If I didn't get the formula right at the start of the percentage purity calculation question but did the calculation in the right way, with the wrong figures, do you think that I would loose all the marks for that question?

Reply 2985

Sloth45

I have a couple of questions: was it ok to use conc. excess NH3 for the last Chromium reaction? And will they accept multiples for the hydrogen/oxygen fuel cell?

Reply 2986

Sloth45

Original post by Whitbyfish

If I didn't get the formula right at the start of the percentage purity calculation question but did the calculation in the right way, with the wrong figures, do you think that I would loose all the marks for that question?

Nah, you'll get ecf for the ratio because that's the only thing wrong in your calculation

Reply 2987

emilies18

1

couple of Qs- most outlined in bold pink on here:
https://docs.google.com/document/d/1smR3w_XZhzLCLrqIQ_U69a47b3KLGJoEbjqyFy7Ss84/edit
would someone be kind enough to anwser

Reply 2988

Suits101

2

Original post by Sloth45

I have a couple of questions: was it ok to use conc. excess NH3 for the last Chromium reaction? And will they accept multiples for the hydrogen/oxygen fuel cell?

No to first
Yes to second

Original post by emilies18

couple of Qs- most outlined in bold pink on here:
https://docs.google.com/document/d/1smR3w_XZhzLCLrqIQ_U69a47b3KLGJoEbjqyFy7Ss84/edit
would someone be kind enough to anwser

You need to sort them grade boundaries out... How can there be a 12 raw mark gap for full UMS haha?

Full = 94
A* = 87

About this area In my opinion

Reply 2989

mojogigi1234

1

Original post by Whitbyfish

If I didn't get the formula right at the start of the percentage purity calculation question but did the calculation in the right way, with the wrong figures, do you think that I would loose all the marks for that question?

what formula do you mean? the equation?

Reply 2990

emilies18

1

Original post by Suits101

No to first
Yes to second

You need to sort them grade boundaries out... How can there be a 12 raw mark gap for full UMS haha?

Full = 94
A* = 87

About this area In my opinion

I didn't make that I just added. Where do you think the boundary for an A will be?

Reply 2991

Suits101

2

Original post by emilies18

I didn't make that I just added. Where do you think the boundary for an A will be?

I have no idea sorry... But full UMS was very high on that link

Reply 2992

Whitbyfish

1

Original post by mojogigi1234

what formula do you mean? the equation?

The equation for the reaction so the ratios for the calculation were wrong

Reply 2993

mojogigi1234

1

Original post by Whitbyfish

The equation for the reaction so the ratios for the calculation were wrong

yeah, i dont think youll get any marks for it if the equations wrong

Reply 2994

irendeep

Original post by Spectral

Yes. You can read the previous posts for the full explanation why

If you have a look at June 2011 question 3 it asks to calculate Delta S for the harber process and u had to divide by two to get the correct answer please explain to me how today was different? Thanks.

Reply 2995

Fibsy

9

Can grade boundaries for A* possibly be higher than 89?

Posted from TSR Mobile

Reply 2996

The Informant

6

Original post by Fibsy

Can grade boundaries for A* possibly be higher than 89?

Posted from TSR Mobile

The highest it has been is 84 (2015).

Reply 2997

slb971

4

For the final part of Chromium question with excess OH-, would [Cr(H2O)2(OH)4]- be acceptable or not? I remember seeing a couple textbooks had this instead of [CR(OH)6]3-

Reply 2998

Spectral

8

Original post by irendeep

If you have a look at June 2011 question 3 it asks to calculate Delta S for the harber process and u had to divide by two to get the correct answer please explain to me how today was different? Thanks.

Again, I urge you to read previous posts, because I've already answered that question (you'll see what I mean)

To put it shortly, that question asks for enthalpy of formation which is by definition 1 mol (so you divide)
The question in the exam was enthalpy of reaction, not formation, so the 1 mol principle does not apply here

The point I'm making is not debatable I'm afraid. You will lose around 1-3 marks depending on the generosity of the AQA examiners

Reply 2999

irendeep

Original post by Spectral

Again, I urge you to read previous posts, because I've already answered that question (you'll see what I mean)

To put it shortly, that question asks for enthalpy of formation which is by definition 1 mol (so you divide)
The question in the exam was enthalpy of reaction, not formation, so the 1 mol principle does not apply here

The point I'm making is not debatable I'm afraid. You will lose around 1-3 marks depending on the generosity of the AQA examiners

Im not refering to delta H im refering to delta S.

Aqa chem 4/ chem 5 june 2016 thread

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