Chemistry

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What is covalent bonding
- When atoms (nm) share pairs of electrons, they form covalent bonds. - These are very strong bonds between atoms. - Compounds with covalent bonds shown 3 ways: energy level diagram (like venn diagram, circles), dot-cross diagrams and stick diagram.
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Giant covalent structures: diamond and graphite
Very high melting and boiling points. Graphite - giant layers of covantly bonded carbon atoms,no bonds between layers,slide over each other, soft, slippery,conducts electricity,deolcalised electronsDiamond:rigid giant covalent structure, very hard.
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Fullerenes
Fullerene - form of carbon that can exist as large cage-like structures, based on hexagonal rings of carbon atoms. Used as a transport mechanism for drugs to specific sites of the body, as catalysts and as reinforcement for composite materials.
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Graphene
A single layer of graphite and so is just one atom thick. Excellenat electrical conductivity. In the future will help create new developments in the electronics industry.
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Metallic bonding
Positively charged metal ions,which are held together by electrons from the outermost shell of each metal atom. These delocalised electrons are free to move throughout the giant metallic lattice
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Giant metallic structures
Metals can be bent and shaped because of the layers of atoms in a giant metallic structure can slide over each other. Delocalised electrons in metals enable electricity and thermal energy to be transferred through a metal easily.
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Alloys
Alloys are harder than pure metals because the regular layers in a pure metal are distorted by atoms of different sizes in an alloy
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Fractional distillation
An effective way of separating liquids from a mixture of liquids by boiling off the substances at different temperatures, then condensing and collecting the liquids
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Chromatography
It separates mixtures of substances dissolved into a solvent as they move up a piece of chromatography paper. The different substances are separated because of their different solubilities in the solvent used.
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Crude oil
Crude oil is a mixture of many different compounds. Most of the compounds in crude oil are hydrocarbons - they contain only hydrogen and carbon atoms.
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Alkanes
Alkanes are saturated hydrocarbons. They contain as many hydrocarbons atoms as possible in their molecules. The general formula of an alkanes is: CnH(2n+2)
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Fractional distillation of oil
Crude oil is separated into fractions using fractional distillation. The properties of each fraction depend on the size of the hydrocarbon molecules in it. Lighter fractions make better fuels as they ignite more easily and burn well, clean flame
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Cracking
Large hydrocarbons molecules can be broken up into smaller molecules by passing the vapours over a hot catalyst, or by mixing them with steam and heating them to a very high temperature.
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Cracking 2
Cracking produced saturated hydrocarbons, used as fuels, and unsaturated hydrocarbons (alkenes).
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Other cards in this set

Card 2

Front

Very high melting and boiling points. Graphite - giant layers of covantly bonded carbon atoms,no bonds between layers,slide over each other, soft, slippery,conducts electricity,deolcalised electronsDiamond:rigid giant covalent structure, very hard.

Back

Giant covalent structures: diamond and graphite

Card 3

Front

Fullerene - form of carbon that can exist as large cage-like structures, based on hexagonal rings of carbon atoms. Used as a transport mechanism for drugs to specific sites of the body, as catalysts and as reinforcement for composite materials.

Back

Preview of the back of card 3

Card 4

Front

A single layer of graphite and so is just one atom thick. Excellenat electrical conductivity. In the future will help create new developments in the electronics industry.

Back

Preview of the back of card 4

Card 5

Front

Positively charged metal ions,which are held together by electrons from the outermost shell of each metal atom. These delocalised electrons are free to move throughout the giant metallic lattice

Back

Preview of the back of card 5
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