Mol obtained: 0.1086mol
Molar mass of cyclohexene: 82.143g/mol
Expected mass of pure cyclohexene: 82.143g/mol x 0.1086mol = 8.9207 g
3. Show the calculation for the percentage yield/conversion of cyclohexanol to
cyclohexene. (2marks)
•Mass of cyclohexene obtained/ Mass of cyclohexene theory
•8.921 / 8.9207 x 100% = 100%
4. Suggestion another simple chemical test for the product instead of KMnO4(aq) and
state the observation. (2marks)
•Instead of using potassium permanganate, the presence of alkene group can be
tested by the reaction of bromine in dichloromethane. Bromine reagent is reddish-
orange in colour. When it is poured slowly into the alkene, bromine reacted with
alkene to form a colourless dibromide. When bromine is consumed, it colours will
faded. So, if the colour of bromine reagent decolourised, means the alkene group
is present.
5. Draw the products that would be obtained by the dehydration of the following
molecules and state which are minor and major products. (4marks)
a. 2-heptanol
