organic chem 2 aqa higher (w/ pqs??? why)

what are the number of bonds an atom has determined by?

number of electrons in outer shell, e.g. C - 4 electrons/bonds

what are alcohols?

• homologous series - functional group is O-H

• general formula: Cn H2n+1 OH

• e.g. methanol, ethanol

• can be formed by hydration of an alkene, e.g. ethene + water → ethanol

what are the properties of alcohols?

• flammable - undergo complete combustion in air to produce CO2 and H2O

• react w/ sodium - one of the products is hydrogen

• first four alcohols dissolve completely in water to form neutral solutions

• can be oxidised by reacting w/ O2 (e.g. from the air) to form carboxylic acids

• (react w/ carboxylic acids to form esters + water)

what are the uses of alcohols?

• alcoholic drinks (usually ethanol used)

• solvents - (e.g. methylated spirit)

• fuels (e.g. ethanol is often used in spirit burners)

what is the name, formula and structure for the alcohol containing one C atom?

what is the name, formula and structure for the alcohol containing two C atoms?

what is the name, formula and structure for the alcohol containing three C atoms?

what is the name, formula and structure for the alcohol containing four C atoms?

what is fermentation?

• sugar → (w/ yeast) carbon dioxide + ethanol

• the ethanol produced is aqueous as the reaction is carried out in a solution

• the optimum temperature for this reaction is 37 degrees Celsius in a slightly acidic solution, in anaerobic conditions

what are carboxylic acids?

• homologous series - functional group is -COOH

• weak acids

• forned when an alcohol is reacted w/ an oxidising agent - e.g. ethanol + air OR potassium dichromate → ethanoic acid

• suffix is “-oic acid”

why are carboxylic acids weak in terms of ionisation and pH?

• do not ionise completely in water

• higher pH than aqueous solutions of strong acids of the same concentration

what is the name, chemical/structural formula and structure for the carboxylic acid containing one C atom?

structural formula: HCOOH

what is the name, chemical/structural formula and structure for the carboxylic acid containing two C atoms?

structural formula: CH₃COOH

what is the name, chemical/structural formula and structure for the carboxylic acid containing three C atoms?

structural formula: CH₃CH₂COOH

what is the name, chemical/structural formula and structure for the carboxylic acid containing four C atoms?

structural formula: CH₃CH₂CH₂COOH

how do carboxylic acids react with metal carbonates? provide an example of this

• (carboyxlic) acid + metal carbonate → salt + carbon dioxide + water

• react in the same way as any other acid!

• e.g. ethanoic acid + sodium carbonate → sodium ethanoate + carbon dioxide + water

how do carboxylic acids react with alcohols? provide an example of this

• alcohol + carboxylic acid (with acid catalyst) → ester + water

• (acid catalyst is often H₂SO₄)

• ethanoic acid + ethanol → ethyl ethanoate + water

what are esters? what are their typical properties?

• formed when a carboxylic acid and polymer (with an acid catalyst) react

• sweet smelling compounds - often used in sweets

• homologous - functional group is -COOC

• e.g. ethyl ethanoate

how do carboxylic acids dissolve in water?

dissolve in water to form acidic solutions with a pH of less than 7

how do carboxylic acids react with metals? provide an example of this

• metal + (carboxylic) acid → salt + hydrogen

• react in the same way as any other acid!

• e.g. aluminium + ethanoic acid → aluminium ethanoate + hydrogen

how do carboxylic acids react with bases? provide an example of this

• (carboxylic) acid + base → salt + water

• react in the same way as any other acid!

• e.g. ethanoic acid + sodium hydroxide → sodium ethanoate + water

what is addition polymerisation? what does the reaction require?

• when lots of small alkene monomers open up the double bonds to join and form polymers

• requires high pressure & a catalyst

what are the features of addition polymers? provide some examples

• addtion polymer contains the same type and number of atoms as the monomers that formed it because no other molecule is formed in the reaction

• have repeating units (four groups arranged around a main chain w/ 2 C atoms)

• e.g. ethene → poly(ethene), propene → poly(propene)

what is condensation polymerisation? give an example

• involves monomers which contain two functional groups

• produced from two different monomers w/ two of the same functional group on each monomer OR two monomers of the same type w/ two different functional groups on each monomer

• when the momomers react, they join and lose small molecules (usually water)

• e.g. ethanediol + hexanedioic acid → polyester + water

how is a polyester formed?

dicarboxylic acid + diol → polyester + water

how do you write the repeating pattern of this polyester?

name three differences between addition and condensation polymerisation

• addition - polymers produced from one monomer wheareas condensation - produced from two different monomers

• addition - polymers produced from ethene / alkene whereas condensation - polymers produced from diarboxylic acid and diol

• addition - polymer only product formed whereas condensation - small molecules such as water also

• addition - repeating unit is a hydrocarbon whereas condensation - repeating unit has an ester link and carbon chain

what is an amino acid? provide an example

how can they react?

• have two functional groups - amine group -NH₂ and carboxyl group -COOH

• e.g. glycine

• can react together in condensation polymerisation to form a polypeptide, a type of polyamine

how are polypeptides formed?

• condensation polymerisation reaction between two amino acids (acid group of one reacts with amine group of the other)

• water formed as a by product for every bond formed

• e.g. glycine → poly(glycine):

what is the difference between a polypeptide and a protein?

• polypeptides made up of chains of the same amino acid

• proteins made up of chains of different amino acids

give two reasons why proteins are important in the body

• enzymes - catalyse biological reactions

• haemoglobin - transports oxygen

name two polymers of sugars

• starch

• cellulose

what is a carbohydrate? provide 2 examples

• a biological molecule containing C,H and O

• e.g. starch and cellulose

what is DNA? what does it stand for?

• DNA - deoxyribonucleic acid

• large molecule essential for life

• encodes genetic instructions for development and functions of living organisms and viruses

describe the shape and structure of DNA

• most DNA molecules are 2 polymer chains, made from 4 different monomers called nucleotides

• double helix structure

• base pairs are A-T and C-G and form cross links holding the 2 nucleotide chains together

what does volatile mean?

evaporates easily