C7 - 21st Century Science

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Bonds

Endothermic - energy taken in to form bond, positive reaction equation

Exothermic - energy given out to form bond, negative reaction equation

Reaction equation = energy required - energy released

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New Product Testing

1) Test potential catalysts

2) Create computer modle of which substances may work 

3) Designing and refining, must have safe mass production, high efficiency and be cost efficient

4) Risks to the enviroment must be assesed 

5) Monitore the quality, purity and efficiency 

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Producing Chemicals

RAW MATERIALS 

Convert raw materila to feedstock 

Feedstock are the actual reactants

SYNTHESIS

Convert reactants into the product 

Sensible rate of reaction

PRODUCTS SEPERATED

By products and waste disposed of and dealt with

PURITY IS MONITORED

Different acceptabilty depending on use

Medicine - very pure

Amonia - not very pure

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Haber Process

N2(g) + 3H2(g) Equilibrium symbol (http://www.bbc.co.uk/schools/gcsebitesize/science/images/gcsechem_equilibrium.gif) 2NH3(g)

1) Feedstock nitrogen - from air 78%

                       hydrogen - cracking chemicals waste product

2) Reversba;e, not all converted to helium but stays in vessel until equillibrium is reached

3) Used for ammonia and fertilisers

PRESSURE : 200 atmosphere

TEMPURATURE : 450

CATALYST : Iron 


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Haber Compromise

Forward reaction - exothermic so when tempurature increase to much the reaction wants to lower the tempurature and favours the backward reactio which is endothermic and takes in heat - percentage yeaild is decrease

Backward reaction - endothermic but if the tempurature is too low then the rate of reaction and speed of reaction will be too slow and uneconomical

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Haber Continued

Nitrogen fixation - turns unreactive nitrogen in air to useful compounds

Iron catalyst - bacteria 

                     chemists use it to mimick biological enzymes to

                     help it work at a economical tempurature and pressure

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Comparison

Alcohol boiling tempurature : 78

Alcohol melting tempurature : -114

Alcohol density : 0.79

SOLUABLE CHEMICALS 

Water boiling tempurature : 100

Water melting tempurature :0

Water density : 1

Alkane boiling tempurature : -89

Alkane melting tempurature: -183

Alkane density : 0.546

VOLATILE CHEMICALS

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Fermentation

Uses yeast - zymase

Sugar - - - gives- - - ethanol and carbon dioxide

Tempurature : 30

pH : 4

Fermentation stops at 20% as yeast denaturises


Must prevent oxygen from reacting or turns to vinegar

ethanol + oxygen - - - gives - - - ethanoic acid 

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Alcohol in Industry

Solvent : dissolves compunds + organic chemicals

Fragrances : mix oils and water to perfect as produces the smell and bulk chemicals

Meths : cleans brushes + acts as fuels 

Sodium + alcohol - - - gives - - - sodium ethoxide + hydrogen

Sodium + water - - - gives - - - sodium hydroxide + hydrogen

Alkanes do not react with sodium

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Alkanes

Hydrocarbons with strong C-C bonds

Saturated hydrocarbons

Burn in air to produce carbon dioxide and water

Cn H2n+2

Methane 

Ethane 

Propane 

Butane

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Alcohol

Cn H2n+2 OH

OH functional group

Ethanol - solvents and feuls

Methanol - chemical feedback and cosmetic manufacturing

Ethanol - CH4OH

Methanol - C2H6OH

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Distilation

1) ethanol is heated and vapour rises

2) passes through fractionalising column wich slows down particualy volatile chemicals

3) condenses and passes through cold condensing column to its purist form

THIS SEPRATES THE WATER FROM THE ALCOHOL AS IT HAS A LOWER BOILING POINT 

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Biomass Ethanol Production

MAde from left over crops 

Cellulose can sometimes stop the fermentation

So ecoli is modified to convert euaste and ethanol

TEMPURATURE : 35

pH : 6

Very sustainanble because no crops have to be frown for the proccess it recycles other crops

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Large scale ethanol

High quality + continous + quick/fast

1) Ethane from crude oil and gas is split from athene

Ethane - - - gives - - - ethene + hydrogen

2) Ethene reacts with steam and produces ethanol 

TEMPURATURE : 300

ATMOSPHERE : 70

CATYLYST : Phosphoric acid

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Carboxylic acid

 FUNCTIONAL GROUP : -COOH

Weak acids

Higher pH when dillute

Less reactive

Carboxylic acid + metal - - - gives - - - salt + hydrogen

Carboxylic acid + carbonate - - - gives - - - salt + water + hydrogen

Carboxylic acid + alkalis - - - gives - - - salt + water 

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Carboxylic acid smells

Long chained hydrocarbons = fatty acids

Strong odure and taste 

When ethanol is oxydised create vinegar

USEFUL - vinegar is produced, for food 

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Esters

FUNCTIONAL GROUP : COO

Esterfication - forming alcohol and carboxylic acid requires a strong catalyst

Manufacturing - perfumes, volitile nature is perfect 

                       flavourings and solvents

                       plasticisers make plastic more flexible

                      glycerol is a fatty acid

Animal - store energy as fats 

            saturated chains, solid at room tempurature, C double bond C

            unsaturated chains, liquid at room tempurature, C single bond C

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Making ester

REFLUXING

make ethanote by ethanol + ethanoic acid

DISTILLATION 

Fractionating column seperate esters 

PURIFICATION

Shaken with sodium carbonate to remove acidic impurities

Concentrated calcium chloride removes thanol

DRYING

Anhydrous calcium chloride absorbs water

ETHYL ETHANOATE

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Chemical analysis

Always analyse just a small sample 

- too much volume is hard to analyse

- keep for other tests

- if it goes wrong you need to keep some of the sample

Aquesous : solvent in water

Non aqueous : other than water

Standard procedure 

- make it safe and remove danger

- accurate

- reliable 

-controlled within company, national and international 

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Chromotography

Mobile phase                  and                    Stationary phase

1) Componants seperated and move back and forward between different phases

2) Different chemicals seperate at different points 

DYNAMIC EQUILIBRIUM

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Paper chromatography

Mobile : solvent

Stationary : filter paper

1) solvent movers up paper

2) sample siddolves and before it reaches the top the paper, depending on how soluable and attracked to paper the sample is

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Thin layer chromatography

Retension factor = distance be solute / distance by solvent 

SRM : standard reference material

Cromotography locating agent show colours of the chemicals

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Gas chromatography

Mobile : unreactive gas 

Stationary : viscous liquid

1) mixture coats the tube

2) different phases slow it down depending on how long each chemical stays in each phase so comes out in staggered sets

3) retension times are unique 

Chromatogram

Peak - how much of each chemical

X axis - which chemicals are in the solute

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Concentration

Mass of solute / volume of solution

Standard concentration - fill flask to 250cm cubed measure from the bottom of the meiscous 

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