AQA CHEM4 - 13th June 2012

MEH I require more Organic Synthesis questions :frown:

Anyone?

Reply 141

Original post by itspossible

Oh lol I saw on AQA its 20% for each A2, and then 23.3% for CHEM2... might not have read it right though :wink:

Not a clue but I did CHEM1, CHEM2, CHEM5 and CHEM3 (ISA). So I only got CHEM4 & 6 to do. It's like 25 or something lol :s-smilie:

Not a clue.

Just seen your other post, well done on the impressive chemistry results! :smile:

Reply 142

Original post by Doctor.

MEH I require more Organic Synthesis questions :frown:

Anyone?

I just made this one:

Benzene --> N-cyclohexylethanamide

I did it in 4 steps.

Reply 143

Original post by Glacier

I just made this one:

Benzene --> N-cyclohexylethanamide

I did it in 4 steps.

You're awesome :h:

I shall do this as soon as I finish the questions I am doing :mad:

. Again THANKSSSS!!!

Reply 144

itspossible

Original post by Doctor.

Not a clue but I did CHEM1, CHEM2, CHEM5 and CHEM3 (ISA). So I only got CHEM4 & 6 to do. It's like 25 or something lol :s-smilie:

Not a clue.

Just seen your other post, well done on the impressive chemistry results! :smile:

Thanks!!

Reply 145

Original post by Glacier

I just made this one:

Benzene --> N-cyclohexylethanamide

I did it in 4 steps.

I think I've got it right, but please correct me if I'm wrong :smile:

Spoiler

Reply 146

Original post by Glacier

I just made this one:

Benzene --> N-cyclohexylethanamide

I did it in 4 steps.

I wasn't too sure what N-Cyclohexylethanamide looked like but I got it in 3 steps, seems wrong tbh :frown:

Spoiler

I don't know :frown:

Reply 147

Original post by thegodofgod

I think I've got it right, but please correct me if I'm wrong :smile:

Spoiler

Aw man, think I thought of the wrong compound lol

Reply 148

Original post by Doctor.

Aw man, think I thought of the wrong compound lol

I did that at first too and was proud that I managed to get it in 3 steps, but then realised that a phenyl ring isn't the same as a cyclohexyl ring :colondollar:

Reply 149

Original post by thegodofgod

I think I've got it right, but please correct me if I'm wrong :smile:

Spoiler

That should work, but I did it slightly differently, see below. :smile:

Original post by Doctor.

I wasn't too sure what N-Cyclohexylethanamide looked like but I got it in 3 steps, seems wrong tbh :frown:

Spoiler

I don't know :frown:

The first 2 steps are correct. I'll show my method below:

Spoiler

(edited 12 years ago)

Reply 150

Original post by Doctor.

To be honest, I think there is a way to get a good mark in each module.

CHEM1: It's tiny so revising the material isn't hard. Just master if they try to be a little...off topic (January 2012 paper lol).

CHEM2: Learn + Past Papers + make sure you can do all sorts of calculations! there are loads in CHEM2.

CHEM4: Not a clue, I am doing it right now!

CHEM5: STICK TO THE SPEC LIKE GLUE. The topics are so...synoptic. Just make sure you don't go learning random off spec stuff because it will not come up. The specification actually tells you exactly what will and will not be on the exam!

That's about it I guess :colondollar:

Hope it helps :h:

Thanks!

Quick question, just doing the Kinetics exam style questions in the textbook and am completely clueless as to how it comes to the following answer...

I get 0.25 not 75.23 (Excuse me if I'm being stupid!)

Screen shot 2012-04-12 at 18.51.41.png

Reply 151

Original post by skylight17

Okay.

Rate = k[C][D]².

Rearrange to find k:

k = Rate / [C][D]².

C = 0.15 moldm^-3, D = 0.24 moldm^-3. Rate = 0.65 moldm^-3s^-1.

k = 0.65 / [0.15][0.24]²

= 75.2314815...

k = 75.2 mol^-2dm⁶s^-1 (3 s.f.)

Reply 152

Original post by thegodofgod

I still get 0.2496 when I type in k = 0.65 / [0.15][0.24]² - what am I doing wrong?!!

I also don't know why this is 13? I get 5.2 x 10 (-3)
Screen shot 2012-04-12 at 19.08.44.png

(edited 12 years ago)

Reply 153

Original post by skylight17

I still get 0.2496 when I type in k = 0.65 / [0.15][0.24]² - what am I doing wrong?!!

I also don't know why this is 13? I get 5.2 x 10 (-3)
Screen shot 2012-04-12 at 19.08.44.png

Try typing in k = 0.65 / ([0.15][0.24]²).

Reply 154

Original post by Glacier

Try typing in k = 0.65 / ([0.15][0.24]²).

That worked! why do you have to do that with the brackets?...

ps: can you tell I don't do Maths :wink:

Reply 155

Original post by skylight17

I still get 0.2496 when I type in k = 0.65 / [0.15][0.24]² - what am I doing wrong?!!

I also don't know why this is 13? I get 5.2 x 10 (-3)
Screen shot 2012-04-12 at 19.08.44.png

Remember, what you're meant to type into the calculator is: (0.65) / (0.15 x 0.24²).

If you don't put the brackets in, it will do:
(0.65 / 0.15) x 0.24², which is 0.2496, which is what you're getting :tongue:

For the second one, try doing what I suggested above :wink:

Reply 156

Original post by thegodofgod

For the second one, try doing what I suggested above :wink:

I feel so stupid! haha

Cheers :biggrin:

Reply 157

mrshinyshoes

Original post by thegodofgod

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

I can beat that doing the whole of Chemistry again, Chem 1 down, 3 more to go :colone:

Reply 158

Original post by skylight17

That worked! why do you have to do that with the brackets?...

ps: can you tell I don't do Maths :wink:

The brackets are needed because k = 0.65 / [0.15] x [0.24]² is the same as k = 0.65 x [0.24]² / [0.15]. If it helps, maybe you should work out the denominator first ([0.15][0.24]² = 0.00864), then do 0.65 / 0.00864.

Reply 159