[AnonyMatt]

(Original post by x_Melissa_x)
Alcohol + carboxylic acid

-Presence of conc. sulfuric acid
-Forms esters
-Often called 'esterification'



Elimination of alcohols

-Excess of conc. sulfuric acid
-180°C
-Elimination of a molecule of water
-Alkene formed



Oxidation of alcohols

-Aqueous potassium dichromate or aqueous sulfuric acid

All of that was amazing, thank you!

[x_Melissa_x]

(Original post by AnonyMatt)
All of that was amazing, thank you!

No problem



Ahhhhhhhhh, it's tomorrow!

[AnonyMatt]

(Original post by x_Melissa_x)
No problem



Ahhhhhhhhh, it's tomorrow!

I'm so happy I went to a chemistry lecture with my friend today. I came away with fantastic spider diagrams of NaOH as an organic reagent, and esters.
Also, past papers and mark schemes.

So, as my old chemistry teacher says, NaOH can wear 5 hats:

1) Aqueous, room temperature - acts as an alkali.
Reacts with acid to give salt + water.
e.g. NaOH(aq) + RCOOH -> RCOO-Na+ + H2O

2) Aqueous, heat under reflux
Reacts with R-Hal to give an alcohol
e.g. CH3CH2Cl + NaOH(aq) -> CH3CH2OH + NaCl

3) Aqueous, heat under reflux
Reacts with esters to give the sodium salt + Alcohol
e.g. RCOOR' + NaOH -> RCOO-Na+ + R'OH
NOTE: React further with HCl to gain the carboxylic acid + NaCl

4) Aqueous, heat under reflux
Reacts with amides to give the soldium salt + Amine
e.g. RCONHR' + NaOH -> RCOO-Na+ + R'NH2
NOTE: React further with HCl to gain the carboxylic acid + NaCl

5) THE PARTY HAT!
Because, it's in ethanolic solution.
Here it acts as a base. Reacts with R-Hal to give an alkene.
e.g. CH3CH2Br -> CH2=CH2 + HBr
Heat under reflux (90 degrees C)

That's all you need to know about NaOH for CH4 I think. I was surprised tbh because last year as far as I knew, we only needed to know about NaOH for CH5 I don't know if you've done any CH5 yet but the different forms of NaOH (like Na(OH)3) and stuff come up - I didn't really understand it tbh.

Stay on TSR btw, it'll be good to talk to someone who's doing CH5 too.
It was my favourite module tbh, I love the mathematical aspects of chemistry!

[x_Melissa_x]

Bring on the lurrrrvely U! So annoyed with myself! Got my timing completely wrong!

[Zebra-Zahra]

(Original post by x_Melissa_x)
Bring on the lurrrrvely U! So annoyed with myself! Got my timing completely wrong!

Argh, same here! I well and truly fu.ck.ed that up I did soooooo much work for it...what a fu.cking waste

Please excuse my language - I'm just so fed up, I can't even cry anymore

At least there was nobody in my school who found it remotely easy or even ok

[x_Melissa_x]

(Original post by Zebra-Zahra)
Argh, same here! I well and truly fu.ck.ed that up I did soooooo much work for it...what a fu.cking waste

Please excuse my language - I'm just so fed up, I can't even cry anymore

At least there was nobody in my school who found it remotely easy or even ok

I wish I could say something to make you feel better, but I guess I feel the same way as you do about it

[planetconwy1]

I am soooooo pleased i didnt bother revising for this exam. It was really tricky and the marks that will have got me through it were common sense ones

I mean the essay ones were easy, and at least the grade boundaries may lower.

[planetconwy1]

(Original post by AnonyMatt)
It was my favourite module tbh, I love the mathematical aspects of chemistry!

I KNOW! the maths part of chemistry have saved me so many times before now! They seem really easy for all the marks they give away for them too!

[welshboi10]

Hi i'm new here. Just took ch4 the other day, I thought it was all right! Section B was easier than section a for some reason. What questions did you struggle with?

[AnonyMatt]

I was iffy on lots of questions, because some I just didn't understand.

Unfortunately I ran out of time, and I never got to finish the last 6 mark question on question 5, the deduction of the mystery ester. I got it's molecular formula, the fact that there are double bonds, and there is a methyl group on the O, but I wrote something wrong for the NMR and I only drew the carboxyl group, 'cause I didn't quite figure out the R group in time.

Also at some point I said that going from alkanes -> aldehydes -> carboxylic acids was reduction, but realised on later questions that it wasn't, and made a mental note to go back and change it, but I forgot.

Also, I'm **** at mechanisms so I got the nitrobenzene one completely wrong, but I think I did good on the description of the mechanism of the nucleophilic addition of HCN.

Oh and I struggled on that question where we had to fill in the missing organic product and balance the equation! I have no idea if it's a set results we're supposed to know.

What I did was count the oxygens on one side, and on the other there were multiples of 3 or something, so I determined that there must be 2 moles of the CaCO3, then tried to think of an organic product that used the rest of the atoms... in the end I went for ethene (1 mole) and that would leave a molecule of water too...

[welshboi10]

Unlucky! Im almost didnt finish that last question on NMR, but luckily I just about had time. At least you put something down, you should get some marks for that. I also struggled with balancing that equation, and there's no special formula for doing it in the reveision guide. On the whole I think it went quite, I desperately need an A in it! What you think you got?

[AnonyMatt]

(Original post by welshboi10)
Unlucky! Im almost didnt finish that last question on NMR, but luckily I just about had time. At least you put something down, you should get some marks for that. I also struggled with balancing that equation, and there's no special formula for doing it in the reveision guide. On the whole I think it went quite, I desperately need an A in it! What you think you got?

I'm resitting - I got 82/120 last time. I need 43 marks for an A overall so I need to sit another paper.

If I got 105/120 I'll sit CH5 and try for an A*.

However, I'm thinking I got about 95/120 really.

Maybe 65/80. :/

[x_Melissa_x]

Lovely D!

In my school 36 people were entered for CH4 and the results were 1D, 2E, 33 U

[Sara_No_H!]

(Original post by x_Melissa_x)
Lovely D!

In my school 36 people were entered for CH4 and the results were 1D, 2E, 33 U

Me too! I think my dreams of medicine are over...

The story's the same in my school too - 44 people entered: 1C, 5D, 3E, 35U

I can't believe that my teachers had a real go at us, saying we were wasting their time, when their **** teaching was the reason why we had **** results!

[x_Melissa_x]

(Original post by rsp)
x

(Original post by kayla:))
x

(Original post by Emily164)
x

(Original post by AnonyMatt)
x

(Original post by welshboi10)
x

(Original post by planetconwy1)
x

How did you all do, if you don't mind me asking?

Sorry, I know I haven't quoted everyone in this thread - my computer won't let me

[Zebra-Zahra]

I had a D - 67/120

Not really sure how the rest of my class did, but I know that a LOT of people had Us

[AnonyMatt]

(Original post by x_Melissa_x)
Lovely D!

In my school 36 people were entered for CH4 and the results were 1D, 2E, 33 U

I got a C, 78/120.
That's worse than last year (I had 82), but I'm fairy sure it's wrong. I've applied for a photocopy of the script.

A friend of mine also sat the paper and got 104. We were pretty similar in our answers tbh, but there's almost a 30 mark difference so I think something is up!

Bit devastated though to be honest. I entered for CH5 anyway, as well as CH4 again, but hopefully I can withdraw that later.

[x_Melissa_x]

(Original post by AnonyMatt)
I got a C, 78/120.
That's worse than last year (I had 82), but I'm fairy sure it's wrong. I've applied for a photocopy of the script.

A friend of mine also sat the paper and got 104. We were pretty similar in our answers tbh, but there's almost a 30 mark difference so I think something is up!

Bit devastated though to be honest. I entered for CH5 anyway, as well as CH4 again, but hopefully I can withdraw that later.

I feel the same way about my stats exam! I had 83/100 but thought I'd done a lot better (90+) as I had almost all of the right answers when we went through the paper in class. My friend had similar answers to me but COMPLETELY missed about the last question (16 marks) and managed to get 98/100

[planetconwy1]

(Original post by x_Melissa_x)
How did you all do, if you don't mind me asking?

Sorry, I know I haven't quoted everyone in this thread - my computer won't let me

Well, a mixed bag of results really haha.

CH2, 96 a

CH4, 60 d

Im chuffed with CH2 because I only decided I was doing it an hour before the exam started haha.

[x_Melissa_x]

(Original post by planetconwy1)
Well, a mixed bag of results really haha.

CH2, 96 a

CH4, 60 d

Im chuffed with CH2 because I only decided I was doing it an hour before the exam started haha.

Congratulations on the A!

Oh, and welcome to the "I had a D in CH4" club - it seems to be the most popular grade on this thread