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Chemistry

A Level

What are moles and how do you calculate them?

Well this depends whether you require the moles of gas, solid or solution as to which equation you use, moles relate the mass of the atom of interest to that of the number of atoms in 12 grams of carbon-1...

Answered by Benjamin T. • Chemistry tutor

1674 Views

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

1949 Views

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

3034 Views

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

1557 Views

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

1982 Views