**Chemistry...Before/After

reznov

Hermione Granger wrote: »

Here's hoping for a lovely leaving cert chemistry paper in 2012 in approx 1 hour 48 minutes time with water of crystallistaion preparation of ethene and ethyne and volatile liquid

SEC needs to make it up to us for removing Sodium Dichromate.
:pac:

Pepperr

Thanks for all the tips and info guys, best of luck to all of you! Heading in now, light a candle for me

Hayezer

For the big crude oil fractioning process do we need to know all the different fractions and boiling points ?

leaveiton

Hayezer wrote: »

For the big crude oil fractioning process do we need to know all the different fractions and boiling points ?

Don't think you need to know the fractions, you definitely don't need to know the boiling points anyway!

Hermione Granger

Quick question why is dichromate in the pear shaped flask in ethanoic acid and not in ethanal?

Thanks in advance

DepoProvera

leaveiton wrote: »

Don't think you need to know the fractions, you definitely don't need to know the boiling points anyway!

Well you need to know like gas, light gasoline, naphtha, heavy and gas oil, residue and a few uses for each...

leaveiton

DepoProvera wrote: »

Well you need to know like gas, light gasoline, naphtha, heavy and gas oil, residue and a few uses for each...

Yeah but you don't need to know them in order of like what comes off first and that. Obviously you need to know what they are and their uses.

leaveiton

Hermione Granger wrote: »

Quick question why is dichromate in the pear shaped flask in ethanoic acid and not in ethanal?

Thanks in advance

My book has it in a pear flask in both

DepoProvera

leaveiton wrote: »

Yeah but you don't need to know them in order of like what comes off first and that. Obviously you need to know what they are and their uses.

I think they asked once about a fraction with a specific carbon chain length before..

reznov

Hermione Granger wrote: »

Quick question why is dichromate in the pear shaped flask in ethanoic acid and not in ethanal?

Thanks in advance

Because in the prep of ethanal we do not want complete oxidation to Ethanoic.
Whereas in the Ethanoic acid prep, it ensures that we oxidise fully to CH3COOH.

Hermione Granger

DepoProvera wrote: »

I think they asked once about a fraction with a specific carbon chain length before..

It was along the lines of which of these has the longest carbon chain the answer was of course bitumen:rolleyes:

Spattersonox

leaveiton wrote: »

Yeah but you don't need to know them in order of like what comes off first and that. Obviously you need to know what they are and their uses.

Our teacher told us to know everything about fractional distillation. inside out, back to front

Cosmic.Postman

reznov wrote: »

Because in the prep of ethanal we do not want complete oxidation to Ethanoic.
Whereas in the Ethanoic acid prep, it ensures that we oxidise fully to CH3COOH.

That's why in the prep of ethanal you have ethanol in excess and in the prep of ethanoic acid you have the sodium dichromate in excess. Having the dichromate in the flask doesn't necessarily mean it'll oxidise the ethanol further to ethanoic acid, does it?

reznov

Spattersonox wrote: »

Our teacher told us to know everything about fractional distillation. inside out, back to front

What's fractional distillation?

reznov

Cosmic.Postman wrote: »

That's why in the prep of ethanal you have ethanol in excess and in the prep of ethanoic acid you have the sodium dichromate in excess. Having the dichromate in the flask doesn't necessarily mean it'll oxidise the ethanol further to ethanoic acid, does it?

That's what Declan Kennedy states in his book "Chemistry Alive". I'm just passing on his teaching.

Spattersonox

reznov wrote: »

What's fractional distillation?

that's how they split up crude oil you probably have another name for it

Hayezer

#sarcasm

reznov

Spattersonox wrote: »

that's how they split up crude oil you probably have another name for it

I was just kidding with you. :P You were talking about knowing everything back to front. ^^

Spattersonox

reznov wrote: »

I was just kidding with you. :P You were talking about knowing everything back to front. ^^

omg duh! sorry, these exams have robbed me of my wits :L i'm such an idiot

reznov

Spattersonox wrote: »

omg duh! sorry, these exams have robbed me of my wits :L i'm such an idiot

You're just on the look out. :cool:

Hayezer

Spattersonox wrote: »

omg duh! sorry, these exams have robbed me of my wits :L i'm such an idiot

It happens to the best of us!
Please be gentle Chemistry..

Spattersonox

http://www.youtube.com/watch?v=DMFg2aU3x4o Inspirational words from the weird guy in every single Adam Sandler film! haha

Hayezer

Good luck!

Rossie17

How was the paper? What experiments came up?

leemurta

Rossie17 wrote: »

How was the paper? What experiments came up?

It was alright, Ethene, Boiling point of a vol. liquid(finally a prediction came true) and a sodium carbonate titration were first three questions.

xcorina

That was just horrible.

Rossie17

leemurta wrote: »

It was alright, Ethene, Boiling point of a vol. liquid(finally a prediction came true) and a sodium carbonate titration were first three questions.

Wow they were out of the blue. What kind of questions came up in the rest of the paper?

TMCGY

Do able paper! Anyone else get a really wierd number for the volatile liquid calculation??

Gentlemanne

xcorina wrote: »

That was just horrible.

xcorina wrote: »

That was just horrible.

xcorina wrote: »

That was just horrible.

Wow, must have been 3 times as horrible as usual.

I didn't like it either. There was some nasty bits

SuchGold

TMCGY wrote: »

Do able paper! Anyone else get a really wierd number for the volatile liquid calculation??

Yeah I got like 53000 or something. Just realised its 101 kPa..