AS Haloalkane Reactions Sub/Elimination

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badeninc
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#1
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Help appreciated on the following questions:

1) Bromoethane can undergo further substitution. Write an overall equation for the reaction between bromoethane and bromine in which dibromomethane is formed. ( I know the reactions for chlorine not sure are they similar and I understand how to draw the mechanism)

2) CH3Br + 2NH3 ---) CH3NH2 + NH4Br
Name the organic product of this reaction (I presume it is an amine/amide)

3)Ethanenitrile can be made by reacting chloromethane with potassium cyanide:
i) write and equation for this reaction
ii) Name the mechanism for this reaction
iii) Explain in terms of bond enthalpies why bromoethane reacts faster than chloromehtane with potassium cyanide

4) chloromethane can react with ammonia to produce a primary amine:
i) what feature of the chloromethane molecule make it susceptible to attack by an ammonia molecule?
ii)Name the amine produced
iii) outline a mechanism for this reaction
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Katiee
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as chlorine and bromine undergo similar reactions so it wil lbe the same

2) amine

3) dont know sorry not in my spec..... actually ....

CH3Cl + CN- -------> ch3CN
dunno if thats right
i really should know doing A2 and all
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spook2575
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1) Br behaves exactly the same way as Cl so if you know the mechanism with Cl, just draw it out but replace Cl with Br

2)CH3NH2 is the organic compound

3i) CH3Cl + KCN ------> CH3CN + KCl
ii) Nucleophilic substitution
iii)br bond is longer and weaker than cl bond thus requires less energy to break

4i)
ii) CH3NH2 aminomethane
iii) nucleophilic substitution mechanism
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Kolya
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What are your thoughts on Q3 and Q4? I can help you understand if you say what your problem is, rather than just doing your homework for you.

Anyway, for Q3 you need to think about the formulae of the compounds: chloromethane is CH_3Cl and potassium cyanide is KCN . Do you know what the formula for ethanenitrile is (if not, can you work it out?) and thus write an equation for the reaction?
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spook2575
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(Original post by Lusus Naturae)
What are your thoughts on Q3 and Q4? I can help you understand if you say what your problem is, rather than just doing your homework for you.

Anyway, for Q3 you need to think about the formulae of the compounds: chloromethane is CH_3Cl and potassium cyanide is KCN . Do you know what the formula for ethanenitrile is (if not, can you work it out?) and thus write an equation for the reaction?
lol i did his homework for him since it aids my revision for unit 3 chem retake.
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badeninc
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Is it aminoethane or methylamine or are both the same?
I am prepared to learn at the same time so can take it step by step
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spook2575
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both exactly the same
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Kolya
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(Original post by badeninc)
Is it aminoethane or methylamine or are both the same?
I am prepared to learn at the same time so can take it step by step
Your "aminoethane" is normally called ethylamine and has the formula CH_3CH_2NH_2 - i.e. it is ethane with an amine group attached to one of the carbons. Methylamine is methane with an amine group attached to the (lone) carbon.
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spook2575
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sorry my bad, aminomethane.
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badeninc
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Is the main organic product when excess chlorine is added tetrachloromethane? and the reaction for multiple substitution from bromoethane to dibromoethane CH3Br+Br2----)CH2Br2 + HBR
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spook2575
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as far as im aware, that both makes sense.
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badeninc
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what about Ethanenitrile can be hydrolysed with carboxylic acid by heating it under reflux with a dilute acid. Identify the carboxylic acid? (Ethanoic Acid ?)
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mxgi
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(Original post by spook2575)
both exactly the same
They're totally different and not the same at all
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