ocr a f325 revision thread

Will I get the mark

for saying, h2o was not present in rate equation ?

In mark scheme they put TdetaS< DETA G

I put detaG> TdetaS ? is that fine

But It was CH3 CH3 not O O

Good news then! were we given a molar mass? I must have overlooked that entirely.

The equation for the reaction when zinc powder was added was also 2 marks not 1.

Yes, that's fine! And that depends on the question...?

For the delta G, I believe it was 2879 + 298x0.256 = 2955. It was worth at least 2 marks.

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The aluminium ionic equation should be

6H⁺ + 2Al -----> 2Al³⁺+3H2

Also, for the tin and iodine compound reaction - do you think they'll allow the addition of OH^- to the right hand side instead of water?

So

6H⁺ + 5Sn²⁺+2IO3- -------> 5Sn⁴⁺ + I₂ + 6OH^-

I too got this number

Is delta G not Delta H - TDS? (Not add?)

dS was negative, so -TdS was positive; that was the point of why it is never feasible.

Is delta G not Delta H - TDS? (Not add?)

I don't understand your question, perhaps if you rephrase please?

that one was ok, i got 5.1 x 10^16. you knew G was that energy, then divide by delta H to give moles. Then times 44 to get the mass (n = m/mr)

Dw, I was just confused because the before person wrote it as plus; but that's only because I always think of it as minus minus!
(Check delta G on the Mark Scheme!)

Dw, I was just confused because the before person wrote it as plus; but that's only because I always think of it as minus minus!
(Check delta G on the Mark Scheme!)