C1 Carbon Chemistry
- Created by: Eleanor200101
- Created on: 21-02-17 13:25
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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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