Synthesis

C2

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  • Created by: Belinda
  • Created on: 30-05-11 11:28

Balancing Equations & Carbon Compounds

Chemical Reactions = mass of reactant to the mass of the product

must be the same number of atoms on both sides of the equation

Carbon is an element found in group four (four electrons in its outer shell)
Has the ability to form four bonds with other atoms

Bonds on the carbon atoms remain free to join with other atoms to form carbon compounds

Carbon compounds are organic compounds = basis of life
E.g proteins, amino acids, carbohydrates, fats, fossil fuels, plastics these are called organic chemistry

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Alkanes & Alkenes

Alkanes (saturated hydrocarbons) = a hyrdrocarbon (Compound containing hydrogen and carbvon) They are join by single covalent carbon-carbon bonds.

A covalent bond is a strong bond when electrons are shared between non-metal atoms.
The maximum number of atoms are used so the hydrocarbon is saturated.
This is called an Alkane
Ethane Propane and Butane (3 simpliest alkanes)

Alkenes (unsaturated hydrocarbons) are joined by double covalent carbon-carbon bonds.
They are not bonded to the maximum number of atoms so are unsaturated hydrocarbons.
Ethen and propene (Simpliest alkenes)

'ene' (colourless) + Bromine water (yellow brown) > Colourless solution
'ane' (colourless) + Bromine water (yellow brown) > Yellow brown solution

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Cracking

= Breaking down long chain hydrocarbons

Short chain hydrocarbons release more energy when burned

Long chain hydrocarbons is heated until it vaporises

Vapour is passed over a heated catalyst, thermal decomposition Reaction takes place

When alkanes are cracked alkanes and alkenes are formed

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Monomers to polymers & Properties of Polymers

Polymers are long chain molecules formed from unsaturated monomers (Monomer = short chain hydrocarbon)

Monomers join polymers through condensatiuon reactions, these sometimes make plastics

Alkenes are unsaturated so are good at joining together without producing another substance (addition polymerisation)

Properties of polymers:
Good strength and elasticity, Don't corrode, Good electrical and thermal insulators, Low densities, Colourful, Easily moulded

Polymers can be divided into:
Thermo plastics, thermosets
Thermo plastics = easily softened and remoulded have weak inter molecular forces, not very rigid
Thermosets = can be softened, can't be resoftened and reshaped after first time heating

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Properties of plastics & Disposing plastics

Chemicals can be addded during manufacturing:

Plasticisers - make thermo plastics more flexible

UV and thermal stabilisers - prolong a plastics life

Cross linking agents encourage molecules to cross link, give more stable form of plastic

Disposing plastics is harmful to the environment these include:

Burning - air pollution, greenhouse affect, toxic fumes

Landfill sites - Non bio-degradable, waste builds up

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Product Development & Drug synthesis

Product development atom economy
Synthesis methods = knowledge of existing molecules ot predict new reactions

Computer modeling is used to predict shape, structure, properties and how toxic the substance will be by comparing to oter equations.
Any reaction with acid and a base always has the products salt and water

The production process (synthesis) Must produce the desired product in a reasonable quantity quickly and efficently

Scientists make sure processes they use give high atom economy for sustainable development as they provent waste
Not all reactions give a high yeaild or are efficent

Drug synthesis = Development of new medication
Before it was expensive and took many years, now computer stimulation technology makes the process more efficent

1. Tested on humans  2. tested on group of volunteers  3. toxicological study done on compound before compound

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Relative formula mass & Empirical formula

Relative formula mass = some of relative atomic mass of all its elements added together. You need to know formula of the compound and relative atomic mass of all atoms involved.

Empirical formula = always divide the data given by the relative atomic mass of the element then simplify ratio for the simpliest formula

To work out how much of a substance is used up or produced in a chemical reaction you have to write the equation, work out relatrive formula mass of each substance, check the totale mass of rectants = total mass of products then you need the ratio mass of first substance.

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Atom economy & Yeilds

chemical reactions produce more than one product but not all are useful

starting material (reactants) are converted into useful products most of the time

atom economy is a measure of the amounts of reactants that end up as useful products

Atom economy = (mass of atoms in useful product divided by total mass of atoms of product) x 100%

expected yeild = amount of product expected from a reaction (based on amount of reactants)

2 types of yeilds in a reaction: Theoretical yeild - calculated from masses of atom

Actual yeild - actual mass obtained from the reaction

Percentage yeild = (actual yeild / maximum theoretical yeild) x 100%

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Atom economy & Yeilds

chemical reactions produce more than one product but not all are useful

starting material (reactants) are converted into useful products most of the time

atom economy is a measure of the amounts of reactants that end up as useful products

Atom economy = (mass of atoms in useful product divided by total mass of atoms of product) x 100%

expected yeild = amount of product expected from a reaction (based on amount of reactants)

2 types of yeilds in a reaction: Theoretical yeild - calculated from masses of atom

Actual yeild - actual mass obtained from the reaction

Percentage yeild = (actual yeild / maximum theoretical yeild) x 100%

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Glossary

Mono unsaturated - an organic compound that only contains one double covalent carbon-carbon bond

Poly unsaturated - an organic compound with more than one double covalent carbon-carbon bond

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