Edexcel A2 Chemistry Exams -6CH04 (14th June) and 6CH05 (22nd June) Discussion Thread

@C0balt @Whizbox Guys would I get marks for the question about differences between D and ethanol and salicylic acid and ethanol for saying that with D you get steamy white fumes, and with D it goes to completion?

Reply 1122

Original post by Don Pedro K.

@C0balt @Whizbox Guys would I get marks for the question about differences between D and ethanol and salicylic acid and ethanol for saying that with D you get steamy white fumes, and with D it goes to completion?

I think you will

Reply 1123

Original post by C0balt

I think you will

Here's to hoping lol...

Reply 1124

Original post by Don Pedro K.

@C0balt @Whizbox Guys would I get marks for the question about differences between D and ethanol and salicylic acid and ethanol for saying that with D you get steamy white fumes, and with D it goes to completion?

Did you mention steamy white fumes of HCl?

For that question i mentioned equilibrium rather than completion and H2O rather than HCl

Reply 1125

ilovecake123

11

Original post by C0balt

I think you will

what about fumes of hcl gas evolved?

Reply 1126

Original post by Whizbox

Did you mention steamy white fumes of HCl?

For that question i mentioned equilibrium rather than completion and H2O rather than HCl

No I just said steamy white fumes :/ I mean I knew it was HCl but...xD Do you get steamy white fumes in the other one?

Reply 1127

Original post by pumelman82

I think I got the titration curve question right. What if the mark scheme for this paper says DO NOT MARK for that question because people are calling in saying it was against the spec? I may have lost 6 marks because people are protesting about a question they couldn't do, but edexcel gave you enough information to do it??? What do you think they'll do?

I hope they mark it because that twill lower the gb lol. Anyway I think it was a fair question because they didn't just throw an empty graph paper at us and told us to draw a curve for diprotic, but they gave us loads of clues - such as telling as that two moles of OH- is required to neutralise one mole of H2S, the values of two Ka (and if you knew about half neutralisation point you'd know what points to plot), initial pH, telling us to indicate equivalence pointS (implying that there was more than one)...

Reply 1128

Original post by Don Pedro K.

No I just said steamy white fumes :/ I mean I knew it was HCl but...xD Do you get steamy white fumes in the other one?

I don't think you would get steamy fumes in the other one, but it depends on what the mark scheme says, you may get it

Reply 1129

Original post by ilovecake123

what about fumes of hcl gas evolved?

I think you'll get a mark for that. I hope so anyway i just said HCl gas forms for D but not for the acid lol

Reply 1130

dj3k

For how you know the acid is in excess I wrote that the salt (or whatever it was) stops precipitating out of the solution. I also wrote that you can add Sodium Carbonate and you'll observe effervescence and fizzing. Would this get the mark?

Reply 1131

Original post by C0balt

I hope they mark it because that twill lower the gb lol. Anyway I think it was a fair question because they didn't just throw an empty graph paper at us and told us to draw a curve for diprotic, but they gave us loads of clues - such as telling as that two moles of OH- is required to neutralise one mole of H2S, the values of two Ka (and if you knew about half neutralisation point you'd know what points to plot), initial pH, telling us to indicate equivalence pointS (implying that there was more than one)...

The two vertical regions were at 25cm3 and 50cm3 right?

Reply 1132

ilovecake123

11

Original post by C0balt

I think you'll get a mark for that. I hope so anyway i just said HCl gas forms for D but not for the acid lol

same
you know to the titration curve what do you think the point break down will be? and did you do a vertical region at 50cm3?

Reply 1133

Original post by Whizbox

I don't think you would get steamy fumes in the other one, but it depends on what the mark scheme says, you may get it

Hope so lol

Reply 1134

Original post by Whizbox

The two vertical regions were at 25cm3 and 50cm3 right?

yeah

Reply 1135

pumelman82

Original post by C0balt

I hope they mark it because that twill lower the gb lol. Anyway I think it was a fair question because they didn't just throw an empty graph paper at us and told us to draw a curve for diprotic, but they gave us loads of clues - such as telling as that two moles of OH- is required to neutralise one mole of H2S, the values of two Ka (and if you knew about half neutralisation point you'd know what points to plot), initial pH, telling us to indicate equivalence pointS (implying that there was more than one)...

Exactly.... I felt that paper could have been a lot worse. Yes they asked unusual stuff but you weren't completely in the dark about how to answer stuff. They gave more than enough clues.

Reply 1136

chemica

2

Original post by Science&Despair

Im thinking 66 for an A grade

I pray to god that is the case!!

Reply 1137

Anyone got an unofficial mark scheme going??

Reply 1138

Original post by ilovecake123

same
you know to the titration curve what do you think the point break down will be? and did you do a vertical region at 50cm3?

how many marks was that curve?
I think points to look out for are
- vertical sections at 25 and 50
- start at pH 1.5
- end at pH 12-13
- pH 1.9 (iirc) at 12.5cm3
- pH 7.2 (iirc) at 37.5cm3
- general shape
- marking equivalence points at middle of vertical sections

Reply 1139