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Chemistry

A Level

State the reagents and conditions for the formation of an aldehyde, starting from a primary-alcohol.

Answer: Heat with acidified potassium dichromate (IV), distilling off the aldehyde as it forms.
Explanation: To form an aldehyde from an alcohol the alcohol group must be oxidised. To do this we use ...

Answered by Tom O. • Chemistry tutor

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Use the concept of electronegativity to justify why the acid strengths of ethanedioic acid and ethanoic acid are different. (6 marks)

Stage 1: 1-2 marksFirstly, draw and explain the difference in structures between the two acids.
Stage 2: 3-4 marksThe unionised COOH groups in the ethanedioc acid contain two very el...

Answered by Lima H. • Chemistry tutor

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The reversible reaction 2 SO2 (g) + O2 (g) <-> 2 SO3 (g) has a delta H value of -197 kJ/mol. Use Le Chatelier's principle to explain what conditions would give the highest equilibrium yield and why industry uses different conditions. (5 marks)

Le Chatelier's principle states that if a system is disturbed - something changes - the system will tend to move in the direction that minimises the change. 3 marks from: The forw...

Answered by Conor C. • Chemistry tutor

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You are given a clear solution that is either an alkene or an alkane. Describe a test using bromine water that you could use to determine whether it is an alkene or alkane solution.

1 mark : Indication that the solution and bromine water should be mixed together1 mark : Indicating that the bromine water will de-colourise / go colourless if the solution contains an alkeneOR 1 mark awa...

Answered by Noah H. • Chemistry tutor

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Part a) Draw the mechanism of the attack of CN- on CH3COCH3 in the presence of HCN Part b) Explain why the product of this reaction does not rotate the plane of plane polarised light

Part a) 1 mark : Show the nucleophilic attack of CN- at the carbonyl forming the O-1 mark : Show the protonation of the O- via the deprotonation of HCNPart b)1 mark: Student has identified that the interm...

Answered by Noah H. • Chemistry tutor

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