IGCSE CHEMISTRYPREPARED BY MR DANIEL

LESSON 2

Learning outcomesDescribe and explain the carbon cycle to include the processes of photosynthesis, combustion, and respirationWrite the complete word equations for photosynthesis, complete combustion of air, and respiration.State CO2 and CH4 as greenhouse gases and explain how they contribute to climate changeState the formation of CO2 as a product of complete combustion, respiration, decay, decomposition of carbonates, and as a product of acidic reaction with carbonates(as in limestones)

Lesson 2:Carbon CycleKeywords:PHOTOSYNTHESISDISSOLVINGRESPIRATIONDECAY/DECOMPOSITIONCOMBUSTIONHUMAN ACTIVITIES

B2b Topic 3: Energy FlowLesson Objectives:Describe carbon cycle by producing a poster of the carbon cycle using the keywords Photosynthesis and what affects the rateThe carbon cycleClimate changeFood production

Lesson 2:Carbon CycleKeywords:PHOTOSYNTHESISDISSOLVINGRESPIRATIONDECAY/DECOMPOSITIONCOMBUSTIONHUMAN ACTIVITIES

A 4000 year old corpse preserved in ice.

Why hasnt it decomposed?

Why is carbon important?Carbon is the main constituent of all living cells (biochemistry, organic chemistry)Carbon can form long chained-molecules which are the basis for fats, carbohydrates, nucleic acids (DNA and RNA) and proteins.Component of fuel (coal and gas)Use in nanotubes for computers

AQA Science Nelson Thornes Ltd 2006 *

AQA Science Nelson Thornes Ltd 2006 *

Respiration, burning and decayExcrement and deathDecay (micro-organisms and bacteria)Respiration

The Carbon CyclePlants take in CO2 because they need carbon and oxygen to use in Through photosynthesis plants makeand other substances e.g. protein When animals eat plants they use some of the carbon containing compounds to grow Some carbon-containing compounds are used to release energy byphotosynthesis glucose (carbohydrate)respiration.

AQA Science Nelson Thornes Ltd 2006 *

AQA Science Nelson Thornes Ltd 2006 *

SUCCESS CRITERIAREMEMBER THAT CARBON CYCLE INVOLVES MANY PROCESES.TWO WAYS CARBON DIOXIDE LEAVES ATMOSPHEREFOUR WAYS CARBON DIOXIDE ENTERS THE ATMOSPHERE

MAIN Complete worksheet 1 and 2 on water and carbon cycle.

The carbon cycle True or false?

AQA Science Nelson Thornes Ltd 2006 *Green plants use carbon dioxide in photosynthesis.True

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AQA Science Nelson Thornes Ltd 2006 *Combustion removes carbon dioxide from the atmosphereFalse combustion releases carbon dioxide gas

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AQA Science Nelson Thornes Ltd 2006 *The largest store of carbon is the atmosphereFalse more is found in marine organisms and limestone rock deposits

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AQA Science Nelson Thornes Ltd 2006 *Respiration adds carbon dioxide to the atmosphereTrue

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AQA Science Nelson Thornes Ltd 2006 *Respiration only occurs in animalsFalse both animals and plants respire

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Decomposers remove carbon dioxide from the atmosphereFalse they respire and release carbon dioxide

AQA Science Nelson Thornes Ltd 2006 *Fossil fuels represent a huge (but decreasing) store of carbonTrue

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AQA Science Nelson Thornes Ltd 2006 *Increasing carbon dioxide may cause global coolingFalse scientists think it will cause global warming

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AQA Science Nelson Thornes Ltd 2006 *Energy is transferred from plants to animals to decomposersTrue

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AQA Science Nelson Thornes Ltd 2006 *Respiration releases energy to the environment in the form of heatTrue

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Plenary:

To be able to describe the carbon cycle and the processes related to it.To be able to describe the effect of human activities and global warming.

What is the Carbon Cycle?

The carbon cycle describes the movement of carbon through the environment. Carbon exists in the ground, in the sea, in plants and animals, and in the air.

Carbon moves through the processes shown in the picture below.

The natural processes shown in the picture above can release carbon dioxide into the atmosphere (shown by red arrows) by combustion, decay and respiration, or remove carbon dioxide from the atmosphere (shown by blue arrows) by dissolving in the sea (see below) and by photosynthesis, or "lock up" carbon in the ground (shown by green arrows) as a fossil fuel or by forming carbonate rocks.

Key word bingorespirationphotosynthesisdecayburningpotatocombustiondeforestationdissolvedLight intensitytreeschloroplastsglucosexylemleaf

**Photosynthesis during the day

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