OCR AS - Chemistry Unit F322 - Chains, energy and resource - REVISION!

Is there a thread of this kind going on for A2? :erm:

Reply 5

Original post by Joseppea

Here goes:

Define the term electrophile.

Crap book is crap. :tongue:

erm.. a positively charged species that is attracted to a negatively charged species. Or something like that. I'd probably write delta-positive/delta-negative in the exam.

Define the term isomer.

Reply 6

patra

2

Original post by Contrad!ction.

Crap book is crap. :tongue:

erm.. a positively charged species that is attracted to a negatively charged species. Or something like that. I'd probably write delta-positive/delta-negative in the exam.

Define the term isomer.

What do you mean by the book is crap...I feel the book has good information related to the course!

Reply 7

Original post by patra

What do you mean by the book is crap...I feel the book has good information related to the course!

Just don't rely on it. One of my Chemistry teachers avoids it like the plague whilst the other practically forces it upon us. Just so happens that the one who avoids it is pretty much the best teacher in the school - definitely one of them, anyway. It gives quite a lot of irrelevant stuff and I reckon it could be more succinct.

Saying that, considering I'm self teaching 3 further maths modules from the official OCR books, anything I don't understand gets pinned on how crap the book is so :redface:

...head of maths says the books are crap to make sure he keeps his job :tongue:

Reply 8

SteveCrain

Original post by Contrad!ction.

Just don't rely on it. One of my Chemistry teachers avoids it like the plague whilst the other practically forces it upon us. Just so happens that the one who avoids it is pretty much the best teacher in the school - definitely one of them, anyway. It gives quite a lot of irrelevant stuff and I reckon it could be more succinct.

Saying that, considering I'm self teaching 3 further maths modules from the official OCR books, anything I don't understand gets pinned on how crap the book is so :redface:

...head of maths says the books are crap to make sure he keeps his job :tongue:

By the book is best.

On the last exam, there were question you couldn't possibly know the answer to if you hadn't gone over the book.

What did everyone get in unit 1?

Also, I've a question.

Draw 2 repeat units of Poly(propene), from the polymerisation of
H3C---CH===CH2

Does it matter if you start your repeat units on the Carbon that has the methyl group, or is it the otherway round?

Reply 9

SteveCrain

Original post by patra

What do you mean by the book is crap...I feel the book has good information related to the course!

The book is the course

Reply 10

Original post by SteveCrain

By the book is best.

On the last exam, there were question you couldn't possibly know the answer to if you hadn't gone over the book.

Well, I didn't use the book. What question was this?

Original post by SteveCrain

Also, I've a question.

Draw 2 repeat units of Poly(propene), from the polymerisation of
H3C---CH===CH2

Does it matter if you start your repeat units on the Carbon that has the methyl group, or is it the otherway round?

I've been working through the same paper as you, it seems :tongue:

I did it as
.......H3C.....H.....H3C......H
------C-------C------C------C----
.......H.........H........H.......H

lol, crudeness... It shouldn't matter though, it's the same principle as drawing, say, 2-chloropentane - you could go from either end, have it 2 or 4 along.

It looks neater than my drawing though :tongue:

Reply 11

haha, here we go third time lucky :biggrin:

Original post by Contrad!ction.

Define the term isomer.

I believe the answer is 'a molecule with the same number of atoms but a different arrangement of atoms in space'

But it depends on whether or not its structural or stereo isomerism :tongue:

ok next question

what are primary, secondary and tertiary alcohols oxidised to? (state reactants and conditions)

(edited 13 years ago)

Reply 12

SteveCrain

Original post by Contrad!ction.

Well, I didn't use the book. What question was this?

I've been working through the same paper as you, it seems :tongue:

I did it as
.......H3C.....H.....H3C......H
------C-------C------C------C----
.......H.........H........H.......H

lol, crudeness... It shouldn't matter though, it's the same principle as drawing, say, 2-chloropentane - you could go from either end, have it 2 or 4 along.

It looks neater than my drawing though :tongue:

Yeh I did that; MS suggests otherwise, though. Probably doesn't matter.

And I can't remember the exact questions, there was one about uses of ammonia, and aside from that hte book explained everything other question on the exam.

Reply 13

Original post by SteveCrain

Yeh I did that; MS suggests otherwise, though. Probably doesn't matter.

And I can't remember the exact questions, there was one about uses of ammonia, and aside from that hte book explained everything other question on the exam.

For some reason, our head of Chem (who won't let me resit F321, grr) has only given us the papers, but not the mark scheme. >.<

I managed to answer everything but screwed myself over with that big cyclohexane question because I didn't take the q in properly and answered it all with silver nitrate stuff. I made some stupid mistakes in there as well, like forgetting that molecule shape.

viksta1000

what are primary, secondary and tertiary alcohols oxidised to? (state reactants and conditions)

Tertiary isn't. Primary alcohols are oxidised to aldehydes by distillation or carboxylic acids by reflux. Secondary alcohols are oxidised to ketones.

Describe briefly how fractional distillation can be used to convert crude oil into a small number of fractions [4]
Stolen from my teacher :tongue:

(edited 13 years ago)

Reply 14

Original post by viksta1000

what are primary, secondary and tertiary alcohols oxidised to? (state reactants and conditions)

Original post by Contrad!ction.

Tertiary isn't. Primary alcohols are oxidised to aldehydes by distillation or carboxylic acids by reflux. Secondary alcohols are oxidised to ketones.

oooh 2 / 3 mate :tongue:

lol

Reply 15

Original post by viksta1000

oooh 2 / 3 mate :tongue:

I've added a question now :tongue:

I know, I need to brush up on my conditions of reaction. Going through past papers, that's where I'm losing my marks.

I love how we're ignoring enthalpy/rates. Because they suck. :tongue:

Reply 16

Original post by Contrad!ction.

I've added a question now :tongue:

I know, I need to brush up on my conditions of reaction. Going through past papers, that's where I'm losing my marks.

I love how we're ignoring enthalpy/rates. Because they suck. :tongue:

Oi, don't go changing the subject, I expect you to get full marks on my question and nothing less before we progress onto another question :tongue:

lol....and yes they do suck :biggrin:

Original post by Contrad!ction.

Describe briefly how fractional distillation can be used to convert crude oil into a small number of fractions [4]
Stolen from my teacher :tongue:

difference sized fractions = different intermolecular bond strengths = different amount of energy needed to break bonds = different boiling points = different condensing points - so each fraction condenses at a difference point and hence seperation

I believe I've covered all the basics for full marks on that question, thank you very much :biggrin:

Describe two ways to make ethanol (state reactants and conditions)

(edited 13 years ago)

Reply 17

Original post by viksta1000

Oi, don't go changing the subject, I expect you to get full marks on my question and nothing less before we progress onto another question :tongue:

lol....and yes they do suck :biggrin:

No idea

Original post by viksta1000

difference sized fractions = different intermolecular bond strengths = different amount of energy needed to break bonds = different boiling points = different condensing points - so each fraction condenses at a difference point and hence seperation

I believe I've covered all the basics for full marks on that question, thank you very much :biggrin:

Didn't mention heating the crude oil :wink:

Original post by viksta1000

Describe two ways to make ethanol (state reactants and conditions)

Obsessed with alcohol are we? :tongue:

bleh, as soon as you talk about mechanisms, I'm screwed. I can do electrophilics and polymerisation and to a certain degree free radical, but other than that, I'm crap.

Reply 18