AQA CHEM2 ~ May 23rd 2012 ~ AS Chemistry

With the Sodium halide reactions with h2so4, have you all learnt the exact equations or do you just know what products form/colour changes and reduction/oxidation products in all of them?

And can someone enlighten me about how we distinguish between BaCl2 and MgCl2, are just supposed to know that BaSO4 forms a white ppt with sulfuric acid?

Reply 1183

Original post by puresse

what is the industrial production of ethene to ethanol? isit just the hydration of ethene with conc acid catalyst ( H2SO4 )

$C_2H_4 + H_2O \overset{Conc. H_2SO_4}{\rightarrow} C_2H_5OH$

Reply 1184

Xiomara

18

Do we need to know about slag? The NT book skips over it. Also, what is an alkylhydrogensulphate and do we need to know it? (working off the a level chemistry revision checklist here)

Reply 1185

Original post by stoppy123

Haha

is this your last exam?

Nope!
Maths D1 thursday morning and Geography in the afternoon. :shot:

Reply 1186

puresse

Original post by Mocking_bird

$C_2H_4 + H_2O \overset{Conc. H_2SO_4}{\rightarrow} C_2H_5OH$

thanks

Reply 1187

username890104

Original post by Mocking_bird

You didn't reply to my other post :frown:

Sorry, I was away from the laptop and when I came back I only read the most recent posts. I never really bother checking back because I'm arrogant like that and don't feel these fools could help me.

You know I'm joking, but let's see if someone is trigger happy on the -rep today.

And actually, you only really need to know that the continuous process is using crude oil and that the batch process is using carbohydrates. The advantages and disadvantages of each being whether fast or slow, non-renewable or renewable, pure or non-pure and inexpensive and expensive.

Edit: Someone took the bait. Too bad it has no impact on my reputation.

(edited 11 years ago)

Reply 1188

poopnoddy

Original post by Xiomara

Do we need to know about slag? The NT book skips over it. Also, what is an alkylhydrogensulphate and do we need to know it? (working off the a level chemistry revision checklist here)

The alkylhydrogen sulphate is whats formed when you hydrate an Alkene with h2so4 catalyst, but that alkylhydorgensulphate is what is formed before the alcohol ( i think )

Reply 1189

Original post by Xiomara

Do we need to know about slag? The NT book skips over it. Also, what is an alkylhydrogensulphate and do we need to know it? (working off the a level chemistry revision checklist here)

Alkylhydrogensulphate is what you get from the electrophilic addition with sulphuric acid.

You also need to know the hydrolysis reaction for alkylhydrogensulphate to make ethanol.

Reply 1190

username890104

Original post by Xiomara

Do we need to know about slag? The NT book skips over it. Also, what is an alkylhydrogensulphate and do we need to know it? (working off the a level chemistry revision checklist here)

No, we don't need to know about slag.

Reply 1191

Libby18

Original post by Mocking_bird

$C_2H_4 + H_2O \overset{Conc. H_2SO_4}{\rightarrow} C_2H_5OH$

what about phosphoric acid?

Reply 1192

stoppy123

4

Original post by Mocking_bird

Nope!
Maths D1 thursday morning and Geography in the afternoon. :shot:

Ahh, I've got this, and then 2 psychology exams :confused:

How'd you find the bio??

Reply 1193

Original post by Tullia

Sorry, I was away from the laptop and when I came back I only read the most recent posts. I never really bother checking back because I'm arrogant like that and don't feel these fools could help me.

You know I'm joking, but let's see if someone is trigger happy on the -rep today.

And actually, you only really need to know that the continuous process is using crude oil and that the batch process is using carbohydrates. The advantages and disadvantages of each being whether fast or slow, non-renewable or renewable, pure or non-pure and inexpensive and expensive.

Oh okay, so just for the fementation and direct hydration then?

The notes I had were on the extraction of metals stuff.
So we definitely dont need to know if its batch or continuous for each of those?

Reply 1194

Xiomara

18

Original post by poopnoddy

The alkylhydrogen sulphate is whats formed when you hydrate an Alkene with h2so4 catalyst, but that alkylhydorgensulphate is what is formed before the alcohol ( i think )

Original post by Mocking_bird

Alkylhydrogensulphate is what you get from the electrophilic addition with sulphuric acid.

You also need to know the hydrolysis reaction for alkylhydrogensulphate to make ethanol.

Oh, excellent. OK, I can do that reaction, just never named the intermediate :tongue:

Haha.

Original post by Tullia

No, we don't need to know about slag.

*happy dances*

Reply 1195

kings786

anyone got the mark scheme for the jan 2012 chem 2 exam?

Reply 1196

TaraBelle

10

Original post by Lauramayxxxx

So in this example...

TiCl4(g) + 4Na(I) ----> 4NaCl(s) + Ti(s)

The question says, what is the role of the sodium?
I got the answer right that it was a reducing agent, but is this because it's going from 0 to +1? Or is it due to it reducing titanium!? :s :boring:

Well both I think. It's been oxidised itself, and has reduced the titanium, meaning it's a reducing agent :smile:

Reply 1197

stoppy123

4

Original post by Lauramayxxxx

So in this example...

TiCl4(g) + 4Na(I) ----> 4NaCl(s) + Ti(s)

The question says, what is the role of the sodium?
I got the answer right that it was a reducing agent, but is this because it's going from 0 to +1? Or is it due to it reducing titanium!? :s :boring:

Reducing agent, is an electron donor.

That means, it's given it's electrons to the titanium, which has oxidised the titanium, as it has donated it's electrons, the Na has gone from 0 to +1

Reply 1198

jqian

1

Original post by Lauramayxxxx

So in this example...

TiCl4(g) + 4Na(I) ----> 4NaCl(s) + Ti(s)

The question says, what is the role of the sodium?
I got the answer right that it was a reducing agent, but is this because it's going from 0 to +1? Or is it due to it reducing titanium!? :s :boring:

Both of your statements are correct. The reducing agent gets oxidised (so the oxidation state before reaction goes up after the reaction), the other "thing" (i.e. the TiCl4) gets reduced as Ti's oxidation state is +4 before reaction and 0 after reaction.

Reply 1199