SUGGESTED ANSWERS!!!

[polkadot]

So do you think OH-(aq) + HCl(aq) ---> H20(l) + Cl- (aq) would be acceptable for question 8a? (Don't ask me why i decided to write half an ionic equation -.-)

[yamnush2020]

ds anyone have the question n answer booklet for tdays exam??

[Bhootnike]

ds anyone have the question n answer booklet for tdays exam??

questions are : VCAA 2012 Chemistry Unit 3 Exam Discussion

[Yellow_]

Isn't MC
i had

5) A
12) C?

[vagrantshades]

Isn't MC 5 A)?

I put the option that had I and III only (this is the amino acid question right?). It couldn't be II because that would state that hydrogen bonds could occur between any C=O and N-H functional groups, and I found some amino acids that had those functional groups in their side chains.

How much do you think we could have dropped on this exam to be still in the running for a 50? I think I've stuffed up on one question, that stupid solubility one. It was annoying because technically some PbI2 was still dissolved in solution, though it's correct to state you can't really calculate because you don't know how much KI was added. Dumb question.

[Tonychet2]

Isn't MC 5 A)?

I put the option that had I and III only (this is the amino acid question right?). It couldn't be II because that would state that hydrogen bonds could occur between any C=O and N-H functional groups, and I found some amino acids that had those functional groups in their side chains.

How much do you think we could have dropped on this exam to be still in the running for a 50? I think I've stuffed up on one question, that stupid solubility one. It was annoying because technically some PbI2 was still dissolved in solution, though it's correct to state you can't really calculate because you don't know how much KI was added. Dumb question.

i put down A personally also, but everyone seemed to agree with D so in these i put D

[Yellow_]

wb 12, i thought retention time stays the same



must have read it wrong
my bad

Q 5...
i really think it's A
though it's a bit ambigous as they can be in z side chains, maybe 2 correct sols?

[Bhootnike]

Isn't MC
i had

5) A
12) C?

Isn't MC 5 A)?

I put the option that had I and III only (this is the amino acid question right?). It couldn't be II because that would state that hydrogen bonds could occur between any C=O and N-H functional groups, and I found some amino acids that had those functional groups in their side chains.

How much do you think we could have dropped on this exam to be still in the running for a 50? I think I've stuffed up on one question, that stupid solubility one. It was annoying because technically some PbI2 was still dissolved in solution, though it's correct to state you can't really calculate because you don't know how much KI was added. Dumb question.

it was secondary structure, not tertiary so z-group interactions dont matter i think.
secondary structure is the hydrogen bonding between amide groups. so i think B was right.

12 was defintely C!

[charmanderp]

Isn't MC
i had

5) A
12) C?

12 was C. 5 was D because it's not technically false to say that the secondary structure involves hydrogen bonds between N-H and C-O groups. Because that is the case. If it had said that it involved hydrogen bonds between all N-H and C-O that would be untrue.

[vagrantshades]

wb 12, i thought retention time stays the same



must have read it wrong
my bad

Q 5...
i really think it's A
though it's a bit ambigous as they can be in z side chains, maybe 2 correct sols?

I think the option should have said C=O and N-H functional groups in the peptide linkage or something. A should definitely be correct, not sure if they should accept D though.

[Yellow_]

gg

[saltandpepper_160511]

Would the answer for Question 1 a i be galactose because of the rearrangement of carbon fours hydroxyl group from positioned down to a up position?   

[vagrantshades]

Isn't MC
i had

5) A
12) C?

12 was C. 5 was D because it's not technically false to say that the secondary structure involves hydrogen bonds between N-H and C-O groups. Because that is the case. If it had said that it involved hydrogen bonds between all N-H and C-O that would be untrue.

It would be false, because the secondary structure isn't maintained by hydrogen bonds between N-H and C-O groups in the side chains. By saying between N-H and C-O groups, it still includes those side chains. So I guess they might have to accept two answers then.

[Bhootnike]

wb 12, i thought retention time stays the same



must have read it wrong
my bad

Q 5...
i really think it's A
though it's a bit ambigous as they can be in z side chains, maybe 2 correct sols?

I think the option should have said C=O and N-H functional groups in the peptide linkage or something. A should definitely be correct, not sure if they should accept D though.

It said ' in the secondary structure...'
so that would automatically imply hydrogen bonding b/w amide groups! which i believe option II satisfies?

[jasoN-]

Would the answer for Question 1 a i be galactose because of the rearrangement of carbon fours hydroxyl group from positioned down to a up position?   

No, cellulose is comprised of glucose monomers.
The reason why the hydroxyl group is down to up is because cellulose is contains beta-1,4-glycosidic linkages, so alternating glucose molecules would be flipped (look at the ring Oxygen, you can see how it flips as well)