Organic and Physical Paper 2 Exam Questions Flashcards
The rate equation for a reaction is
Rate = k[E]
Explain qualitatively why doubling the temperature has a much greater effect on the rate of reaction than doubling the concentration of E
(3 marks)
Reaction occurs when molecules have energy greater than activation energy
Doubling T causes many more molecules to have this energy
Whereas doubling [E] only doubles the number with this energy
Suggest an environmental advantage of a condensation polymer compared to an addition polymer
Justify your answer
(3 marks)
Condensation polymer is biodegradable
Polar C=O group
Therefore can be attacks by nucleophile
Name a suitable method by which a mixture of amino acids formed by hydrolysis of a protein can be separated
Chromatography
Two solutions each of pH 4 and 9 are left open to the air
pH 9 solution changed more than the other solution
Suggest what substance might be present in air to cause the pH to change. Explain how and why the pH of the pH 9 solution changes
(3 marks )
CO2
pH decreases
Because acidic gas reacts with alkali/OH-
Consider this reaction:
2SO2(g) + O2(g) > 2SO3(g)
State the effect, if any, of using a smaller flask on the amount of sulfur trioxide at equilibrium
Explain your answer
(3 marks)
Increase
Decrease in volume causes an increase in pressure. Fewer molecules on RHS
Equilibrium shifts to oppose the increase in pressure
State how you could obtain a sample of alcohol from a reaction mixture
(2 marks)
Aqueous/ warn
Fractional distillation (chromatography allowed)
Suggest why initial rates of reaction are used to determine orders for the rate equation rather than rates of reaction at other times during the experiments
(1 mark)
Because the initial concentrations are known
How to distinguish between an actor chloride and a ketone?
Give reagents and observation with each compound
(3 marks)
Sodium hydrogen carbonate
Ketone - no change
Acyl chloride - fizzing or effervescence
