Soap Experiment(Complete) Flashcards
What is the difference between a fat and an oil?
Fats are solids at room temperature.
Oils are liquids at room temperature.
Animal fats are saturated.
Plant oils are unsaturated.
What are the benefits of using unsaturated fats and oils?
They do not produce cholesterol.
Will not block arteries.
What is another name for the base hydrolysis of esters?
Saponification.
What is another name for saponification?
Base hydrolysis of esters.
How do you carry out the saponification experiment?
Place sunflower oil into a pear shaped flask.
Add NaOH.
Add ethanol to dissolve the fat.
Add the anti-bumping granules.
Reflux for 30 minutes.
Swirl to remove substances stuck to the sides of the glass.
Cool and rearrange for distillation.
What is a precaution associated with NaOH?
Caution- caustic.
It will burn the skin.
What is the purpose of adding in ethanol?
It will dissolve the fat.
What is the purpose of adding the bumping granules?
To prevent the formation of large bubbles which may cause damage to the apparatus.
How long do you reflux for?
30 minutes.
What are the reasons for refluxing?
To give time for the reaction to take place.
To prevent the loss of volatile components.
Draw a diagram of the set up for a reflux.
In manual.
Describe how the distillation process occurs.
Distill off the alcohol which is there to dissolve the lipid and make it react faster.
Pour the contents of the flask into concentrated brine solution.
Soap is insoluble in brine so it precipitates out.
Filter the mixture by vacuum filtration.
Rinse with cold deionised water to remove the NaOH.
Excess NaOH and glycerol stay in solution and pass through the filter into the flask.
Draw a diagram of the set up for distillation.
In manual.
Draw the formula for the production of soap.
In manual.
What does soap do when coming in contact with soft water?
It forms a lather
What does soap do when coming into contact with hard water?
It forms a scum- calcium stearate.
Why is it desirable to remove the ethanol after the reflux?
It is easier to isolate the soap.
It will maximise the yield.
Why was a minimum of hot water used to dissolve the residue from the distillation?
To maximise the soap precipitating out.
What is brine?
Concentrated salt solution.
Describe how the soap can be isolated from the mixture of soap and brine.
Filter.
Give one precaution that helps ensure that the soap is free of sodium hydroxide.
Wash with ice- cold water.
Name the type of reaction which occurs during the reflux stage of the preparation.
Base hydrolysis of esters/ saponification.
Describe how a pure sample of soap was obtained from the reaction mixture.
Dissolve residue in a minimum of boiling water.
Pour onto the brine.
Filter or wash with little ice water.
What is the relative molecular mass of glycerol tristearate?
890.