AQA Chemistry A2 Unit 5: Energetics, Redox and Inorganic Chemistry - 22nd June 2016

can someone help me with this question 5b(i) to 5(b)iv its structure determinationI got the answer right when asked to deduce the structure of P, BUT my structure was the other way around, (so the same as the mark scheme if read in the opposite direction) do you get penalised for this, as i didnt see anything that said you would in the additional comments. if you do, then can someone explain to me how you know which way to draw the structure. thank you! past paper question 5biv: http://filestore.aqa.org.uk/subjects/AQA-CHEM4-QP-JAN13.PDFmark scheme: http://filestore.aqa.org.uk/subjects/AQA-CHEM4-W-MS-JAN13.PDF

This would be okay I would think, because it has the same name

Reply 21

username986184

3

Original post by woojinhyuk

Sorry. I meant why is it not called
3-Bromo-2-methylbutane

For example

Reply 22

username986184

3

Original post by chzm

can someone help me with this question 5b(i) to 5(b)iv its structure determinationI got the answer right when asked to deduce the structure of P, BUT my structure was the other way around, (so the same as the mark scheme if read in the opposite direction) do you get penalised for this, as i didnt see anything that said you would in the additional comments. if you do, then can someone explain to me how you know which way to draw the structure. thank you! past paper question 5biv: http://filestore.aqa.org.uk/subjects/AQA-CHEM4-QP-JAN13.PDFmark scheme: http://filestore.aqa.org.uk/subjects/AQA-CHEM4-W-MS-JAN13.PDF

No need to worry.

Reply 23

woojinhyuk

5

Original post by TeachChemistry

Substituents in alphabetical order (as you have done) then lowest numbers assigned overall in order. If you do it the other way round in an exam I doubt you'd be penalised.

Thanks but I still don't understand why
2-Bromo-3-methylbutane is correct. In the textbook it says to number it so that the highest priority group is the lowest number (which in this case is the alkyl group). Maybe I'm missing something or just confused lol

Reply 24

username986184

3

Original post by woojinhyuk

Thanks but I still don't understand why
2-Bromo-3-methylbutane is correct. In the textbook it says to number it so that the highest priority group is the lowest number (which in this case is the alkyl group). Maybe I'm missing something or just confused lol

Read these links

https://chemlaba.wordpress.com/2011/03/12/iupac-nomenclature-of-alkyl-halides/

http://www.chem.uiuc.edu/GenChemReferences/nomenclature_rules.html

The names I gave above for three examples were generated using a chemical drawing package with IUPAC naming software incorporated into it.

Reply 25

woojinhyuk

5

Original post by TeachChemistry

Read these links

https://chemlaba.wordpress.com/2011/03/12/iupac-nomenclature-of-alkyl-halides/

http://www.chem.uiuc.edu/GenChemReferences/nomenclature_rules.html

The names I gave above for three examples were generated using a chemical drawing package with IUPAC naming software incorporated into it.

These links are quite helpful. Thanks for the help.

Reply 26

tayoo

1

Original post by Larashax

Here you go 😊

Please, do you have page 158 also ?

(edited 7 years ago)

Reply 27

Scarly9

2

Original post by chzm

how do you know when to include the platinium electrode in cell representations?

When the two species are of the same state or do not conduct electricity on their own.e.g. fe2+ions and fe3+ ions and then the standard hydrogen gas but also could potentially be helium gas but i doubt they would bring that up in an example

Reply 28

username1599987

12

I thought Cr3+ and [Cr(H2O)6]3+ are the same thing. But they have different colors? So what's going on?

Reply 29

Aimen.

7

I know it's too late but could someone please help me with this? :3

Why is it not B?
@TeachChemistry please or anyone else?

Reply 30

Ben :)

2

Original post by Aimen.

I know it's too late but could someone please help me with this? :3

Why is it not B?
@TeachChemistry please or anyone else?

The answer was D right?, I would personally guess that the H2SO4 may not fully dissociate and would only dissociate into HSO4- so the concentration of H+ isn't quite 1 mol dm-3!

Reply 31

Larashax

1

Original post by Aimen.

I know it's too late but could someone please help me with this? :3

Why is it not B?
@TeachChemistry please or anyone else?

Hey,

It's D because one atmospheric pressure is equal to about 100 kPa

Hope it helps

Reply 32

Wally West

8

Original post by Aimen.

I know it's too late but could someone please help me with this? :3

Why is it not B?
@TeachChemistry please or anyone else?

STANDARD (therefore has to be in standard conditions) Hydrogen electrode; ONE mole, and 100KPa (aka about 1atm)
B is saying in 0.5 mol... not one mol hence its incorrect :smile:

Reply 33

wannabemedic1234

1

How did you guys find the paper?!

Reply 34

ahlam H

4

It was good and better than unit 4

Reply 35

J9876

1

One of the easiest ive done, much easier than chem 4

Reply 36

username2326241

2

I thought it ws ok :smile:

Reply 37

Maligaha

1

Did any one get 94.4% for percentage purity

Reply 38

Larashax

1

Original post by Maligaha

Did any one get 94.4% for percentage purity

I got 64.7% 🙈

Reply 39

Rid123

11

Thought it was a pretty standard paper, much much better tha unit 4 ahaha :/
Calculaions that i remember are
Latt dis: 2328
Delta h sol: -155
Delta h: -196
Delta s: -189 jmol^-1
Delta g: -135
Substance x i got as P
Amphoteric substance al2o3
Weakest oxidising agent is zn2+ i think
Copper contain compound cu2+
H2->2H+ +2e-
2h2o+o2+4e-->4oh-
Dunnon if i remeber much else im guessing 80-83ish for A?? But then again we can only guess

(edited 7 years ago)

AQA Chemistry A2 Unit 5: Energetics, Redox and Inorganic Chemistry - 22nd June 2016

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you