Year 12s: what will be the first way you research your future options? >>

OCR A level Chemistry Unified Chemistry paper 3 pre-exam discussion

Final OCR chem exam on June 20th!!! Hey guys i don't know about you but I found physical chemistry a blessing of a paper, however that organic paper was satans baby and was absolutely vile. So... I'm relying on smashing paper 3 to pull my grade up.

Lets work together to collate resources for this final paper?! Anyone that has any advice/tips on how to tackle unfamiliar questions, and revision strategies for this paper, please do share. Kiki xx

Scroll to see replies

Reply 1

Parmaar

Original post by Kiki99

I'm in same boat as you except I found both hard but what you reckon will come up

Reply 2

Alizarinn

I loved the physical but hated the organic too! (synthesis is my worst enemy)

I reckon there will be a lot more on transition metals, some buffer questions, Kp and amines
I can't remember whether there were many questions on entropy or free energy, so maybe some stuff on that?

Reply 3

ahhhhhhhh1

Buffers didn't come up much in physical, and Gibb's free energy didn't come up at all so reckon they're a shoe-in too

Reply 4

roseprincessx

Expect a 6 marker on like practicals in paper 3 x
We can do this guys

Reply 5

luce12341

Feel like there will be a Q=mcdeltaT question, definitely some entropy, maybe storage/fuel cells, purification techniques, some kind of free radical substitution
Oh and for revision i recommend watching loads of machemguy videos on youtube he is the best

(edited 5 years ago)

Reply 6

green505

Does anyone else find the paper 3 really hard. I have done the sample papers and have found them soooo difficult. It is making me panic.

Reply 7

elliew8

Original post by green505

Does anyone else find the paper 3 really hard. I have done the sample papers and have found them soooo difficult. It is making me panic.

They are pretty hard, although I think they are meant to be tricky. Just because they're hard doesn't mean that you won't do well. Just think, everyone is in the same boat. Chemistry is my strongest subject, and I still find the papers hard. Paper 3 is synoptic, so I think its designed to pull different areas together, and see how you can apply your knowledge.

Reply 8

Abi_rlk

I just find that the answers are really specific. I feel like I've written the right answer and I speak to my tutor and it would work but it's not the answer on the mark scheme

Reply 9

green505

Has anyone got the set 1 paper?

Reply 10

AftabGujral

These two videos might be useful, if you haven't seen them already

https://www.youtube.com/watch?v=4cqjGlTxhDE

https://www.youtube.com/watch?v=GPLNUobTwB4

via MaChemGuy.

Reply 11

Uvuwewewe

what do you guys reckon the grade boundaries for paper 1 and 2 be for an A. like 75 on paper 1 and 73 on paper 2?

Reply 12

Kiki99

Original post by green505

Does anyone else find the paper 3 really hard. I have done the sample papers and have found them soooo difficult. It is making me panic.

Yes i agree! i find it difficult to anticipate what the markscheme answer wants us to write! I find suggesting structures for unfamiliar organic cyclic molecules very difficult!!

Reply 13

Kiki99

Original post by Uvuwewewe

what do you guys reckon the grade boundaries for paper 1 and 2 be for an A. like 75 on paper 1 and 73 on paper 2?

Hey I reckon paper 1 grade boundaries for an A probably similiar to last year, maybe a little higher as this paper contained no nasty surprises? But organic paper 2 on the other hand, i feel like they have to be lower than last year?

Reply 14

Kiki99

Original post by green505

Has anyone got the set 1 paper?

You can find if on My physics and maths tutor

Reply 15

Kiki99

Original post by Abi_rlk

I just find that the answers are really specific. I feel like I've written the right answer and I speak to my tutor and it would work but it's not the answer on the mark scheme

Literally!! i find this exact same issue. Also because theres limited resources its hard to gauge what the markscheme answer wants us to write? Have you done the Unifiying concepts practice questions in the back of the OCR textbook?

Reply 16

Kiki99

Original post by Parmaar

I'm in same boat as you except I found both hard but what you reckon will come up

Potential topics

Buffers calculations
- Potential Y=Mx + C format of the Gibbs expression. Make sure you - - - know how to re-arrange gibbs equation or memorise it!
TLC plate practical description
drawing labelled distillation apparatus, unlikely now as reflux came up in p2.
Relative rates of hydrolysis experiment with haloalkanes. (Lower the C-Halogen enthalpy, faster the rate of hydrolysis.
Questions on how to minimise percentage errors. Eg use a larger mass/volume. Make sure you explain this quantiatatvely. eg, double in mass will halve the percentage error.
Mean titre calculation?
Suggest the structure of some ****ing random organic cyclic alien molecule that nobody can do.
Minimising errors due to heat loss in calorimetry? Eg use of draught screens.
Sources of error in calorimetry, eg heat loss to surroundings, evaporation of fuel from wick, incomplete combustion resulting in a less exothermic value of DeltacH.

A2 organic
Filtration under reduced pressure/recrystallisation/mp determination.
HNMR CNMR again
Mass spec/IR spec

AS organic
radical substitution mechanisms + limitations of this in obtaining a pure product (mixuture of susbtituted products formed)

A2 physical
Feasibility linked to both DG and redox electode potentials
constucting redox equations
balancing redox equations
PH titration curves and neutralisation curves
How Kw changes with temperature, leading to different "neutral PH"
Endothermic dissociation of water
Trends in ionisation energies
Deffo transition metal elements

Module 2
Hydrgoen bonding
IMFs
shapes

Reply 17

Alizarinn

How has everyone learnt the transition metal reactions? I'm really struggling to get them down

Reply 18

DODGY MO

does any one have the 2017 chemsitry paper A

Reply 19

hannah2459

In the textbook the mass of the solid in enthalpy changes of solution calculations is included (page 253-254), but in one of the set papers they didn't and i am not sure whether to just use the mass of the water or whether to include the solid?