crazelkp.blogg.se

It is the only step that matches the rate equation.Ģ An S N 1 reaction produces a primary carbocation which rearranges to form a tertiary carbocation before reacting with hydroxide ions tertiary carbocations are more stable than secondary carbocations.Įdexcel A2 Chemistry Answers to questions in Student Book page 33 1 a The larger E A, the larger the value of E A / RT and ln k becomes less positive that means that k gets smaller and so the rate of reaction gets smaller.Įdexcel A2 Chemistry Answers to questions in Student Book page 31 1 a b

2 The catalyst is used up but is then regenerated to be used over again.Įdexcel A2 Chemistry Answers to questions in Student Book page 29 1 aĪs T increases E A / RT decreases and ln k becomes more positive that means that k gets larger and so the reaction is faster. Įdexcel A2 Chemistry Answers to questions in Student Book page 27 1 Lead is adsorbed onto the metal catalyst and is not desorbed. After 8 days, 1/2 of the original amount remains after another 8 days, 1/4 remains and after 24 days the fraction remaining is 1/8. 2 I-131 decays in a first order process, so the half-life is constant and doesn’t depend on concentration. b You should get the same half-life each time – approximately 180 s. c 0.010 65 s–1 d In the rate-determining step, A splits up.Įdexcel A2 Chemistry Answers to questions in Student Book page 23 1 a Have an excess of methanoic acid. It would be hard to determine if the graph was truly a straight line from two points.Ī rate = k b The graph of rate versus concentration should be a straight line showing that it is first order. 2 a1 b2 c3 d Rate = k2 e 9.15 x 10–5 mol–2 dm6 s–1Įdexcel A2 Chemistry Answers to questions in Student Book page 19 1 If there is too much thiosulfate, the solution will not change colour, or will take a very long time to change. b The gas syringe little of the gas would collect in the measuring cylinder method.Įdexcel A2 Chemistry Answers to questions in Student Book page 15 1 The mixture will not change colour until all the thiosulfate has reacted with iodine. Hydrogen has a very low density there would be little change in the mass of the reaction vessel.Ī The gas syringe. 2Ī Collect the hydrogen in a gas syringe. b Warm the mixture but not too much (about 35 ☌). Edexcel A2 Chemistry Answers to questions in Student Book page 13 1 a Put the milk in a fridge.