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OCR A-level Chemistry B (Salters) Paper 1 - 10th June 2025 [Exam Chat]

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Reply 60

Original post
by Darcey08374
I said put a lid on the cup 😭


Yeah I put a lid on a cup while stiring

Reply 61

Original post
by veuofn
for the reduce uncertainty did anyone say more mass, greater mass used

yh thats right, i said use greater mass of ammoniumwhateveritwas as that will increase the temperature change so %uncertainty lower

Reply 62

Original post
by bran747
Yeah I put a lid on a cup while stiring

stiring might be right but it was an endothermic reaction so theres no heat that is lost from surroundings, heat is being taken in? how would a lid help

Reply 63

Original post
by bran747
Yeah I put a lid on a cup while stiring


If you put a lid, the temperature change is smaller, so there is greater % uncertainty

Reply 64

What was the nmr structure, I got phenyl propanoate but some getting ethyl benzoate

Reply 65

Original post
by Mils12
What was the nmr structure, I got phenyl propanoate but some getting ethyl benzoate
i got ethyl benzoate

Reply 66

Original post
by chemmlover4eva
yh thats right, i said use greater mass of ammoniumwhateveritwas as that will increase the temperature change so %uncertainty lower

i just said use a mean was it not talking about temperature not mass?

Reply 67

the 4 marker was PLUS 24. the 1 marker PLUS 25. one was +51? and i dont remember the arhenius one.

Reply 68

The mass was 3.03grams i've just redone it. 3.01 is a rounding error.

Reply 69

Original post
by hwhejfjejsjx
The mass was 3.03grams i've just redone it. 3.01 is a rounding error.
Yeah I remember writing 3 2 times now so I got 3.03 idk why I put 3.01 here

Reply 70

Original post
by hwhejfjejsjx
i just said use a mean was it not talking about temperature not mass?


What was the actual figure for the % uncertainty

Reply 71

Original post
by hwhejfjejsjx
the 4 marker was PLUS 24. the 1 marker PLUS 25. one was +51? and i dont remember the arhenius one.

Yeah 4 marker +24.something to 3sf

Reply 72

Original post
by Darcey08374
What was the actual figure for the % uncertainty

(2*0.5)/whatever change in temp was ?

Reply 73

Original post
by Mils12
Yeah 4 marker +24.something to 3sf


what was this question i don’t remember it haha

Reply 74

Original post
by veuofn
which was the conjugated acid


I put h3po4 i think

Reply 75

Original post
by hwhejfjejsjx
i just said use a mean was it not talking about temperature not mass?

When you increase the mass of the solute, you are essentially adding more solute molecules that need to be dissolved. This means the solution will absorb more energy from the surroundings, so final temp will be lower, so temp change is higher. dividing by a larger number (larger temp change) reduces the % uncertainty, search it up

Reply 76

only 2 marks anyway

Reply 77

Original post
by katiesykess
what was this question i don’t remember it haha

The enthalpy change of solution of ammonium nitrate in water one

Reply 78

Did anyone find the multiple choice tougher than usual

Reply 79

Original post
by Mils12
Did anyone find the multiple choice tougher than usual


Yh some of them were weird