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Chemistry

A Level

How would you determine the pH of a solution?

pH is a measure of acidity and alkalinity. In fact, pH is a logarithmic scale from 0 to 14, with 0 being acidic and 14 being alkaline. When there is a high concentration of H⁺ ions then the sol...

Answered by • Chemistry tutor

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Predict the number of peaks in a carbon-13 NMR spectrum of the following carbonyl isomers of C5H8O. (i) CH3CH2CH2CH2CHO (ii) (CH3)3CCHO (iii) CH3COCH(CH3)2

(i) 5 peaks (ii) 3 peaks(iii) 4 peaks

Answered by Elizabeth D. • Chemistry tutor

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Describe how a buffer solution based on hydrochloric acid can act as a buffer. (5)

HCl ⇌ H++ Cl- (1)Added alkali: H⁺ reacts with added alkali/OH^-(1) Equilibrium shifts right forming Cl^- or H⁺(1) Added acid: Cl<...

Answered by Daisy R. • Chemistry tutor

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Explain what the rate-determining step in a reaction is with reference to activation energy.

The rate determining step is the slowest step in a multi-step reaction, and it is the step in the reaction with the highest activation energy. It is the step in the reaction which decides the overall rate...

Answered by Sammy A. • Chemistry tutor

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When propanal is reacted with potassium cyanide under weakly acidic conditions the resulting mixture does not rotate plane polarised light. Explain this observation.

A common mistake is to answer this question with the explanation that the light is not rotated because no optical isomers are present. However, this is incorrect. The only other time where plane polarised...

Answered by Sally D. • Chemistry tutor

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