Fractional Distillation
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Can you match country and drinking age?
Illegal, 16, 18, 19, 20, 21, no age limit
19
21
none
16
20
illegal 18
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Starter: quick question
Q: Which diagram shows the particles in the
following?
- salt solution
- pure salt
- pure water
- steam
B
A
C
D
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Aim
• By the end of this lesson I will be able to explain
how we can separate a solvent from a solute
Key words
• Solvent
• Solute
• Solution
• Distillation
• Condensing
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Solute, Solvent and Solution Solvent, solute, solution
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Review: What is a solution?
A solution is a special type of mixture that is made when one substance dissolves and mixes fully with another.
For example, a cup of instant coffee is a solution.
The solid that dissolves (e.g. coffee granules) is called the solute.
The liquid that does the dissolving (e.g. hot water) is called the solvent.
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Distillation
• How can you separate the solvent from the solids dissolved in a solution?
• The best method to separate and collect the solvent from the solution is distillation
• Distillation involves three stages: boiling condensing collecting
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7H Separation techniques – Distillation
water in
water out
thermometer
heat
heat proof mat
gas cools and condenses
condenser
liquid is
collected pure liquid
liquid
boils off
flask with
mixture
Boiling, Condensing and Collecting
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Fractional distillation in industry • Crude oil can be separated
into its different parts or by
fractional distillation.
• As the crude oil is heated,
the liquids in it get hotter.
• Each evaporates off at a
different temperature.
Liquid found
in crude oil
Boiling
point (0C)
petrol 60
kerosene 200
diesel 240
road tar 350
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Liquid found
in crude oil
Boiling
point (0C)
petrol 60
kerosene 200
diesel 240
road tar 350
1. Which liquid will reach its
boiling point first?
2. Which liquid will be the most
difficult to evaporate?
3. Why is it easier to turn
kerosene into a gas than
diesel?
4. All four liquids are used as
fuels. What is probably the
main hazard when separating
them by distillation?
1. Arrow A is pointing to the place where .................... happens.
2. At point B the hot vapour is cooling back to a liquid. This process is called ..................
3. ……. .…… goes into the distillation apparatus at point X and comes out again at point Y
4. Why is this substance necessary?
Plebary: Distillation
boiling
condensing
Cold water
So that water steam is changing back to liquid water and can be collected ©cgrahamphysics.com 2016
Key words • Solvent - The liquid that does the dissolving
• Solute - The solid that dissolves
• Solution - mixture that is made when one substance dissolves and mixes fully with another.
• Distillation - the action of purifying a liquid by a process of heating and cooling
• Condensing - cause to change from a gas or vapor to a liquid.
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