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

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Reply 60

bran747

Original post

by Darcey08374

I said put a lid on the cup 😭

Yeah I put a lid on a cup while stiring

Reply 61

chemmlover4eva

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

chemmlover4eva

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

sfuoieoiefhse

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

Mils12

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

Reply 65

hwhejfjejsjx

Original post

by Mils12

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

i got ethyl benzoate

Reply 66

hwhejfjejsjx

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

hwhejfjejsjx

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

Reply 68

hwhejfjejsjx

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

Reply 69

Mils12

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

Darcey08374

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

Mils12

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

Mils12

Original post

by Darcey08374

What was the actual figure for the % uncertainty

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

Reply 73

katiesykess

Original post

by Mils12

Yeah 4 marker +24.something to 3sf

what was this question i don’t remember it haha

Reply 74

bran747

Original post

by veuofn

which was the conjugated acid

I put h3po4 i think

Reply 75

chemmlover4eva

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