This experiment has also been trialled using KMnO4(aq) (0.0005 mol dm ) as the indicator. This turns from purple to colourless while unsaturation is still present. The procedure is the same as for bromine water, but portions of the potassium permanganate are added with swirling until the mixture fails to produce a colourless solution. The mixture requires more and more swirling as the amount of potassium permanganate increases. Warming fats in the Volasil using a beaker of hot water helps the fat dissolve and also speeds up the reaction.
This experiment should be done in a fume-cupboard with ready filled burettes.
Background theory
Saturation and unsaturation.
Classic chemistry experiments
21
Safety
Wear eye protection.
Answers
1. Depends on what is supplied.
2. Weighing the fats and oils and calculating the exact amount of bromine water used per mole.
3. Unsaturated compounds contain double covalent bonds.
Classic chemistry experiments
Unsaturation
in fats and oils
Introduction
Advertisements often refer to unsaturated fats and oils. This experiment gives a comparison of unsaturation in various oils.
Burette containing bromine water
Conical flask
Oil and Volasil
White tile
What to record
The Term Paper on Fat And Water- Soluble Vitamins
Fat and Water- Soluble Vitamins Research the functions, importance, and role of fat- and water-soluble vitamins. Identify the vitamin classification. Why are vitamins an important part of daily nutrient intake? What are fat-soluble vitamins? What are high nutrient sources of these vitamins? What are the functions, benefits, deficiency risks, and toxicity risks of fat-soluble vitamins? What are ...
Volume of bromine water required for each oil.
What to do
1. Using a teat pipette, add five drops of olive oil to 5 cm of Volasil in a conical flask. –3
2. Use a burette filled with a dilute solution of bromine water (0.02 mol dm ) (Harmful and irritant).
Read the burette.
3. Run the bromine water slowly into the oil solution. Shake vigorously after each addition. The yellow colour of bromine disappears as bromine reacts with the oil. Continue adding bromine water to produce a permanent yellow colour. 4. Read the burette. Subtract to find the volume of bromine water needed in the titration.
5. Repeat the experiment with: five drops of cooking oil (vegetable) and five drops of cooking oil (animal).
Safety
Wear eye protection.
Questions
1. Which sample is the most saturated and which is the most unsaturated? 2. This comparison is only approximate. How could the method be improved? 3. What does unsaturated mean?
