1.10 Simple distillation
Distillation is used to separate liquids from one another. Visit this page to see distillation in the laboratory and look at an industrial scale process.
The water cycle..
Distillation: the action of purifying a liquid by a process of heating and cooling
Distillation on a very large scale...
You will be very familiar with the ideas illustrated in this graphic explaining the water cycle. The continual evaporation of water ( the solvent) from the sea ( the solution) - followed by cooling and condensation of the water vapour - means that the water that falls on the land is "distilled" and free from the salt
Activity 1
Explain in no more than 50 words why the water cycle makes the sea salty.
words to use:
dissolve, soluble, volatile, evaporate, condense
Activity 2 Laboratory distillation
- The word "retort" is used several times. Explain in your own words what a retort is .
- Explain why the water condenser has cold water fed in at the bottom and not the top.
- Distillation is one way of making drinking water from seawater. This is often an unfeasibly expensive way of producing drinking water. Explain why.
- A retort is a flask with a long neck which has a bend in it. This can be connected to a condenser so that gases leaving the retort can be collected and condensed.
- Cold water is fed into the bottom of the condenser to avoid creating a lager air gap at the top of the condenser.
- Obtaining pure water by distillation requires large amounts of energy to hear the solution. Energy costs.
Making spirits
Fermentation can be used to produce a dilute solution such as beer or wine. These solutions can be distilled to produce a spirit which contains much more alcohol and is consequently much more intoxicating.
Activity 3. Industrial Distillation
Study this engraving of the distillation of ethanol.
Make a copy of the drawing and label it with the same labels as the other simple distillation diagram.
Activity 4. Spot the deliberate mistakes
Study the video carefully. Two students are using distillation to extract pure water from some water soluble ink.
The students have made at least three deliberate mistakes.
Describe the mistakes and explain what they should have done instead in order to complete the task safely and correctly.
