C1 Carbon Chemistry

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Atoms and molecules and compounds

Atoms are a type of particle so small you cant see them with a nucleus in the middle tiny particles called electrons move around the nucleus 

electrons are negatively charged 

-Atoms can join together to make molecules 

-Elements substance that only have one type of atom 

-A compund is a substance made up of different types od atoms 

Atoms are joined together by bonds :

electrons in an atom can make chemical bonds two types:

Covalent Bonds=share a pair of electrons

Ionic bonds=gives electrons to other atoms

electron becomes positively charged gets an electron becomes negatively charged charged attoms are called ions when negative and positive meet they can be attracted to form an ionic bond 

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Chemical formulas

Molecular formula tells us lots about atoms

Chemical equations show what happens in a reaction:

-chemicals react together to make new chemicals

-Chemicals that react are called reactants chemicals made are called the products 

-Scientists use equations to show these reactions

Equations:

reactants on the left and products on the right 

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Food additives

The additives make food last longer and essentialy the chemicals added improve the food 

there are four types:

food colours

flavour enhancers

antioxidants-react with oxygen in the air they go of but antioxidants stop the reaction

emulsifiers-oil and water seperate into two layers they help water and oil mix and not sperate 

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solutions

Solute-substance being dissolved 

Solvent-liquid its dissolving into

Solution-mixture of solute and solvent that doesnt seperate out 

Soluble-will dissolve

insoluble-not dissolve

Solubility-measure of how much it will dissolve 

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Paints and pigments

Pigments give paints their colours 

Binding medium a liquid that sticks to the pigment to the surface youve painted

Solvent makes paint easier to spread 

Paints are colloids:

A colloid is a mixture of really tiny particles mixed with another kind of stuff

they disperse not dissolve 

paint is a colloid whereby particles of the pigment are dispersed through a liquid 

Some paints are water based and some oil based:

emulsion = water based evapourates water then paint drys

oil paints = oil based dispersed in an oil then solvent dissolves oil 

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Special Pigments

Thermochromic pigments ---->change colour when heated

Can be used in fancy electric kettles that changes colour as the water boils 

Photophospherent pigments---->Glow in the dark

absorb light

store the energy

release light over a period of time

glow in the dark 

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Polymers

Polymers are long chains of molecules that are very large molecules formed when lots of small molecules(monomers)join together

this reaction is called polymerisation 

different types of polymerisation reaction:

-addition polymerisation=alkene monomers join together

polymerisation usually requires high pressure and a catalyst 

CATALYST =A chemical speeds up a reaction without being used up !!!!!!

Monomers are called=ethene 

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Polymers and their uses

Depends upon a polymers properties as to what it can be used for:

some are stronger and some are stretchier 

polyethene=light and stretchable used for a plastic carrier bag

Polymers used to make clothes:

Nylon is a polymer 

easily coated to make it waterproof 

tough lightweight and keep uv light out watervapour condenses sweat the vapour can then escape no condensation 

eg gore tex 

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Non biodegradable plastics

arent easy to get rid of 

they dont rot or decompose most polymers are non biodegradable 

we have to burry them in watse land

burn them or recycle them 

however their still sitting in landfill either way 

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Hydrocarbons - Alkenes

Hydrocarbons only contain hydrogen and carbon atoms 

Hydrocarbon is a compound formed from carbon and hydrogen atoms  only 

Alkenes are Hydrocarbons they are the simplest type you can get there just chains of carbon atoms joined together with hydrogen atoms all in an alkene are joined by single covalent bonds The four Alkenes are :

methane 

ethane

propane

butane 

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continued .....

Alkenes have double bonds 

Alkenes are hydrocarbons to 

they are different to alkanes because they have double covalent bonds 

two pairs of electrons are shared 

Bromine as a test for alkenes:

Bromin water is a bright orange solution that contains bromine

they react with double bonds

orange colours dissapear from the solution and bromine water is decolourised 

from orange to colourless 

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Fractional distillation of crude oil

Fossil fuels are finite 

coal oil and gas are all fossil fuels they are made from dead plants and animals burried from lillions of years ago 

they are non renewable fuels 

Finte=they will run out one day !!!!

Crude oil is sperated into different hydrocarbon fractions:

Crude oil is a mixture of different hydrocarbons

seperated by a process called fractional distillation

oil is heated turned into gas

gas enters a tall tower called fractionating colum 

column is hot and gradually gets cooler

near the bottom are the larger molecules 

hydrocarbons with lower boiling points leave the column near the top the smallest molecules 

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Packing

Cracking is splitting up long chain of hydrocarbons 

Cracking turns long alkane molecules into smaller alkane and alkene molecules so they are more useful 

Alkene molecules made by cracking can be used to make polymers or petrol 

Conditions for cracking include:

Hot 

Catalyst 

Cracking helps match supply and demand to proprtion out resources 

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Use of fossil fuels

Oil is very useful but can cause big problems 

Crude oil is found in the earths crust and pumped to the surface then transported but problems arise when its being transported 

ships that carry oil may crash and cause oil slicks 

this can kill sealife and increase pollution 

Choosing the best fuel:

Energy value

Availiability

Storage 

Cost

Toxicity 

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Burning fuels

Complete combustion happens when theres plenty of oxygen it releases lots of useful heat energy 

Complete combustion = hydrogen+oxygen--->carbon dioxide +water+energy

Incomplete combustion of hydrocarbons isnt safe as theres not enough oxygen and as a result produces carbon minoxide 

hydrocarbon+oxygen--->carbon monoxide+water+carbon+energy

carbon dioxide is a piosonous gas releasing less energy 

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Atmosphere

The atmosphere has changed as early earth was made from gasses that escaped from inside when volcanoes erupted

Probably earth was made up of carbon dioxide and steam

How is it now ......

greenplants a few billion years ago started to grow 

they removed carbon dioxide 

plants produced oxygen by photosythesis

photsythesis produced oxygen

combustion and respiration increase carbon dioxide and reduce oxygen 

78%nitrogen

21%oxygen

0.035%carbon dioxide

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Carbon cycle

Carbon cycled is constantly being recycled 

1)photsythesis by plants removes carbon dioxide from the air

2)respiration by plants/animals adds carbon dioxide to the air 

3)Combustion adds carbon dioxide to the air 

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Air pollution and acid rain

Burning fossil fuels releases sulfur dioxide and oxides of nitrogen

sulfur dioxide and oxides of nitrogen cause problems as acid rain kills plants and animals that live in lakes and rivers

also kills trees and damages limestone 

oxides of nitrogen causes a type of air pollution called photochemical smog 

Crbon monoxide is poisonous gas formed when petrol and diesel are generated  by cars

and it causes incomplete combustion

Air pollution makes life unhealthy and miserable 

can cause some ilnesses like asthma hard to cope with 

having a catalyst converter can reduce the amount of carbon monoxide cming out of exhausts 

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