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AQA CHEM4 - 13th June 2012

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Reply 40

thegodofgod

Original post by Doctor.

I hope you're joking, I do find it interesting but it's too annoying when I don't get the right answer :frown:

. then it's just down right stupid, but when I do... :biggrin:

I don't joke :hat2:

Spoiler

What's best is having a starting compound and an ending compound and working out the route +/- conditions :woo:

Reply 41

Doctor.

Original post by thegodofgod

I don't joke :hat2:

Spoiler

What's best is having a starting compound and an ending compound and working out the route +/- conditions :woo:

I don't mind if they give me the starting compound I guess, I just need practice but I cant find enough questions! :frown:

Reply 42

thegodofgod

Original post by Doctor.

I don't mind if they give me the starting compound I guess, I just need practice but I cant find enough questions! :frown:

Just make up questions, e.g.

Ethanol --> Phenylethanone :smile:

Give names of organic mechanisms for forming the intermediate species as well.

(edited 12 years ago)

Reply 43

Doctor.

Original post by thegodofgod

Just make up questions, e.g.

Ethanol --> Phenylethanone :smile:

Give names of organic mechanisms for forming the intermediate species as well.

I will try, tomorrow is my chemistry day so :biggrin:

hopefully I will get the hang of it...Really wish there were some kind of questions though. I feel a little...as if I am cheating if I am making the questions myself :lol:

Reply 44

Glacier

Original post by thegodofgod

Just make up questions, e.g.

Ethanol --> Phenylethanone :smile:

Give names of organic mechanisms for forming the intermediate species as well.

That one looks quite difficult:

•

Ethanol (C₂H₅OH) --> Ethene (C₂H₄) (Dehydration with conc H₂SO₄)

•

Ethene (C₂H₄) + AlCl₃ + HCl + --> CH₃CH₂⁺ + AlCl₄^- (Electrophilic addition of HCl)

•

CH₃CH₂⁺ + Benzene (C₆H₆) + AlCl₄^- --> Ethylbenzene (C₆H₅CH₂CH₃) +AlCl₃ + HCl (Electrophilic substitution, AlCl₃ and HCl are catalysts)

•

Ethyl benzene (C₆H₅CH₂CH₃) --> Styrene (C₆H₅CH=CH₂) (Dehydrogenation, Fe₂O₃ catalyst)

•

Styrene (C₆H₅CH=CH₂) --> 1-bromoethylbenzene (C₆H₅CHBrCH₃) (Electrophilic addition, HBr)

•

1-bromoethylbenzene (C₆H₅CHBrCH₃) --> 1-phenylethanol (C₆H₅CH(OH)CH₃) (Nucleophilic substitution, NaOH, cold, aqueous)

•

1-phenylethanol (C₆H₅CH(OH)CH₃) --> 1-phenylethanone (C₆H₅C(O)CH₃) (Oxidation, K₂Cr₂O₇/dil H₂SO₄)

There's probably an easier way. :redface:

Reply 45

mrshinyshoes

Original post by thegodofgod

I'm doing BIOL2, BIOL5, CHEM4, CHEM5 this summer :eek4:

Join the club :tongue:

Reply 46

mrshinyshoes

Original post by Doctor.

I will try, tomorrow is my chemistry day so :biggrin:

hopefully I will get the hang of it...Really wish there were some kind of questions though. I feel a little...as if I am cheating if I am making the questions myself :lol:

I wish i could even begin to think of questions to ask myself :frown:

Reply 47

Doctor.

Original post by mrshinyshoes

I wish i could even begin to think of questions to ask myself :frown:

ahah same same :frown:

Reply 48

thegodofgod

Original post by Glacier

That one looks quite difficult:

•

Ethanol (C₂H₅OH) --> Ethene (C₂H₄) (Dehydration with conc H₂SO₄)

•

Ethene (C₂H₄) + AlCl₃ + HCl + --> CH₃CH₂⁺ + AlCl₄^- (Electrophilic addition of HCl)

•

CH₃CH₂⁺ + Benzene (C₆H₆) + AlCl₄^- --> Ethylbenzene (C₆H₅CH₂CH₃) +AlCl₃ + HCl (Electrophilic substitution, AlCl₃ and HCl are catalysts)

•

Ethyl benzene (C₆H₅CH₂CH₃) --> Styrene (C₆H₅CH=CH₂) (Dehydrogenation, Fe₂O₃ catalyst)

•

Styrene (C₆H₅CH=CH₂) --> 1-bromoethylbenzene (C₆H₅CHBrCH₃) (Electrophilic addition, HBr)

•

1-bromoethylbenzene (C₆H₅CHBrCH₃) --> 1-phenylethanol (C₆H₅CH(OH)CH₃) (Nucleophilic substitution, NaOH, cold, aqueous)

•

1-phenylethanol (C₆H₅CH(OH)CH₃) --> 1-phenylethanone (C₆H₅C(O)CH₃) (Oxidation, K₂Cr₂O₇/dil H₂SO₄)

There's probably an easier way. :redface:

Hmm - that's quite long-winded :tongue:

I'd go for:

Ethanol --> Ethanoic acid (Oxidation, heat/reflux, K₂Cr₂O₇ / H₂SO₄)

Ethanoic acid --> Ethanoyl chloride (SOCl₂ / PCl₅)

Ethanoyl chloride --> CH₃CO⁺ (CH₃COCl + AlCl₃ --> CH₃CO⁺ + AlCl₄^-)

CH₃CO⁺ --> C₆H₅COCH₃ (CH₃CO⁺ + C₆H₆ + AlCl₄^- --> C₆H₅COCH₃ + AlCl₃ + HCl).

Reply 49

Glacier

Original post by thegodofgod

Hmm - that's quite long-winded :tongue:

Hmm, I completely forgot about making acyl chlorides.

Here's another one:

Benzene --> N-(4-methylphenyl)propanamide (I did it in 4 steps)

Reply 50

thegodofgod

Original post by Glacier

Hmm, I completely forgot about making acyl chlorides.

Here's another one:

Benzene --> N-(4-methylphenyl)propanamide (I did it in 4 steps)

Benzene --> Methylbenzene (Friedel-Crafts Alkylation, Electrophilic Substitution, C₆H₆ + CH₃Cl + AlCl₃ --> C₆H₅CH₃ + AlCl₃ + HCl)

Methylbenzene --> 4-methylnitrobenzene (Electrophilic Substitution, H₂SO₄ + HNO₃ --> HSO₄^- + H₂O + NO₂⁺.
C₆H₅CH₃ + NO₂⁺ --> C₆H₄(CH₃)NO₂ + H₂SO₄ (H⁺ + HSO₄^-).

4-methylnitrobenzene --> 4-methylphenylamine (Reduction with Sn / HCl, C₆H₄(CH₃)NO₂ + 6[H] --> C₆H₄(CH₃)NH₂ + 2H₂O)

4-methylphenylamine --> N-(4-methylphenyl)propanamide (Condensation reaction, forming N-substituted amide from Carboxylic acid + Secondary amine --> N-substituted amide + Water
CH₃CH₂COOH + C₆H₄(CH₃)NH₂ --> C₆H₄(CH₃)NHCOCH₂CH₃ + H₂O)

(edited 12 years ago)

Reply 51

Picture~Perfect

I am not looking forward to this exam, Chemistry isn't exactly my best subject and there is so much you need to know for this. :frown:

Reply 52

Glacier

Original post by thegodofgod

I did the last step slightly differently, (acylation with CH₃CH₂COCl), but condensation should work as well.

What topics are you finding hardest? I don't understand proton nmr very well.

Reply 53

thegodofgod

Original post by Glacier

I did the last step slightly differently, (acylation with CH₃CH₂COCl), but condensation should work as well.

What topics are you finding hardest? I don't understand proton nmr very well.

Yeah, I thought of using an acyl chloride, but then with that white, misty HCl _(g) fumes are given off, which are poisonous - I was thinking of health + safety :tongue:

Very true - I do find structure determination (n.m.r.) very difficult :frown:

¹³C n.m.r. is not too bad though, as that's only carbon environments :colondollar:

Reply 54

Glacier

Original post by thegodofgod

Yeah, I thought of using an acyl chloride, but then with that white, misty HCl _(g) fumes are given off, which are poisonous - I was thinking of health + safety :tongue:

Very true - I do find structure determination (n.m.r.) very difficult :frown:

¹³C n.m.r. is not too bad though, as that's only carbon environments :colondollar:

Are you doing CHEM5 in June as well? I find that much harder (remembering transition metal and ligand stuff), and I really want an A* in chemistry. :frown:

I've got 7 A2 exams this summer as well (CHEM4, CHEM5, BIOL4, BIOL5, Physics PHA5C, Maths C4 and M2).

Reply 55

thegodofgod

Original post by Glacier

Are you doing CHEM5 in June as well? I find that much harder (remembering transition metal and ligand stuff), and I really want an A* in chemistry. :frown:

I've got 7 A2 exams this summer as well (CHEM4, CHEM5, BIOL4, BIOL5, Physics PHA5C, Maths C4 and M2).

Yeah, doing CHEM5 too - transition metals is more memory than anything else tbh :hmmm:

Ouch!

I have BIOL2, BIOL5, CHEM4, CHEM5, German 6GN03 (Speaking, 1/5/12), German 6GN04, Critical Thinking F502 ( :colone:

)

Just finished BIO6X (EMPA) this week, and got CHM6X after Easter hols :frown:

Reply 56

Glacier

Original post by thegodofgod

Yeah, doing CHEM5 too - transition metals is more memory than anything else tbh :hmmm:

Ouch!

I have BIOL2, BIOL5, CHEM4, CHEM5, German 6GN03 (Speaking, 1/5/12), German 6GN04, Critical Thinking F502 ( :colone:

)

Just finished BIO6X (EMPA) this week, and got CHM6X after Easter hols :frown:

Does everyone do EMPAs at the same time? My school does the ISA (6T instead of 6X), and every class does it on a different day, so everyone can find out the answers from the class that did it first. I did both Critical Thinking F501 and F502 in January and got a C. :frown:

I'm reapplying for medicine, so I hope they don't mind about that.

Anyway, to avoid to going off topic too much: are we expected to know all of the IUPAC priorities for naming functional groups? (Like how C₆H₅NO₂ is nitrobenzene, but C₆H₅NH₂ is phenylamine, not aminobenzene)

Reply 57

thegodofgod

Original post by Glacier

No - For BIO6X, the submission deadline is 15th May 2012 - so you can do it any time up until the day before. Probably the same for CHM6X as well.

Yeah - my set was the last to do the BIO6X written test :colone:

Unfortunately everyone in my year is doing the CHM6X (practicals + written test) at the same time :frown:

.

Our school does AS Critical Thinking over 2 years, i.e. F501 in June 2011 and F502 in June 2012 :smile:

Got a C (67 UMS) in F501, hoping to get at least (73/100 UMS) to get a B average :cool:

I'm reapplying for medicine as well next year :five:

The more we know the better, I suppose :tongue:

- I know my text book (A2 Nelson Thornes Chemistry for AQA) has a table which shows all of the prefixes and suffixes, but it doesn't explicitly say the priorities :s-smilie:

Reply 58

Bright.Inspiration.

Original post by Glacier

That one looks quite difficult:

•

Ethanol (C₂H₅OH) --> Ethene (C₂H₄) (Dehydration with conc H₂SO₄)

•

Ethene (C₂H₄) + AlCl₃ + HCl + --> CH₃CH₂⁺ + AlCl₄^- (Electrophilic addition of HCl)

•

CH₃CH₂⁺ + Benzene (C₆H₆) + AlCl₄^- --> Ethylbenzene (C₆H₅CH₂CH₃) +AlCl₃ + HCl (Electrophilic substitution, AlCl₃ and HCl are catalysts)

•

Ethyl benzene (C₆H₅CH₂CH₃) --> Styrene (C₆H₅CH=CH₂) (Dehydrogenation, Fe₂O₃ catalyst)

•

Styrene (C₆H₅CH=CH₂) --> 1-bromoethylbenzene (C₆H₅CHBrCH₃) (Electrophilic addition, HBr)

•

1-bromoethylbenzene (C₆H₅CHBrCH₃) --> 1-phenylethanol (C₆H₅CH(OH)CH₃) (Nucleophilic substitution, NaOH, cold, aqueous)

•

1-phenylethanol (C₆H₅CH(OH)CH₃) --> 1-phenylethanone (C₆H₅C(O)CH₃) (Oxidation, K₂Cr₂O₇/dil H₂SO₄)

There's probably an easier way. :redface:

Oh my word...

Reply 59

Glacier

Original post by Bright.Inspiration.

Oh my word...

I don't think the exam ever has organic synthesis questions with as many steps as that, and as thegodofgod pointed out, there is a much easier way to do that one.

I think it helps to remember common patterns, such as nucleophilic addition/substitution with C