OCR chemistry trends and patters + option (TE's for me)

roma1987

so guys its all over!!!

how did everyone find it?

i found T&P quite tough actually, especially the calculations, couldnt really do them :frown:

and the iron question ARGH!

i found transition element not too bad, again the calculation question was the one i found the hardest.

Reply 1

stratomaster

It wasn't a bad paper I thought, I can't actually remember many of the questions though :s

Did you get 9 for the value of x?

The calculations on transition elements were a bugger I agree.

Reply 2

roma1987

OP

1

i think i got the x one wrong, i know some other people in my year got 9, i got 4 :frown:

what percentage did u get?

for the transition element calculation i got some weird ratio of like 1:1.6 and just played around with numbers.

Reply 3

HomerJ

Yeah i thought trends and patterns was kinda hard- i didnt like the calculations either- i cnt rmbr what i got for x, did somre random calculation! And the one about % of Cu in bronze was a bit wierd...i got summit like 83%.
I did methods of analysis and detection unit, and I thought that paper was ok actually, no paper chromatography which I hate!

Reply 4

stratomaster

I think I got 80 something % for Bronze.. I always forget nearly everything once I step outta the exam hall lol

Reply 5

roma1987

OP

1

yeah i think i got 84% for that one.....cant remember though.

does anyone remember what lattice enthalpy they got?

Reply 6

appletizer

what did u all get for the lattice enthaly evry1 i asked got sumthin different

Reply 7

roma1987

OP

1

huh?

i got something like -2500

Reply 8

appletizer

for the X one i got 5, i think it was around 4.8 what i calculated, but im no mathematician. I worked out the mass of the things in it without the water, which was 84%, so I divided it by 84 to get 1% timesed it by 16 and (thought) i'd got the mass of water which i divided by Mr of water which is 18. Is this really stupid? What was the actual answer, ooooooooh i hope the rest of my paper was better than this :frown:

Reply 9

HomerJ

Oh good, looks like 80 summit % was about right then.
For lattice enthalpy, um it was quite a high value, maybe -1600 or -2600, i forget.
Did anyone doe methods of analysis and detection?

Reply 10

Aired

1

The value of X was 5 I think. You had to work out the total mass by calculating the Mr of the molecule without water, divide by 84 (as it was 84% of the compound by mass) then multiply by 100% to get the total mass. The Mr of XH₂O came out as 89.5 or something, divide this by 18 and you get 4.9 ~ 5.

I got 83/84% for the bronze question, and my latice enthalpy was -2500ish

Reply 11

HomerJ

Hmm, maybe i did get the water one ok- it confused me, i just found the Mr of that molecule, then find the % of the Mr, then divided by 18. it was kinda a guess, might aswell put something down if u have no clue, might get a mark!
I remember my lattive enthalpy being high...im not sure exactly, got a horrible feeling it was like -1600, but not sure.

Reply 12

roma1987

OP

1

hmmm so my calculations are like half right...maybe i picked up one or two marks on a few of them.
i got -2500ish for LE.

did anyone esle find the iron question a bit weird?

and also is there a new examiner or something cos the paper i found really different to past papers and like 1 mark for quite tough questions?

Reply 13

roma1987

OP

1

HomerJ

Hmm, maybe i did get the water one ok- it confused me, i just found the Mr of that molecule, then find the % of the Mr, then divided by 18. it was kinda a guess, might aswell put something down if u have no clue, might get a mark!
I remember my lattive enthalpy being high...im not sure exactly, got a horrible feeling it was like -1600, but not sure.

yeah i did that for X, but for some reasonn i got 4...i know im wrong though.

Reply 14

Aired

1

I thought the iron question was quite good, I put...

~ Ligand exchange: Iron (III) with SCN^-

~ Precipitation: Iron (III) solution with sodium hydroxide solution

~ Redox: Iron(II) with potassium manganate

Reply 15

HomerJ

Yeah, i did alot of past papers last night, and they were generally ok- but thought this one was a bit harder, and the claculations weren't like the usual ones i'd seen- hate it when they add wierd additions like % to them, kinda makes u a bit more ahhh when u look at it!
The iron one was scary at first, I couldnt think of a redox reaction :frown:

so just explained what a redox reaction was. I think i understood the ligand and precipitate reactions though (hydroxide precipitates of Fe(OH)2 and Fe(OH)3 when added to Fe2+ and Fe3+ respectively), when NaOH added i put..) :confused:

Reply 16

appletizer

i no this was only worth one mark but it is frustratin me loads. before the big essay thing there was a question which said Cl2O7 or something similar was a simple molecule. suggest one chemical property you would expect, and as soon as i saw simple molecule i thought "boiling point" but thats not chemical? so anyway I made something up - just wondered what everyone else got

Reply 17

Aired

1

appletizer

i no this was only worth one mark but it is frustratin me loads. before the big essay thing there was a question which said Cl2O7 or something similar was a simple molecule. suggest one chemical property you would expect, and as soon as i saw simple molecule i thought "boiling point" but thats not chemical? so anyway I made something up - just wondered what everyone else got

It was a non-metal chloride so I said it will react with water to give an acidic solution

Reply 18

roma1987

OP

1

yeah i couldnt remember the redox reaction for iron and mangenate....so i just made one up,

i did do the other two fine though, i hope i picked up enough marks through those.

in my past papers i was doing well getting marks in the 90%'s and could do all the calculations, this one though..meh hate it when they bring that 24 thing in.

Reply 19

HomerJ

yeah that bugged me too! I just said forms acids when dissolved in water, as non-metal oxides are acidic oxides- but I left it blank at first lol.

OCR chemistry trends and patters + option (TE's for me)

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