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Chemistry

A Level

A chemist has 3 beakers, each containing a pure sample of acetone (2-propanone), isopropanol (2-propanol) and propanal. Using chemical techniques, suggest how the chemist may be able to determine which beaker contains which sample. [4]

Brady's reagent is an orange solution of 2,4-dinitrophenylhydrazine which reacts with carbonyl containing functional groups to produce an orange precipitate (2,4-dinitrophenylhydrazone derivative of the c...

Answered by Stephen M. • Chemistry tutor

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State and explain the evidence for the delocalisation of electrons in benzene (6 marks)

Benzene does not decolourise bromine water, showing it does not undergo electrophilic addition reactions as the delocalised pi structure is very stable. All of the carbon-carbon bond lengths are the same;...

Answered by Romi A. • Chemistry tutor

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An unknown gas from a reaction is contained in a 2 litre beaker, at standard atmospheric pressure and a Temperature of 25 Celsius. Calculate the number of moles of the gas.

PV=nRT n=PV/RT=(1.01*10⁵0.002)/(8.31298)=0.0816 moles

Answered by James M. • Chemistry tutor

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Can you describe four variables which affect the rate of a chemical reaction and how they affect the rate?

Temperature: A higher temperature increases the rate of a reaction by increasing the number of particles with enough energy to take part in a reaction.
2) Particle size: The smaller the particl...

Answered by Steven S. • Chemistry tutor

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