Turn on thread page Beta
 You are Here: Home >< GCSEs

# AQA GCSE Chemistry C2/C3 May 15th 2014 watch

Announcements
1. Calculate the percentage yield if 9.0g MgSO4 was made from 4.0g MgO.

I knew how to do this before, but I've spent 30 minutes trying to work this out? CHESWDCKJNEWLksmdc.m sdkj
The answer is 75%. Please explain. -_-
2. (Original post by rm_27)
Calculate the percentage yield if 9.0g MgSO4 was made from 4.0g MgO.

I knew how to do this before, but I've spent 30 minutes trying to work this out? CHESWDCKJNEWLksmdc.m sdkj
The answer is 75%. Please explain. -_-
What's the reaction equation?

Posted from TSR Mobile
3. (Original post by majmuh24)
What's the reaction equation?

Posted from TSR Mobile
It's not given. I think they assume we should know it.
4. (Original post by rm_27)
It's not given. I think they assume we should know it.
I assume it's MgO + SO3 ==> MgSO4 then (was there something to do with acid rain?)

1 mol. Mg ==> 1 mol. MgSO4

RMM magnesium is 24
RMM oxygen is 32
RMM sulfur is 16

Using this, we get that

56g MgO ==> 168g MgSO4

Dividing by 14 gives

4g MgO ==> 12g MgSO4

And the problem is easy from there

Posted from TSR Mobile
5. (Original post by rm_27)
It's not given. I think they assume we should know it.
Sorry but I don't know >.<
6. (Original post by Silver-wind)
Come at me brah
Please give me any tips you have
7. Oxygen is 16...sulfur 32 :P
8. okay so basically the relative atomic masses first
oxygen =16
sulfur=32
magnesium=24

so mgo---> mgS04

mgo=24+16=40
mgso4 = 24=16=(16x3)=120

so its 40:120
which can be cancelled to 4:12
so 12g of mgso4 should be produced
actual/theoretical X 100 to get the percentage yield right
so 9/12 = 0.75x100 = 75% not that hard theyre just trying to be confusing!
9. Anyone got any thoughts on what the 6 marker will be on C2? Based on previous years etc?
10. (Original post by chronicmusic)
Please give me any tips you have
Got a feeling about whats going to come up in the exam, it came to me and the more I think about it the more it makes sence!
11. (Original post by Kevin Paul Beale)
Got a feeling about whats going to come up in the exam, it came to me and the more I think about it the more it makes sence!
and whats that then
12. Do you guys think anything on nano particles will come up? Or precipitation reactions? Titration was last year, but could it be repeated?
13. (Original post by Kevin Paul Beale)
Got a feeling about whats going to come up in the exam, it came to me and the more I think about it the more it makes sence!
Have you got the Folens revision guide? It's really good for downloading powerpoints and claiming they are your own work that took you 12 hours!
14. Predicted 6 markers for C2:

I believe there will be 2 six markers, the first on nanoscience (uses and what nanoparticles are) and the other on polymers (platics, thermosoftening/setting, exothermic/endothermic). Only one will be a QWC though so you'll need about 4/5 points each
15. (Original post by chronicmusic)
Predicted 6 markers for C2:

I believe there will be 2 six markers, the first on nanoscience (uses and what nanoparticles are) and the other on polymers (platics, thermosoftening/setting, exothermic/endothermic). Only one will be a QWC though so you'll need about 4/5 points each
nanoscience has loads of points, polymers I can think of maybe 2/3 for each
16. (Original post by voxdock)
nanoscience has loads of points, polymers I can think of maybe 2/3 for each
Yeah true, would you mind listing your points to help me/other people out?
17. Can someone please explain to me how to make insoluble salts? I tried CGP and my-gcsescience but I still can't understand.
18. (Original post by chronicmusic)
Yeah true, would you mind listing your points to help me/other people out?
nanoparticles-1-100nm in length, inc fullerenes
nano science: fullerenes
huge SA:vol so industrial catalysts
nanomedicine-absorbtion by body
cosmetics
buildings
strong covalent bonds, so strong
conductrors-computer parts
sun cream
19. My teacher has a strong feeeling that electrolysis is going to be on the c2 exam for the 6 marks...im really worried an unprepared for this exam!

Posted from TSR Mobile
20. (Original post by kkomde)
Can someone please explain to me how to make insoluble salts? I tried CGP and my-gcsescience but I still can't understand.
I will use silver chloride as an example. Silver chloride is insoluble. You need a soluble silver salt and a soluble chloride salt to make it. Silver nitrate and sodium chloride are both soluble. When you mix their solutions together, you make soluble sodium nitrate and insoluble silver chloride:

• silver nitrate + sodium chloride → sodium nitrate + silver chloride
• AgNO3(aq) + NaCl(aq) → NaNO3(aq) +AgCl(s)

The silver chloride appears as tiny particles suspended in the reaction mixture - it forms a precipitate. The precipitate can be filtered, washed with water on the filter paper, and then dried in an oven.
Remember: if you want to make an insoluble salt XY, mixing X nitrate with sodium Y will always work. In the example above, X is silver and Y is chloride.

Turn on thread page Beta
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: November 26, 2014
Today on TSR

### Lied on my UCAS

And my school told me not to change it

### University open days

• University of Derby
Postgraduate and Professional Open Evening - Derby Campus Postgraduate
Tue, 22 Jan '19
• University of the West of England, Bristol
Undergraduate Open Afternoon - Frenchay Campus Undergraduate
Wed, 23 Jan '19
• University of East London
Wed, 23 Jan '19
Poll
Useful resources

## Study tools

### Essay expert

Learn to write like a pro with our ultimate essay guide.

See where you can apply with our uni match tool

### Ask a question

Chat to other GCSE students and get your study questions answered.

### Make study resources

Create all the resources you need to get the grades.

### Create your own Study Plan

Organise all your homework and exams so you never miss another deadline.

### Resources by subject

From flashcards to mind maps; there's everything you need for all of your GCSE subjects.

### Find past papers

100s of GCSE past papers for all your subjects at your fingertips.

## Help out other students

Can you help? Study help unanswered threads

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE