AS Chemistry- helping each other out!

Scroll to see replies

Hi there

The test for Halide Ions

The test solution, is made acidic with Nitric acid and then the silver nitrate solution.

The role of Nitric acid is the react with any carbonates to prevent the formation of the precipitate Ag2CO3, because this will mark the product (and you don't want that happening haha).

The equation:

2HNO3 + Na2CO3 --> 2NaNO3 + H2O + CO2

Fluorides: No precipitate will form.

Chlorides: White precipitate will form.
Ag+(aq) + Cl- --> AgCl(s)

Bromides: Cream precipitate will form.
Ag+(aq) + Br- --> AgBr(s)

Iodides: Pale yellow precipitate will form.
Ag+(aq) + I- --> AgI(s)

But you ask what happens if you add it after? Idk lol but maybe the carbonate will mask the product?

Hope that helps a little :bigsmile:

Thanks a lot :smile:

Reply 2181

Dinaa

Original post by Mamoona231

Thanks a lot :smile:

You're welcome :blushing:

Reply 2182

ozzie2

Original post by Dinaa

lol bruh

Ozzieeeeee, been ages :h:

Make sure you find out you got they questions wrong and if the mark scheme doesn't explain it properly, then ask here :smile:

Also, perhaps you should write down on a paper your mistakes?

Sup dina, how've you been?
Yeah it's mostly those bonding Q's with like vander vaals forces and **** because I sometimes get confused by them, also the typical careless errors.
I always write on my paper the answer and make a mental list of things I have to go over.

Reply 2183

Dinaa

Original post by ozzie2

wat exam board?

Reply 2184

frozo123

Just came across a unit 5 question which has questioned my knowledge a bit...

So when you're working out the number of moles for a gas at r.t.p, eg. hydrogen
are you working out the number of moles of H2 gas? or the number of moles for Hydrogen ( singular)

think it's the former but can someone confirm?

Reply 2185

C0balt

Original post by frozo123

H2

Posted from TSR Mobile

Reply 2186

_NMcC_

Original post by frozo123

Fundamentally: Hydrogen, Nitrogen, Oxygen and the Halogens all exist as diatomic molecules so yes, It's H2 (g) Although avogadro's constant can apply to anything from atoms to molecules to tin cans. 1 mole of anything is always 6.02 x 10^23 whatever.

Reply 2187

ozzie2

Original post by Dinaa

wat exam board?

AQA kiddo what about you?

Reply 2188

Bebo98

has anyone done the physics empa?

Reply 2189

Feraligatr

Original post by ozzie2

That feel when you get a B every past paper you do :frown:

It hurts but you can improve :smile:

Reply 2190

Feraligatr

I'm actually pissed off now. I've said this thousands of times now... :mad:

Original post by k.wills

ive done bio epma if anyone wants to swap for chemistry

Original post by Bebo98

has anyone done the physics empa?

This has been said billions of times across TSR and a few other people have said on this thread already, you're not allowed to provide answers for EMPA or ISAs AT ALL!
That would be classed as cheating which wouldn't be fair

You're not allowed to share answers at all or shared locked/unavailable papers.

You do realise that exam boards like AQA are monitoring TSR so if you get caught and are identified, there is a chance of you getting disqualified

YOU DO UNDERSTAND YOU'RE NOT ALLOWED CHEAT AND THAT COULD BE CLASSED AS CHEATING RIGHT?!!!!!!!!!!!!!!!!!!!!!!!! :angry:

(edited 8 years ago)

Reply 2191

ozzie2

Original post by Feraligatr

It hurts but you can improve :smile:

Yeah I mean a B isn't too bad considering I literally thought I knew nothing about chemistry, but after revising I feel more confident apart from the bloody intermolecular bonding and stuff which is just so annoying. If I can get near full marks in the section B part of the paper which I really like it will bump up my grade :smile:

Btw you done the chem empa paper? I would really like the answers :biggrin:

Spoiler

Reply 2192

kek6969

just started to revise properly for the chem empa tomorrow with the help of e rintoul, my anus is ready

Reply 2193

The Warsmith

Anyone here doing CEA chemistry?

Also my practical exam is THIS FRIDAY!!! :woo:

Reply 2194

Elocin505

Can anyone give me some hints on what the OCR chrmistry oxidation of alcohols coursework is like? ♥★ f323

Reply 2195

_NMcC_

To all recent

I've just joined recently but apparently AQA and other exam boards moderate these threads so we can't talk about practicals in detail. This is a high-profile thread so they'll probably check and maybe Identify you if you've given away too much info... Other regular users on this thread may have seen them?

Posted from TSR Mobile

(edited 8 years ago)

lol

Original post by Feraligatr

I'm actually pissed off now. I've said this thousands of times now... :mad:

YOU DO UNDERSTAND YOU'RE NOT ALLOWED CHEAT AND THAT COULD BE CLASSED AS CHEATING RIGHT?!!!!!!!!!!!!!!!!!!!!!!!! :angry:

Amen, will put a few words on my first post.

Original post by ozzie2

AQA kiddo what about you?

Edexcel 😃

Reply 2198

F1's Finest

People in the past have been caught by the exam boards for asking questions and in the rare case have had been noted down by the exam board. Remember that AQA etc moderate here so don't risk it :smile:

Reply 2199

Dinaa