Earth & Useful Resources

6.1 Rocks

recall that the surface of the Earth was molten for many millions of years and that eventually a thin crust formed but volcanoes erupted

Discuss the nature of the Earth’s crust and volcanoes. Use appropriate video materials.

recognise that igneous rocks form by crystallisation from magma

Discuss the nature of magma.

understand that crystal size is determined by the rate of cooling, slower cooling producing large crystals

Summarise salol results and lead pupils to an understanding of crystal size in igneous rocks.

recall that weathering of rocks produces particles which may be transported and form sediments

Discuss how rocks are broken down. Demonstrate expansion of water on freezing using small plastic bottle or water-soaked rocks.

describe how sediments become sedimentary rocks over very long periods of time

Discuss the time scales involved, including evidence from fossils.

explain that metamorphic rocks are formed by the action of heat and pressure on existing rocks over very long periods of time, e.g. limestone to marble

Discuss the extreme conditions of temperature and pressure which could change limestone into marble and where in the Earth’s crust this is likely to happen.

recall that rocks are grouped into igneous, sedimentary and metamorphic

Classify rocks on the appearance of texture, hardness and appearance.

appreciate that rock strata usually increase in age with depth

Discuss the formation of layers in sedimentary rock. Use appropriate video materials

recall that the Earth’s crust consists of sections called plates

Discuss plate tectonics

understand that the rocks can be: formed where plates move apart or volcanoes are active, deformed and/or recycled where plates collide and one sinks below the other and becomes molten

Consider the Rock Cycle

6.2 Industry based on Sodium Chloride

recall that hydrogen, chlorine and sodium hydroxide are produced by the electrolysis of concentrated aqueous sodium chloride and know how to test for these substances

Discuss how to obtain useful substances from salt and link to 215 (electrolysis). Compare laboratory experiment with the industrial process. Discuss the need to separate chlorine and sodium hydroxide produced.

recall the uses of sodium chloride in the food industry and for de-icing roads

Use appropriate video materials

6.3 Calcium Carbonate

appreciate that limestone, chalk and marble are naturally-occurring forms of calcium carbonate

describe the decomposition of calcium carbonate on heating to produce calcium oxide and carbon dioxide and know that this is an important industrial process

recall that calcium carbonate is used in the production of glass, cement and iron

describe the effect of water on calcium oxide and appreciate that the solution produced (limewater) is alkaline

recognise the difference between a solution and a suspension

understand why calcium oxide and calcium hydroxide are used to neutralise soil acidity and that a salt is formed in the reaction

6.4 Properties of the Halogens

recall the variation in colour and the trend in boiling point of the halogens

Demonstrate production of halogens and note their appearance.

recall that halogens react with metals to form metal halides

Demonstrate the reaction of Cl₂ with Fe and with Al.

describe the relative reactivity of the halogens as exemplified by their displacement reactions with halide ions

Review ideas about reactivity, for example, the reactivity series of metals.

explain the relative reactivity of the halogens as exemplified by their displacement reactions with halide ions

describe the use of chlorine in water purification and the manufacturing of bleaches and of iodine as an antiseptic

6.5 Useful Products from Crude Oil

recall that crude oil is formed by the long term effects of heat and pressure on marine deposits

Use appropriate video and display material.

recall that crude oil deposits are formed in porous rock beneath non-porous rock

Define a ‘fossil’ fuel.

recall that crude oil is a mixture of hydrocarbons

Define hydrocarbon. Introduce different types of hydrocarbon.

recall that methane is the main constituent of natural gas

recall the formulae of methane, ethane, propane and butane (not methylpropane)

Discuss structures, appreciating that C forms 4 covalent bonds.

recall the formulae of ethene and propene and draw the structures of these compounds

Introduce the idea of the C=C bond. Discuss structures, appreciating that C forms 4 covalent bonds.

describe the fractional distillation of crude oil

Discuss this method of separating mixtures of miscible liquids.

recall the uses of the various fractions obtained from the fractional distillation of crude oil

Discuss uses of fractions.

understand that the larger the hydrocarbon molecule, the higher the boiling point of the hydrocarbon and the less volatile it is at a given temperature

Define volatiltity.

describe the different fractions which are obtained and relate these to molecular size

explain that alkanes are saturated hydrocarbons and that alkenes are unsaturated hydrocarbons containing one double covalent bond between carbon atoms

recall that bromine water can be used to distinguish between alkanes and alkenes

Discuss the reactivity associated with the C=C bond. Compare this with the relative lack of reactivity of the C-C bond.

6.6 Cracking of Hydrocarbons and Use of Products

explain that cracking involves the breaking down of larger hydrocarbon chains in some fractions into smaller more useful ones

Describe cracking.

explain that some products of cracking have carbon-carbon double bonds

recall the conditions used in industry to crack fractions obtained from crude oil

recall that polymers are large molecules which can be formed by a combination of many smaller molecules

polymerise styrene in car body filler (Teacher demonstration)

explain how addition polymers are formed from unsaturated monomers (equations required but not conditions and mechanisms)

use models to show how polymers are formed from monomers

recall the uses and associated properties of poly(ethene), poly(propene) and poly(styrene)

Use appropriate video materials.

6.7 Ethanol

recall how ethanol is produced during the fermentation of carbohydrates

understand how to obtain a concentrated solution of ethanol by fractional distillation

understand that ethanol is produced by hydration of ethene

consider factors which are relevant to the choice of a method to be used in the manufacture of ethanol, e.g. the relative availability of sugar cane and crude oil

understand the role of fermentation in brewing, wine-making and bread making

understand that different amounts of ethanol are present in various drinks

consider the social issues and possible harmful effects of ethanol in alcoholic drinks

recall that industrial methylated spirit contains ethanol with added methanol to make it unfit to drink

understand the uses of ethanol as a solvent and as a fuel