organic chemistry

Question 1

catalytic cracking

Answer 1

-long chain molecules are passed over a heated catalyst and are broken down into shorter chain molecules

Question 2

isomers

Answer 2

hydrocarbons with the same molecular formula but different structural formulas

Question 3

monomers

Answer 3

unsaturated hydrocarbons (alkenes) joined together in polymerisation

Question 4

condensation polymerisation

Answer 4

the joining of 2 molecules with the elimination of a small molecule (usually water)

Question 5

polyesters

Answer 5

condensation polymers in which the monomers are joined by ester linkages (COO)

Question 6

polyamides

Answer 6

condensation polymers in which the monomers are joined by amide linkages (CONH)

Question 7

biodegradable and non-biodegradable polymers

Answer 7

• biodegradable polymers often contain ester/amide links which can be easily broken down by addition of water
• non-biodegradable polymers often consist of long chains of C and H atoms which have strong bonding between the atoms, making them resistant to breakdown by microorganisms or enzymes

Question 8

esterification

Answer 8

• alcohol + carboxylic acid -> ester + water

- conc sulphuric acid used as catalyst

Question 9

effect of branches on mp/bp

Answer 9

-branching in alkanes weakens intermolecular forces as they are more compact with less surface area -> lower mp/bp than straight chain molecules with the same Mr

Question 10

fractional distillation

Answer 10

the top of a fractionating column is where the hydrocarbon with the lowest bp fractions off

Question 11

as the length of the hydrocarbon chain increases:

Answer 11

• bp increases
• viscosity increases
• flammability decreases
• volatility decreases

Question 12

poly(alkene)

Answer 12

-polyalkenes no longer contain a C to C double bond because they have been broken to join more monomers