AQA CHEM5 A2 Chemistry - 19th June 2013

WHY does the voltmeter used to measure the p.d in an electrochemical cell have a high resistance?
In all the diagrams, I see electron flow through the voltmeter??? confusedd

Reply 1581

sikhtank27

2

I have come to the point where I know all the answers from the past papers...anyone in the same situation as me, because I did this in jan paper, and only came out with a C grade :s-smilie:

Reply 1582

Ollie:)

Original post by examgirl

Please help me with this question, its so hard

Just add up the electrons on either side of the equation. You get a 5:3 ratio. It's only confusing cause there is more than one thing being oxidised. But that is defiantly a tricky question, not many people would get that so don't sweat it too much. :smile:

Reply 1583

Beth_L_G

10

Original post by sikhtank27

I have come to the point where I know all the answers from the past papers...anyone in the same situation as me, because I did this in jan paper, and only came out with a C grade :s-smilie:

Same here, got the same grade too

Wish I got it remarked as I got the paper back and apparently my examiner didnt understand the concept of error carried forward marks

Should have got atleast a b :frown:

Reply 1584

rommy123

Original post by sikhtank27

I have come to the point where I know all the answers from the past papers...anyone in the same situation as me, because I did this in jan paper, and only came out with a C grade :s-smilie:

Hey, i was wondering if you know a good way of learning transition metals, their colors and equations?

Reply 1585

Ollie:)

Original post by sikhtank27

I have come to the point where I know all the answers from the past papers...anyone in the same situation as me, because I did this in jan paper, and only came out with a C grade :s-smilie:

Was this Jan 2013? Where did you get the mark scheme?

Reply 1586

simanana

hey can someone explain the following words with relation to writing cell equations. So, when you write a cell equation by reversing the negative half equation and then adding, what is this showing? I thought this was when the cell was 'working' so would be discharging. But on June 2012, you have to write an equation for discharging and the answer shows you're supposed to reverse the positive. Which do you reverse when it says: charging, discharging, recharged, charged?
thankyou

Reply 1587

lmccormick

can someone please send me a link to the jan 2013 past paper and mark scheme. Im desperate! :eek:

Reply 1588

im7

2

Original post by lmccormick

can someone please send me a link to the jan 2013 past paper and mark scheme. Im desperate! :eek:

Here you go:

AQA-CHEM5-W-QP-JAN13.pdf368.8KB

AQA-CHEM5-W-MS-JAN13.pdf156.5KB

Reply 1589

lmccormick

Original post by im7

Here you go:

Thank you soooo much! :biggrin:

Reply 1590

Beth_L_G

10

How is everyone revising last minute? Any tips?

I'm currently making sure I know the formula of all the oxides, their oxidation states so I know how they react together in acid-base reactions, and learning all the catalyst reaction steps

Will do some practice calculations after lunch and practice born hater after dinner

Reply 1591

bad8oy

14

Someone please attach the jan 2013 markscheme please. Would really appreciate it.

Posted from TSR Mobile

Reply 1592

Beth_L_G

10

Original post by bad8oy

Someone please attach the jan 2013 markscheme please. Would really appreciate it.

Posted from TSR Mobile

It's like 3 posts above yours

Reply 1593

mattypt

Original post by bad8oy

Someone please attach the jan 2013 markscheme please. Would really appreciate it.

They're already posted on this exact page.

Reply 1594

16dan2life

16

Original post by Electronbean

WHY does the voltmeter used to measure the p.d in an electrochemical cell have a high resistance?
In all the diagrams, I see electron flow through the voltmeter??? confusedd

It's high resistance to prevent any current from flowing in. If current flows in, potential difference will be at 0V and separate reactions will occur at each electrode.

Reply 1595

It'sMeAgain

Does anyone have a link for somewhere that tells us the TM complex's colours that AQA accepts? Unfortunately, I don't trust my text book all that much since it tells me that [CuCl4]2- is olive green, but apparently that isn't accepted in Mark Schemes.

Any help would be very much appreciated.

Reply 1596

Beth_L_G

10

Original post by It'sMeAgain

Does anyone have a link for somewhere that tells us the TM complex's colours that AQA accepts? Unfortunately, I don't trust my text book all that much since it tells me that [CuCl4]2- is olive green, but apparently that isn't accepted in Mark Schemes.

Any help would be very much appreciated.

The best thing to do is look through the past mark schemes

And the atual colour is yellow- green, which is basically the same so they will accept olive green (I wrote it in a paper and got the paper back, it was marked correct)

Reply 1597

MrMeep2580

Original post by It'sMeAgain

Does anyone have a link for somewhere that tells us the TM complex's colours that AQA accepts? Unfortunately, I don't trust my text book all that much since it tells me that [CuCl4]2- is olive green, but apparently that isn't accepted in Mark Schemes.

Any help would be very much appreciated.

[CuCl4] 2- is a yellow solution
[CoCl4] 2- is a blue solution :smile:

Reply 1598

16dan2life

16

Original post by It'sMeAgain

Does anyone have a link for somewhere that tells us the TM complex's colours that AQA accepts? Unfortunately, I don't trust my text book all that much since it tells me that [CuCl4]2- is olive green, but apparently that isn't accepted in Mark Schemes.

Any help would be very much appreciated.