Suggested Answers - Illuminati

[Tonychet2]

Also q4. bi) and bii) don't they round up to 8.4*10^-4 M

I got 8.4 too, but wasn't it to the power of -5? My memory fails me.

Also, what would 7 dropped on the midyear and 1 dropped today get me, with 100% SACs?

46-48

[oneoneoneone]

Wasn't the cutoff for midyear about 7 marks off though? I doubt you could get a 45+ with a Low High High A+

[WhoTookMyUsername]

i think you could touch 45/46 possibly, but nothing higher, realistically 43-46 probs?

[charmanderp]

  b) The value in the databook refers to the reaction of methanol in which the co-efficient in front of methanol is 1. There is 2 in the equation in part a.ii. and hence the value is approximately twice as large.

I'm not sure about this one. It specifies the value for delta H calculated using the enthalpy of combustion, and given that we had to multiply it by 2 to get the mark for the previous answer I think this was already assumed. If this is right I think that question's a bit silly.

What if we wrote that they were different because the experiment we used might not have occurred at SLC, or the methanol sample was impure?

Damn stupid mistakes on the midyear ):

[DJing]

If I lost 4 marks in the mid-year and 3-4 in today's paper and did well in my SACs what study score can I expect (I know it depends but I just want a rough estimate)? Thanks.

like 45-48 easy

:O Really? woah

[Tonychet2]

how is question 15 mc D?

[oneoneoneone]

You need to add the 33kJ required to convert the water from liquid to gas form.

[Tonychet2]

You need to add the 33kJ required to convert the water from liquid to gas form.

what 33kj? where do u get that value from

[dfgjgddjidfg]

it says 55kj was needed to convert water from 20-100 degrees and then it says how much energy needed to raise 100g from 0-100 degrees. dodgy question

[davo_10]

For Q9 on the multi-choice

Isn't the answer A because the K value is higher than the equilibrium value, so the forward rate is greater than the backward rate?

[dfgjgddjidfg]

what could i get with A sacs ranked two in medium cohort. High A exam 1 low A+ exam 2?

[pezz619]

Nah it says 54kj per mole to convert liquid water to steam at 100
So you have to calculate energy from 20-100 and then liquid water to steam at 100

[baddin]

Was this exam worth 72 marks? I dont remember now

[illuminati]

For Q9 on the multi-choice

Isn't the answer A because the K value is higher than the equilibrium value, so the forward rate is greater than the backward rate?

The concentration fraction was greater than K, so backwards > forwards.

[Tonychet2]

  b) The value in the databook refers to the reaction of methanol in which the co-efficient in front of methanol is 1. There is 2 in the equation in part a.ii. and hence the value is approximately twice as large.

I'm not sure about this one. It specifies the value for delta H calculated using the enthalpy of combustion, and given that we had to multiply it by 2 to get the mark for the previous answer I think this was already assumed. If this is right I think that question's a bit silly.

What if we wrote that they were different because the experiment we used might not have occurred at SLC, or the methanol sample was impure?

Damn stupid mistakes on the midyear ):

isnt the answer because some heat energy is lost from poor insulation? therefore the temperature increases less and the calculated delta H value of methanol is lower