GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating column

KeywordsKeywords:: Fractionating column, fractionsFractionating column, fractions

Prior Learning:Prior Learning:Know what a hydrocarbon & alkane is.Know what a hydrocarbon & alkane is.

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating columnLearning Objectives: Identify and explain • That crude oil is separated using fractional distillation.• The properties of each fraction and how they relate to chain length.• Which fractions make useful fuels and why.

I will be successful in this lesson if I can: (Level C)• State that crude oil is separated into fractions by fractional distillation.• List how the properties change from small chain fractions to long chain fractions.• State which fractions are useful fuels.

(Level A)• Explain the key steps involved in fractional distillation.• Relate the trend in properties to molecular size.

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating column

What fuels have you used already today?

Transport

Petrol

Diesel

Gas

Heating

Oil

Gas

Cooking

Gas

Charcoal

Lighting

Gas

Oil

Even electricity is likely to have been produced by fossil fuels

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating column

Consider this diagram & these keywordsSEPARATE

MIXTURE

BOIL

HEAT

MIXTURE

HEAT

BOIL

SEPARATE

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating column

Fractional DistillationFractional Distillation

What is it???

http://www.youtube.com/watch?http://www.youtube.com/watch?v=26AN1LfbUPc&feature=player_embv=26AN1LfbUPc&feature=player_embeddededded

1. Where is crude oil formed and how is it extracted?

2. What is crude oil?

3. What are the simple state changes used in this distillation?

4. What property of the crude oil fractions cause them to separate in the fractionating column?

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating column

Fractional DistillationFractional Distillation1. Produced deep in the earth from the long term heat and pressure of

animal and plant remains. It is either pumped to the surface or rises due to its own pressure.

2. Crude oil is a mixture of many hydrocarbons.

3. Condensation (gas to liquid) and evaporation (liquid to gas).

4. Boiling point will separate the fractions. The lighter fractions (less smaller carbon chains – smaller molecules, lighter in colour) have a lower boiling point and so will move up the fractionating column.

Inside the column there are many trays with holes to let gases through. Vapours move up the column & condense on the trays when they reach their bp. Fractions with low bp burn more easily which makes them useful as fuels.

What would you expect to collect from the top of the column?What would you expect to collect from the top of the column?

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating column

Fractional Distillation Demonstration1.1. Soak mineral wool in crude oil and place in a Soak mineral wool in crude oil and place in a boiling tube.boiling tube.2. Fix the thermometer bung & side arm.2. Fix the thermometer bung & side arm.3. Gently heat the boiling tube.3. Gently heat the boiling tube.when the temperature stabilises at about 80when the temperature stabilises at about 80ooC C then 1 type of fraction is separated.then 1 type of fraction is separated.4. Change the collecting tube as the temperature 4. Change the collecting tube as the temperature rises again.rises again.5. Repeat step 4 four times collecting five fractions5. Repeat step 4 four times collecting five fractions& leaving the residue in the boiling tube.& leaving the residue in the boiling tube.6. Tip each fraction onto mineral wool & ignite.6. Tip each fraction onto mineral wool & ignite.

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating column

Fractional Fractional DistillationDistillation

Once fractions are collected,

they need more refining before they

can be used.

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating column

Read p56 of text

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating column

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating columnOver 85% of crude oil is used as a fuel for heating and transport. Only 8% is used to make plastics and other chemicals.

A fuel is a substance that reacts with oxygen to produce useful energy.

A large amount of oil is used as fuel because the hydrocarbons in the fractions burn easily and produce a large amount of useful energy.

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating columnLiquid petroleum gas (LPG) contains propane and butane. They are stored under pressure in metal cylinders.

LPG is used for heating and cooking, especially where piped gas cannot be used, such as camp sites and boats.

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating columnGasoline is one of the most important fractions because it is used as a fuel for cars.

The gasoline fraction must be refined before it can be used in cars as petrol. Impurities are removed, and chemicals are added to ensure the engine runs smoothly.

In the past, these chemicals were lead compounds but because of lead’s harmful effect on health and the environment, they have been replaced by safer compounds.

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating columnNaphtha is a very important fraction that has many uses. For example, it is:

added to petrol and other fuels.

a raw material (feedstock) in the production of chemicals and plastics

used as a cleaning fluid and industrial solvent(a substance that can dissolve another substance)

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating columnKerosene, also called paraffin, is mainly used as aviation fuel for jet aircraft. It is also used in central heating systems, lamps and stoves.

Diesel is mainly used as a fuel for lorries, buses and cars, and in some boats.

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating columnLubricating oil, as its name suggests, is used as a lubricant in products with moving parts, such as engines.

Fuel oil is a heavy fraction used as a fuel for large industrial boilers, oil-fired power stations and ships.

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating columnResidue contains paraffin waxes and bitumen, the heaviest product to come from an oil refinery.

Paraffin waxes (not the same as paraffin/kerosene) are used in candles and waterproofing.

Bitumen is used in road construction and waterproof roof material.

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating column

GCSE Core Chemistry

Exam tip; You MUST be able to explain how fractional distillation Exam tip; You MUST be able to explain how fractional distillation works. Small molecules (compounds with low bp) are at the top of works. Small molecules (compounds with low bp) are at the top of

the fractionating columnthe fractionating columnLearning Objectives: Identify and explain • That crude oil is separated using fractional distillation.• The properties of each fraction and how they relate to chain length.• Which fractions make useful fuels and why.

I will be successful in this lesson if I can: (Level C)• State that crude oil is separated into fractions by fractional distillation.• List how the properties change from small chain fractions to long chain fractions.• State which fractions are useful fuels.

(Level A)• Explain the key steps involved in fractional distillation.• Relate the trend in properties to molecular size.