Organic chemistry

Question 1

Crude oil

Answer 1

Finite resource found in rocks
Mixture of a very large number of compounds
Can be separated using physical methods including distillation
Hydrocarbons are most common. Most of these saturated (max bonds / only single) are alkanes

Question 2

Cracking alkenes

Answer 2

Catalytic cracking involves aluminum oxide catalyst. the long chain hydrocarbon is turned into a gas and then passed over a hot, powdered catalyst at temps of 550. the long chain splits as it passes over.
Steam cracking - Hydrocarbon turned to a gas then is mixed with steam. at high temps of 850 and under pressure the hydrocarbons will split into shorter hydrocarbon chains and and lots of small alkenes. The alkenes are then separated by fractional distillation.

Question 3

Alcohols reactions

Answer 3

They burn in air - producing carbon dioxide and water
Dissolve in water to form neutral solution (PH 7)
They react with oxidising agents to form carboxylic acids

Question 4

Alcohols uses

Answer 4

Methanol - Chemical feedstock
Ethanol - main alcohol used in alcoholic drinks
fuels

Question 5

Producing ethanol

Answer 5

Fermentation - of sugar, yeast using renewable resources,
Conditions - 35, anaerobic and heat enzyme catalyst
sugar -> ethanol + carbon dioxide

Question 6

Carboxylic acids

Answer 6

COOH - CH3COOH -C2H5COOH-C3H7COOH (CnHn+1COOH)
Reactions - dissolve in water to produce acidic solutions
- react with alcohols in the presence of an acid catalyst to produce esters
- they do not ionise completely with solutions, so do not release many H+ ions, making carboxylic acids weak acids meaning they have a higher PH (less acidic)

Question 7

Addition polymerisation

Answer 7

Alkenes can be used to make polymers such as pol(ethene) and poly(propene) by addition of polymerisation. In this reaction, many small molecules (monomers) join together to create large molecules (polymers)
- when drawing out polymer make sure to remember to draw bonds coming off the C’s out the brackets and little ‘n’ (meaning a large amount of these molecules joined together)

Question 7

Condensation polymerisation

Answer 7

When they react they join together, usually losing small molecules such as water, so reactions are called condensation reaction. simplest polymers are produced from two different monomers with two of the same functional groups on each other monomers.

Question 8

Amino acids

Answer 8

They have 2 different functional groups in a molecule. they react by condensation polymerisation to produce polypeptides. different amino acids can be combined in the same chain to produce proteins.

Question 9

DNA

Answer 9

this is a natural occurring polymer, most polymer

Question 10

What is a homologous series

Answer 10

Series of compounds with the same general formula, functional groups and similar chemical properties.

Question 11

Combustion of Hydrocarbons

Answer 11

-Exothermic reactions occurring when hydrocarbons are reacted with oxygen.
- complete combustion produced water and carbon dioxide
- incomplete combustion produced carbon or carbon monoxide and water

Question 12

How crude oil takes place

Answer 12

• Heated / vaporised
• vapour rises
• column is hotter at bottom and cooler at the top
• hydrocarbons cool as they go up due to different boiling points.

Question 13

Test for alkene

Answer 13

add bromine id colour changes from orange to colourless to orange it is an alkene if stays the same then alkane.