Paper 3 - Questions I Got Wrong

• The acids are of the form RCOOH • But in ethanoic acid R = CH3 • Whereas in ethanoic acid R = COOH • The unionised COOH group contains two very electronegative oxygen atoms • Therefore has a negative inductive (electron withdrawing) effect • The CH3 group has a positive inductive (electron pushing) effect • The O-H bond in ethanedioic acid is more polarised / H becomes more partially positive • More dissociation into H+ ions • Ethanedioic acid is stronger than ethanoic acid

• The cisplatin version only works as two chloride ions are displaced and the molecule joins on to the DNA • In doing this it stops the replication of cancerous cells

• By a ligand replacement reaction with DNA in which a dative covalent bond is formed between platinum and a nitrogen atom on guanine

• Can prevent the replication of healthy cells by bonding on to healthy DNA which may lead to unwanted side effects like hair loss • Unwanted side effects can be minimised by giving cisplatin in small doses

• Plot concentration against time • Take tangents at various times and find their gradient (this gives rate at different times) • Plot rate against concentration • First order would be a straight line through the origin