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# OCR A2 CHEMISTRY F324 and F325- 14th and 22nd June 2016- OFFICIAL THREAD watch

1. It was the same shape as water, i swear thats non-linear or bent shaped
(Original post by suibster)
the shape is linear
2. (Original post by cr7alwayz)
Can anyone explain how x=4 for the last question if you remember your working out.
You work backwards through the titration to find the moles of Cu2+. Then you multiply the moles of Cu2+ by the molecular mass of Cu(HCOO)2 to find the mass in grams. Then you subtract this value from the grams they gave you in the question. Then you use the remaining grams to find the moles of water. Using moles equals mass over molar mass. Then lastly you divide the moles of water by the moles of the Cu2+ to get the molar ratio.
3. (Original post by HFancy1997)
im sure it was Alkaline...

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yeah it was alkaline since more contraption of oh- ions than h+ so acidic is wrong I'm afraid
4. Have a feeling grade boundaries could be 67-73 for an A, 75-81 for A*.
you are literally so annoying, me and 3 others from my college that are going to oxbridge said that it was definitely harder than last years and a lot of people found it hard. don't be so patronising to the other people you snob
Agreed! Definitely not harder than last years and won't have higher UMS I think it will be around 90->82>76... -> 150>135>120
6. X=4 q was bare cute
7. The pH was given as 7 so I worked out the conc of h+ then divided kw by that to give OH-
OH- > H+ so I put alkaline

Anyone else?
8. Which question was the pH 2.12 for?
9. For the equilibrium question I put: I- reacts with Ag to form agI (yellow ppt), therefore the position of equilibrium will shift to the left to restore I- conc. As a result, more aqueous iodine was formed so the position of equilibrium of 1 will also shift to the left, therefore more grey/black solid iodine is formed. For the electrochemistry question I needed up with two equations. The oxidising agent one where Cr+3 reacts with AL and the reducing agent one where Cr+3 reacts with feO4- or something. Anyone else?
10. I agree with u man, i think i grabbed the A mark but being honest that paper was relatively harder than last years, GB for last year was 79 for an A. if you find the paper easy have the common decency to not brag and think about others.
you are literally so annoying, me and 3 others from my college that are going to oxbridge said that it was definitely harder than last years and a lot of people found it hard. don't be so patronising to the other people you snob
11. (Original post by cr7alwayz)
Can anyone explain how x=4 for the last question if you remember your working out.
I worked out the moles using the info they gave.
Divided it by 2 because of the mole ratio.
Then multiplied by 2 because of the mole ratio.
Multiplied that by 10 because it was in 250cm3.
Worked out the mr by 2.226 divided by the moles I worked out.
Subtracted the mr of cu(choo)2 from the mr calculated.
Then divided the answer by 18, I got 3.5, so 4=X
12. (Original post by HFancy1997)
Everything correct except for the first number, it said 2 sf so 0.029

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Wasn't it also supposed to be given in standard form?
13. (Original post by Serine Soul)
Yes bois

I think I lost a mark on the first one for wrong s.f :/

And the buffer one, you were simply adding x moles NO2-...
Don't worry you'll be fine.

Speaking to people who sat the exam with me, lots of them messed up the buffer question.

I certainly messed up parts. But with high UMS last year, and good UMS in the first exam, I should have the A I need.
14. (Original post by Sahil_)
It asked whether a ph of 7 is acidic/alkaline at 60 degrees, so using the new Kw, you get that the concentration of oh- is larger than the conc of H+ so it is alkaline
exactly what I got!!
15. (Original post by maisym00)
For the equilibrium question I put: I- reacts with Ag to form agI (yellow ppt), therefore the position of equilibrium will shift to the left to restore I- conc. As a result, more aqueous iodine was formed so the position of equilibrium of 1 will also shift to the left, therefore more grey/black solid iodine is formed. For the electrochemistry question I needed up with two equations. The oxidising agent one where Cr+3 reacts with AL and the reducing agent one where Cr+3 reacts with feO4- or something. Anyone else?
Yes for thr 6 Marker Half cells q

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16. (Original post by Vannzzoo)
I worked out the moles using the info they gave.
Divided it by 2 because of the mole ratio.
Then multiplied by 2 because of the mole ratio.
Multiplied that by 10 because it was in 250cm3.
Worked out the mr by 2.226 divided by the moles I worked out.
Subtracted the mr of cu(choo)2 from the mr calculated.
Then divided the answer by 18, I got 3.5, so 4=X
the answer was 4.0002 exactly so i don't know how you got 3.5? lucky assumption i guess
17. I think honestly this will be an average paper in terms of grade boundaries, people will have made silly mistakes where they don't expect just like the F324 exam which will pull the marks people think they have got down a bit.
18. (Original post by mosheezie)
Piss easy FULL UMS FOR ME! My whole college said it was easy af, you guys stop stressing!
A* -90
A - 85
Everything below mehh......
hahahaha what a c*unt
19. (Original post by BioStudentx)
HIO + OH- for step 1, instead of what you got.
H + I- --> HI
HI + H2O2 --> intermediate for given step

Is what I got for Step 1 and 2
20. (Original post by SazahSauce)
It was the same shape as water, i swear thats non-linear or bent shaped
Water has bond angles of 104.5 degrees and a shape of bent / non-linear

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