Multiple Choice (2 Viewers)

[Fizzy_Cyst]

Sorry for the pretty poor scan quality

View attachment Chem 2015 MC.pdf

 

[diladial]

thank you kind sir

 

[Librah]

1. B 2. D 3. B (I think) 4. C 5. A 6. B 7. B 8. C 9. C 10. A (D isn't balanced?) 11. D (maybe B) 12.A 13. B 14. D 15. A(i forgot what BOD is, but looks like A) 16. C 17. D 18. A 19. C 20. D

Haven't double checked.

 

[I97]

I agree with the above so hopefully thats 20/20 for me, but now after reading 18 again i get why some others suspect it might be C. But still i think it is referring to the pond that was initially being analysed rather than contaminated site so im still thinking its A.

 

[Librah]

Well it says of "THE pond water." So i'm assuming we're studying just that pond in the contamination site.

 

[Khan.Paki]

1. B 2. D 3. B (I think) 4. C 5. A 6. B 7. B 8. C 9. C 10. A (D isn't balanced?) 11. D 12.A 13. B 14. D 15. A(i forgot what BOD is, but looks like A) 16. C 17. D 18. A 19. C 20. D

Haven't double checked.

Got the same answers as you!!

 

[Librah]

Well this years MC was a dud.

 

[HecticLad]

1. B 2. D 3. B (I think) 4. C 5. A 6. B 7. B 8. C 9. C 10. A (D isn't balanced?) 11. D 12.A 13. B 14. D 15. A(i forgot what BOD is, but looks like A) 16. C 17. D 18. A 19. C 20. D

Haven't double checked.

seems right to me, 18/20 id get

 

[el_manu]

Well this years MC was a dud.

i literally did it really quickly in the last 5 minutes, and judging by your answers i got 18/20 (i was going so quickly i didn't see that the incomplete combustion choice D wasnt balanced, and i didn't have enough time to work out the lead concentration one -> didnt even attempt it)

 

[Librah]

i literally did it really quickly and judging by your answers i got 18/20 (i was going so quickly i didn't see that the incomplete combustion choice D wasnt balanced, and i didn't have enough time to work out the lead concentration one -> didnt even attempt it)

lead ion conc is just 0.13/MM(lead chloride) divided by 0.05 lmao

 

[Bozzin8R]

I had the incomplete combustion as D - dunno if it will be marked wrong because its not balanced?
I had the water quality one as C, simply because 400 NTU for turbidity is irrationally high, like that's insane when 20 NTU is considered a high value.

Other than that, agree with your choices - I'm pretty sure the pond question 18 was A, repeating from the same pond seems the more logical answer.

 

[el_manu]

lead ion conc is just 0.13/MM(lead chloride) divided by 0.05 lmao

shit. gave away a free mark,

 

[kawaiipotato]

lead ion conc is just 0.13/MM(lead chloride) divided by 0.05 lmao

What I did this and got like 9.35 x 10^-3
Lol nvm read it wrong it is C

 

[Librah]

OK for q11, answer might be B after actually having a think about it. If you consider something like say Cellulose, OH-(C6H10O5)-OH -> (C6H10O5)n +h20

 

[IamKirby]

OK for q11, answer might be B after actually having a think about it. If you consider something like say Cellulose, OH-(C6H10O5)-OH -> (C6H10O5)n +h20

I don't quite understand how this would work since B is implying that it was just a reaction between the two monomers, not the formation of a polymer? That's just how it appears to me. Even though I see how D might not make sense also.

 

[Librah]

I don't quite understand how this would work since B is implying that it was just a reaction between the two monomers, not the formation of a polymer? That's just how it appears to me. Even though I see how D might not make sense also.

Technically both B and D are wrong, but i think they'd accept D as more correct since it has repeated sub units, so i dunno. I didn't think it was B because it didn't have repeated sub units, which i believe is in the definition of a polymer.

 

[Khan.Paki]

B is not a polymer, so that can't be right. The presence of brackets indicates an infinite chain, hence "condensation polymer", it has to be D, shouldn't it?

 

[IamKirby]

I had the incomplete combustion as D - dunno if it will be marked wrong because its not balanced?
I had the water quality one as C, simply because 400 NTU for turbidity is irrationally high, like that's insane when 20 NTU is considered a high value.

Other than that, agree with your choices - I'm pretty sure the pond question 18 was A, repeating from the same pond seems the more logical answer.

If you look at turbidity standards online you'll see that 400 NTU is actually not that high. Also 5 NTU is amazingly clear for where a river meets the ocean.

Edit: Changed my mind, 400NTU is really turbid.

 

[IamKirby]

Technically both B and D are wrong, but i think they'd accept D as more correct since it has repeated sub units, so i dunno.

Yeah i think it might just be a case of 'we screwed up', whichever is closest to being right which I'd say is D.

 

[monopoly73]

for the one about the correct equation for the incomplete combustion of the fuel i put A becasue D wasn't the balanced, not sure though.. other than that i think i could get 18/20 for multiple choice which is way better than bio