AS Chemistry- helping each other out!

Original post by samwillettsxxx

I know everything about reducing oxidation redox ect but for the ox. States if the number goes down is it reduced and if number goes up its oxidised
Just want a way that would save me thinking time?

Number is reduced, so species is reduced.
Number goes down, species is reduced(or goes down, so to speak)

So for oxidation numbers maybe just remember. Down, Down and Up, Up?

Idk I don't really have a mnemonic for that one to remember it by in any other way.

Reply 3322

Bhavika22

5

Original post by samwillettsxxx

I know everything about reducing oxidation redox ect but for the ox. States if the number goes down is it reduced and if number goes up its oxidised
Just want a way that would save me thinking time?

Try OILRIG! oxidation Is Loss Reduction Is Gain! Note, reduction doesn't mean go up though as gaining electrons which are negative pull you down however oxidation is where you give electrons up so positie

(edited 8 years ago)

Reply 3323

Original post by thymolphthalein

Number is reduced, so species is reduced.
Number goes down, species is reduced(or goes down, so to speak)

So for oxidation numbers maybe just remember. Down, Down and Up, Up?

Idk I don't really have a mnemonic for that one to remember it by in any other way.

Thanks so if it was 0 to -4 it's reduced
-5 to say 2 is oxidised?

Reply 3324

Original post by Bhavika22

Try OILRIG! oxidation Is Loss Reduction Is Gain! Note, reduction doesn't mean go up though as gaining electrons which are negative pull you down however oxidation is where you give electrons up so positie

Yeah I do use oil rig I know all that I mean just so I can identify if it's reduced or oxidised quickly by realising if the ox state goes down it's reduced and if the ox state goes up its oxidised
Thank u anyway :smile:

Reply 3325

Original post by samwillettsxxx

Thanks so if it was 0 to -4 it's reduced
-5 to say 2 is oxidised?

Yes exactly. :smile:

I would have said OILRIG (oxidation is loss of electrons, reduction is gain of electrons), but that is more specifically for the loss of electrons.

When you lose electrons, the charge will be postive.
When you gain electrons, the charge will be negative.

But you could have something go from +3 to +5 as well and it is will oxidized, so you can't always depend on it increasing from a negative to postive.

Reply 3326

Original post by thymolphthalein

Yes exactly. :smile:

I would have said OILRIG (oxidation is loss of electrons, reduction is gain of electrons), but that is more specifically for the loss of electrons.

When you lose electrons, the charge will be postive.
When you gain electrons, the charge will be negative.

But you could have something go from +3 to +5 as well and it is will oxidized, so you can't always depend on it increasing from a negative to postive.

Thank u for all the help :smile:

Reply 3327

I was just wondering if I've named this correctly?

Reply 3328

Original post by samwillettsxxx

I was just wondering if I've named this correctly?

Yep.

Reply 3329

Original post by thymolphthalein

Yep.

Thank u, I know so many questions I'm sorry but in elimination does the OH attack the hydrogen on the carbon to the left of the carbon attached to the halogen

Reply 3330

Original post by samwillettsxxx

Thank u, I know so many questions I'm sorry but in elimination does the OH attack the hydrogen on the carbon to the left of the carbon attached to the halogen

Wouldn't that be nucleophilic substituition, if it was a nucleophilic attack?

It would come from the side that the halogen is not on.

Elimination is when halogenoalkanes undergo a reaction with NaOH(or another alkali) to form an alkene, Sodium Halide and water.

Reply 3331

Cherry82

21

Guys please help me, I can't seem to name any thing. I can't name one single thing, I find it so hard to find a pattern with how to name so and so and now I'm going over esterification and esters. Naming things has been a nightmare, people have explained but I still don't get it.

Reply 3332

jontypickles

2

For naming esters, the way I do it is the is somthing-anoate is always the carboxylic acid with the something-anoic acid on the end because both the ends are weird. For the first part which is something-thyl, it will always be whatever else your reacting, for example, if you react propanoic acid and ethanol in the presence of an H2SO4 catalyst, the organic product will be ethyl (since ethanol is the other thing or alcohol) propanoate (because propanoic acid is the carboxylic acid).

Reply 3333

ilovereading

2

I would just like to declare in advanced that I am utterly ****ed for my Chemistry exam this afternoon. Sigh, better start preparing for retakes next year :L

Reply 3334

Original post by thymolphthalein

Wouldn't that be nucleophilic substituition, if it was a nucleophilic attack?

It would come from the side that the halogen is not on.

Elimination is when halogenoalkanes undergo a reaction with NaOH(or another alkali) to form an alkene, Sodium Halide and water.

I didn't mean attack I mean like this sorry can't explain..

Reply 3335

ashiekh

1

when we purify aluminium why do we put ticl4 in an argon atmosphere?

Reply 3336

Original post by ashiekh

when we purify aluminium why do we put ticl4 in an argon atmosphere?

To prevent side reactions I think

Edit: just checked to prevent side reactions with oxygen and nitrogen in air :smile:

(edited 8 years ago)

Reply 3337

ashiekh

1

Original post by samwillettsxxx

To prevent side reactions I think

Edit: just checked to prevent side reactions with oxygen and nitrogen in air :smile:

thank youuu

Reply 3338

Original post by samwillettsxxx

I didn't mean attack I mean like this sorry can't explain..

Ah yeah, that is elimination. I think your arrows are correct, we were never taught to draw the mechanism for it.

But the equation is correct.
It would form an alkene and Water and Halide ion (from the salt I mentioned earlier)

If there are unsymmetrical haloalkanes, it can form isomeric alkenes because you can shift the double bond.

Reply 3339