OCR Chemistry F321 Exam. - [Next Tuesday[

OP

Original post by EmilyBea

anyone fancy going through ionic equations? like in general, how you construct them/charges etc. might sound obvious but i still dont fully understand them! would be greatly appreciated :smile:

They can only ask ionic equations for the reactivity of Group 7 metals anyway! That's what it specifies in the spec :biggrin:

Reply 145

Original post by EmilyBea

anyone fancy going through ionic equations? like in general, how you construct them/charges etc. might sound obvious but i still dont fully understand them! would be greatly appreciated :smile:

I've been helping some people here with them as well.

let me give you a question first to demonstrate.

What are the 2 ionic equations for magnesium's reaction with water.

a good tip is to write the full equation first.

Reply 146

JuxtaposedJames

1

Original post by Pride

I've been helping some people here with them as well.

let me give you a question first to demonstrate.

What are the 2 ionic equations for magnesium's reaction with water.

a good tip is to write the full equation first.

Ionic equations involving group 2 compounds are not on the spec

You only need to worry about halogens

Reply 147

OP

Original post by emilyannea

does anyone have the f321 for jan 2012?

Top of this page Emily! http://www.thestudentroom.co.uk/showthread.php?t=1994222&page=7&page=7 :u:

Reply 148

RandomMedic

11

On the Jan 10 past paper, there were three disproportionation reactions: with water, dilute sodium hydroxide (knew these two), but also one for hot, concentrated sodium hydroxide. The first two are in my notes & textbook, but not the last one, and I'm so confused because it was obviously one that needed to have been learnt, but wasn't in the text book :s-smilie:

Obviously I'm going to learn that one now, but I don't get how they are allowed to do that!? Unless it is in the syllabus :s-smilie:

but then why's it not in the textbook?

Reply 149

OP

Original post by Pride

I've been helping some people here with them as well.

let me give you a question first to demonstrate.

What are the 2 ionic equations for magnesium's reaction with water.

a good tip is to write the full equation first.

PRIDE - are you doing the exam tomorrow?

Stop confusing people that we need to know the ionic equations of group 2 metals. Sorry for the rant, but i'm sure people will agree with me here! We JUST need to know the ionic equations for group 7!

Reply 150

OP

Original post by Holz888

On the Jan 10 past paper, there were three disproportionation reactions: with water, dilute sodium hydroxide (knew these two), but also one for hot, concentrated sodium hydroxide. The first two are in my notes & textbook, but not the last one, and I'm so confused because it was obviously one that needed to have been learnt, but wasn't in the text book :s-smilie:

Obviously I'm going to learn that one now, but I don't get how they are allowed to do that!? Unless it is in the syllabus :s-smilie:

but then why's it not in the textbook?

Holz88 - they gave one of the products for the concentrated Naoh equation. Read the question agian :smile:

Reply 151

OP

Group 7:

Cl2 + 2Br- = 2Cl- + Br2

Cl2 + 2I- = 2Cl- + I2

:smile:

Etc

Reply 152

JuxtaposedJames

1

Original post by Holz888

On the Jan 10 past paper, there were three disproportionation reactions: with water, dilute sodium hydroxide (knew these two), but also one for hot, concentrated sodium hydroxide. The first two are in my notes & textbook, but not the last one, and I'm so confused because it was obviously one that needed to have been learnt, but wasn't in the text book :s-smilie:

Obviously I'm going to learn that one now, but I don't get how they are allowed to do that!? Unless it is in the syllabus :s-smilie:

but then why's it not in the textbook?

If I remember correctly that involved NaClO3

All they were testing is your knowledge then application of oxidation numbers

There are usually one/two a* questions in which are slightly off spec and require you to apply your knowledge of chemistry rather than just remember it. However they always give you all the information you need, there is never anything that you wouldn't be able to answer.

Reply 153

Original post by TheFootyKing19

You would lose a mark there. Mention "WEIGHTED" they seem to love that word.

= The weighted mean mass of an atom of an element compared with 1/12th of the mass of an atom of carbon 12. ---- Deffo 3 marks :wink:

oh of course, I say that definition all the time, and I missed out weighted... damn...

Reply 154

OP

Original post by Pride

oh of course, I say that definition all the time, and I missed out weighted... damn...

Anytime

Reply 155

Original post by TheFootyKing19

PRIDE - are you doing the exam tomorrow?

Stop confusing people that we need to know the ionic equations of group 2 metals. Sorry for the rant, but i'm sure people will agree with me here! We JUST need to know the ionic equations for group 7!

well yes, but you need to be able to apply and come up with them just by looking... it's in my revision guide here, oxidation of group 2 metals general formula: M --> M2+ + 2e-

Reply 156

OP

They were 9 marks available regarding definitions in Jan2012.

Generally there is always 5-6 marks recalling definitions, they always seem to ask Relative Atomic Mass, First Ionisation Energy, Orbital, Salt, Ionic Bonding, Electronegativity

Reply 157