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Aqa chem 4/ chem 5 june 2016 thread

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Reply 3020

TJ_gym

how many marks for 51%?/?

Reply 3021

Cadherin

Original post by RedNebula

My guess for what I think I got on this paper is about 68. How close do you think this would be to the A boundary?

Thanks :smile:

Best of luck to you all

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I'm afraid I think that might be a high C/low B :frown:

- who knows though, grade boundaries might go down for all we know though.

Reply 3022

Cadherin

Original post by Suits101

I agree with these (second quote)

I agree too - although I unfortunately think they may even be slightly higher.

Reply 3023

Humza Ali

what was the answer for the platinum electrode question guys? did it have any effect?

Reply 3024

SirRaza97

Does anyone have any idea what the bondaries will be for the CHEM4 paper? I was just wondering since chem5 will seem to be a bit higher

Reply 3025

Cadherin

Original post by SirRaza97

Does anyone have any idea what the bondaries will be for the CHEM4 paper? I was just wondering since chem5 will seem to be a bit higher

My guesses:

CHEM4:
120 UMS = 88/100
108 UMS = 81/100
A = 74/100

CHEM5:
120 UMS = 93/100
108 UMS = 85/100
A = 77/100

But this is of course just guesswork - I'm usually quite accurate though!

Reply 3026

Cadherin

Original post by Humza Ali

what was the answer for the platinum electrode question guys? did it have any effect?

Surface area of electrode: No effect.
Increased oxygen pressure: Higher emf.

Reply 3027

emilies18

I think I got around 80-82 on this paper. Do you think that will be an A?

Reply 3028

username1831327

Original post by Aethrell

Still don't get why increasing the pressure of the oxygen would make a difference... surely they're not all gaseous so it wouldn't make a difference?

When you're measuring E0 it must be under standard conditions else it will change (so 100kPa) so increasing the pressure will make a difference purely becuse it's no longer under standard conditions

Reply 3029

Bigboss27

Wasnt lattice dissociation enthalpy negative not positive?

Reply 3030

Telgar_45

Could you put equlibrium signs in the contact process equations? Would I drop the marks with even with the equations I put correct?

Reply 3031

Ukrainian Doctor

ImageUploadedByStudent Room1466678805.052507.jpg

Grade boundaries should be high according to my Twitter poll.

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Reply 3032

palacefloor

Original post by Bigboss27

Wasnt lattice dissociation enthalpy negative not positive?

The arrow on the diagram went the wrong way so you had to change the sign to get a positive. Also it doesn't really make sense if you're breaking up a lattice that it would give out energy.

Reply 3033

DDan123

Original post by emilies18

I think I got around 80-82 on this paper. Do you think that will be an A?

Most likely. The paper was similar in difficulty to last year and you only needed 76 for an A :smile:

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Reply 3034

chloeabeki

Original post by Medlad101

**** i did the same

its probably fine. They didn't ask us to clearly show the type of bonding in the complex.

Reply 3035

emilies18

Can someone help me out with a few Qs- for the one about environment , can you just put h20 only product or do you have to hammer on about it not being as bad as co2? Also on the Q (7 marks) about adding ethanediol te to co2+ do you have to say delta H is the same ?:/ also the very last Q - can you say: mn04- absorb white light frequencies and the freq not absorbed detected by colouring ter to give value of conc

Reply 3036

ravichauhan11

would it be ok to put + aq on the reactants side of the enthalpy of solution equation? or will it just say ignore +aq on the mark scheme?

Reply 3037

Kings_queens

has anyone done a chem 4 unofficial markscheme?

Reply 3038

Tokhmehsag

For the percentage purity I put two calculations one for C2O4 and one for Fe on an extra sheet ,I didn't cross any out ,do I get a few marks or not ???

Thank you

Reply 3039

j5994

does anyone have pictures of the paper? would be much appreciated xoxo