HSC Chemistry Exam Solutions / Thoughts (6 Viewers)

[worldno17]

What did people put for last mcq? Also, i got effective for Cu2+, ineffective for Pb2+.

 

[AHafza]

What did people put for last mcq? I got effective for Cu2+, ineffective for Pb2+.

Last question of multiple choice ?

 

[flowerp]

Oxidation and addition of sodium carbonate powder. Whichever bubbles contains aldehyde as it wouldve oxidised to a carboxyllic acid releasing co2

I remembered the carbonated method after I wrote my response but didn’t have time to change my answer - ugghh hopefully litmus will still be accepted!

 

[worldno17]

Last question of multiple choice ?

Yep sorry, edited my previous post.

 

[flowerp]

Last question of multiple choice ?

I got C 0.48%

 

[AHafza]

Yep sorry, edited my previous post.

I got 1%

 

[Arrowshaft]

I got C 0.48%

Same

 

[jazz519]

Can u use blue litmus paper? I was initially going to put co2 effervescence with carbonate but changed it last minute.

Maybe they will allow you to use that as a test, but technically in real life the litmus paper would be useless because for an oxidation reaction you use the strong oxidising agent which is acidified. So the reason it might change to red is because you just added the acidified oxidising agent already. Not sure how much they want you to actually think about things but using litmus paper is a valid test for an acid but maybe not in this situation

 

[worldno17]

Same, I got C for last mcq.
People on HSC fb discussion group are saying that there was a typo for the ethanol heat of combustion question??

 

[Arrowshaft]

What did people put for last mcq? Also, i got effective for Cu2+, ineffective for Pb2+.

What values did you get? Because i got ineffective for both

 

[Balajanovski]

Easy paper. Good fun. Lots of calculations and the reaction pathways was fun.
What did you guys write for the identification tests for the last question?

 

[worldno17]

What values did you get? Because i got ineffective for both

Umm cannot recall for Cu but got 1.9 mg L-1 for Pb.

 

[Arrowshaft]

Same, I got C for last mcq.
People on HSC fb discussion group are saying that there was a typo for the ethanol heat of combustion question??

na dont think so, i got like -600 smth

 

[Balajanovski]

What values did you get? Because i got ineffective for both

I think you're likely wrong Arrowshaft. I don't remember my values but I got effective for Cu ineffective for Pb as well. Same for everyone at my school that I talked to.

 

[worldno17]

na dont think so, i got like -600 smth

Same! I expressed it as positive though - thought molar heat of combustion is usually expressed positive as a convention?

 

[Arrowshaft]

I think you're likely wrong Arrowshaft. I don't remember my values but I got effective for Cu ineffective for Pb as well. Same for everyone at my school that I talked to.

Hmm, yeah probs. Hopefully dont lose too many marks then

 

[Arrowshaft]

I also recall 1.9 for Pb, mustve messed up Cu

 

[flowerp]

Same! I expressed it as positive though - thought molar heat of combustion is usually expressed positive as a convention?

Me three! I got somewhere around 628KJ/mol

 

[AHafza]

i regret switching from co2 test to litmus. Lol

 

[jazz519]

i regret switching from co2 test to litmus. Lol

You will probably be fine. I doubt they are thinking that hard about real life application in HSC, otherwise half the stuff would be wrong lol