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Edexcel 6BIO7/01 (International Unit 3B) ~ 7th May 2013 ~ AS Biology

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Reply 640

Relaxedexams

Original post by StUdEnTIGCSE

OK.

So the observation should have been no white precipitate formed.
Will they mark KI wrong if I had written white precipitate formed?

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Maybe white ppt formed and it dissolved in in HCl?

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Reply 641

TheKingOfTSR

Original post by StUdEnTIGCSE

OK.

So the observation should have been no white precipitate formed.
Will they mark KI wrong if I had written white precipitate formed?

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No.
They will assume that you thought that that observation was for no sulphate present. So that point you will lose but ki you will get.

Reply 642

TheKingOfTSR

Original post by Relaxedexams

Maybe white ppt formed and it dissolved in in HCl?

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So then sulphite could be present? I think you should say effervescence seen as sulphite ion can also be considered as sulphate iv ?

Reply 643

RoyalBlue7

Original post by Relaxedexams

Maybe white ppt formed and it dissolved in in HCl?

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I added "and remains".

Original post by TheKingOfTSR

No.
They will assume that you thought that that observation was for no sulphate present. So that point you will lose but ki you will get.

No ECF is when you get it wrong, isn't it?

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Reply 644

TheKingOfTSR

Original post by Relaxedexams

KI

No need to take mass of zn into consideration. Only mass of CuSO4 solution.

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Why "no need to take mass of zn"?
:confused:

Reply 645

RoyalBlue7

Original post by TheKingOfTSR

Why "no need to take mass of zn"?
:confused:

Because never in the past papers it was so.

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Reply 646

KhawlaM

Original post by TheKingOfTSR

Why "no need to take mass of zn"?
:confused:

I think maybe because it has a negligible heat capacity, or because it was added in excess, I'm not really sure.

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Reply 647

TheKingOfTSR

Original post by StUdEnTIGCSE

Because never in the past papers it was so.

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Original post by KhawlaM

I think maybe because it has a negligible heat capacity, or because it was added in excess, I'm not really sure.

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No.
The question clearly stated : calculate the heat transferred to the mixture!
And assume the specific heat capacity of the mixture.....
Mixture means solid and liquid ..right?
And the equation given was NOT mass of solution * .... it was just mass!
Zn is used up.....it just not stay just intact...thus we must consider its mass too
:biggrin:

Reply 648

TheKingOfTSR

This is the biology thread right..... :frown:

Forgive me for discussing chemstuff

Reply 649

RoyalBlue7

Original post by TheKingOfTSR

That's hilarious.
But did you get exact answers in your calculations?

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Reply 650

NilFBosh

Here is the download link to the paper! Not the marking scheme only the paper
https://www.facebook.com/download/378014078979018/AL%20Biology%20Unit%203%20B%20May%202013-1.pdf

Reply 651

kiasha

Original post by TheKingOfTSR

Why "no need to take mass of zn"?
:confused:

we are taking the specific heat capacity of the solution right? (well technically it is specific heat capacity of water) then the energy would be absorbed into the solution..so i guess we have to take the mass of the solution into consideration to calculate the amount of energy. gosh i hope im not wrong!!! i made such stupid mistakes on the paper