Edexcel - Chemistry Unit 2 - 4 June 2013

the angle B-A-B is 180 so octraheral has bothe 90 and 180

Reduction can be defined as:
-gain of electrons
-loss of oxygen
or
- gain of hydrogen.

In this case, the hydrocarbon gains hydrogen, and so is reduced

Really helpful cheers!

Right sorry for all these questions:

When you react CH3I with alcoholic ammonia in a sealed tube, why is it that ethylamine (ch3ch2nh2) can't form but dimethylamine ( (CH3)2NH ) can form? I thought amines had a NH2 at the end so don't get dimethylamine


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Really helpful cheers!

Right sorry for all these questions:

When you react CH3I with alcoholic ammonia in a sealed tube, why is it that ethylamine (ch3ch2nh2) can't form but dimethylamine ( (CH3)2NH ) can form? I thought amines had a NH2 at the end so don't get dimethylamine


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Just did the Jan 13 paper and got 74/80, so that's 114 ums according to the UMS converter.

) Concentrated sulfuric acid is added to potassium chloride in a test tube. Steamy
fumes are given off which react with ammonia to give dense white smoke.
(i) Name the gas given off in this reaction.

Why is it HCl? I thought this is only for PCl5

) Concentrated sulfuric acid is added to potassium chloride in a test tube. Steamy
fumes are given off which react with ammonia to give dense white smoke.
(i) Name the gas given off in this reaction.

Why is it HCl? I thought this is only for PCl5

Just did the Jan 13 paper and got 74/80, so that's 114 ums according to the UMS converter.

No you need to remeber your Halide reactions with Sulfuric Acid. Sulfuric Acid is a relativly strong oxidising agent. So KF and KCl will react once, KBr two reactions and KI 3 reactions.

hi, how did you do q 21 b i and ii? I don't really understand. thanks

The chlorine questions?

21bi. You should know that disproportionation is where one species is both oxidised and reduced. Then you just have to work out the oxidation numbers of the chlorine.
Cl2: oxidation number is 0 because there is only one species in the molecule, so they would share the electrons equally
HCl: oxidation number is -1, because the halogens usually have an oxidation state of -1, and hydrogen is +1 so the Cl needs to balance this out
HClO: oxidation state of +1 because O is -2 (unless it's a peroxide or F2O), and H is +1, so Cl has to be +1 to balance it out.

bii. Le Chatelier's Principle; the change in equilibrium will counteract the change in concentration. Therefore the equilibrium will shift to the left, to reduce the concentration of HCl.

Ethylamine can't form because there is no CH2 in iodomethane.

Dimethylamine can form because the amine formed in the first reaction (CH3NH2) can act as a nucleophile:

CH3I + NH3 --> CH3NH2 + HI

CH3NH2 + CH3I --> (CH3)2NH + HI

Here's the chemguide page: http://www.chemguide.co.uk/mechanisms/nucsub/amines.html#top

do i have to remember the actual equations - including state symbols?

Just did the Jan 13 paper and got 74/80, so that's 114 ums according to the UMS converter.

How do you know what to draw here?


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yeah i mean what solution goes in what apparatus in the titration

How do you know what to draw here?


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