Comparison of Multiple-Choice Answers (1 Viewer)

[CheekyPunk]

9 isnt B, because if you have say, a diprotic acid, or even a weak acid, the same amount of moles wont mean that all the H+ of OH- ions have reacted.
Say with sulfuric acid and sodium hydroxide. you can add the same amount of moles, however sulfuric acid will donate twice as many H+ ions. Thus, the equivalence point - where the indicator changes, is when equal amounts on H+ and OH- ions have reacted.

And 10 is C. It doesnt matter if it goes to one mole after. The equations are not in quantities, they are in ratios.
How much phosphoric acid was produced in the first reaction? about .02M
'What volume of NaOH would be required to neutralise all the phosphoric acid produced?"
All the phosphoric acid is all .02M of phosphoric acid. You dont halve it.

 

[lauranoble]

of course... i dont know what on earth i was actually thinking... seems like such a stupid mistake thanks !

 

[Benmc]

Wow....my morale has dropped.

How did people get 4?????

I did 0.300 x (4.18x10^3) x 20.5.......

WHy did i get B??? WTF???

 

[Kyroth***]

Judging by the responses here I think I got 10/15 for the mc. It's decent for me (better than the trial)... but looking through it now I can see that there ware too many small mistaakes. oh well, never again.

 

[ringout13]

OK, here's mine with a little analysis:
1. C (Catalytic Cracking... duh... no alliteration intended)
2. A (Obvious)
3. B (Other choices have unstable one; stable H is 1,1)
4. C (Calculate it)
5. B (only 4 isomers guys: 1,1; 1,2; 1,3; 2,2 - the others are mirror of those)
6. B (Condensation polymerisation so don't forget to minus the atomic weight 4 water molecules - the problem I can see here is only if what they mean that the 5 glucose form ring shapes polymer which in that case would be A; but I think B is the correct one because it is straight)
7. A (Sweet, eh?)
8. B (HCl is strong and will always be strong, it is just more dilute therefore lower concentration then acetic acid)
9. C (Can be B, I thought I saw this question before but I forgot)
10. B (That is only one mole of phosporic acid on the second equation guys)
11. C (A is Davy, B and D aren't those for Bronsted-Lowry)
12. A (Because the others are incorrect)
13. D (What an easy one)
14. D (Odd one out. 3 significant figures)
15. A (Pressure increases, yield increases; temperature increases, yield decreases)

haha i love this guy, i got 10/15 now!

i knew 10 was b, haah it has to be 0.10, has to be!
your a champ, everyone disagrees but your a geek so your correct, yeah!

 

[hmpfsie]

does anyone by any chance have a copy of the multiple choice questions that they could kindly post up?

 

[CheekyPunk]

Lol.. 10 is not B.
read what i said just before...
The student made .02Moles of phosphoric acid. Then the questions asks what volume of NaOH is needed to neutralise all of the phosphoric acid.
How much phosphoric acid was produced? 0.02 Moles. So that is the value of moles of the acid you use for the second equation. If you half that value, you have only neutralised half the phosphoric acid you produced.

 

[angmor]

10 IS NOT B. for the love of God.

ill post up the 'correct' answers, that is, the GENERAL consensus of this forum.

1C
2A
3B
4C
5B
6D
7A
8B
9B
10A
11A
12A
13D
14C
15A
____

 

[Benmc]

How did people get Question 4????
I thought it was b....
How did people calculate it???

Cheers

 

[XcarvengerX]

i disagree with 10 and 11...im 100% sure 11 is d
question 10 is two seperate equations i remembered doing this in a past paper.
have a look at question 15 in 2005 hsc... same type of question and you will find yourself incorrect.
its c

10. I see what you mean, but for the 2005 one, the 2MnO(OH)₂ is in solid state which then taken to be dissolved. I don't know. I will check with my teacher later. EDIT: Ok, I got it. It is C.
11. Ok, maybe D. I admit I chose C because there is a H⁺ there.
Arrhenius' definition is that when acid dissociates, it will produce H⁺ whereas base will produce OH^- .
However, at Arrhenius time, they only know "dissociation", not "ionisation", according to today's accepted meaning.
And also, don't we use conjugate acid/base to show some acids are strong and others are weak?

I GOT THE EXACT SAME AS YOU..!!! are you good at chem.. coz if u are then I GOT 15/15 haha.. relief.. coz i didnt have time to check over it.. ran outta time which is very unusual!!

haha i love this guy, i got 10/15 now!

i knew 10 was b, haah it has to be 0.10, has to be!
your a champ, everyone disagrees but your a geek so your correct, yeah!

Someone, I mean sometwo agree with me... yay

How did people get Question 4????
I thought it was b....
How did people calculate it???

After you find q in kJ (which is B), then you divided that with number of ethanol used (difference in mass of burner) and multiply by Molar mass of ethanol (46.1).

 

[CheekyPunk]

I think 11 is D, because conductivity is related to how many ions there are. Less ions means less conductive, and he would notice that the less conductive acids were weaker.
Did they even have pH back then? =P

Just for the record, i got both 10 and 11 wrong xD also 14 =/ so only 12/15

 

[arkanisw]

10 IS NOT B. for the love of God.

ill post up the 'correct' answers, that is, the GENERAL consensus of this forum.

1C
2A
3B
4C
5B
6D
7A
8B
9B
10A
11A
12A
13D
14C
15A
____

For the love of God this is the general consenus? the first one posted was perfectly correct except for arguable question 11 which i think is D as well.


this is how i settled question 11:

it's not A, tats Davy, not B, tats Bronsted Lowrey (jsut check txtbk, conquering chemistry), it's C or D

which sounds good, arrhenius said acidity is ionizable h in water.

it's not C coz it's absurd to think pH=-log[H], is a DISCOVERY rather than a definition.

this is really deductive approach. one could really think of it as
"Acid contain ionizable hydrogen ion in water" as Arrhenius definition

D cuts it because those which ionize completely are strong, those incompletely are weak.

but i cant be sure, otherwise the others are good from the first one, which was:

1)C
2)A
3)B
4)C
5)B
6)B
7)A
8)B
9)C (not B, as it had been said, think diprotic!)
10)C (for the love of God, it's C, those who get B got confused by the change in the two equations, the H3PO4 became halved, the simple explanation is that the equation represents RATIO of moles, not exact numbers)
11)D, as explained, though i am not sure
12)A
13)D
14)D (LOL for the Love of God htis one was funny, i chose D immediately without even calculating, those ppl at HSC have a poor sense of trickery, they obviously want to trick the people who will get 0.39075 by simply adding and dividing without the outlier, those who doesnt no ur result is as accurate as ur least accurate data, which was 3 dp, so i knew i just have to round 0.39075 off and bingo it was at option D)
15)A


Edit: typo, 6 should be B

 

[ringout13]

For the love of God this is the general consenus? the first one posted was perfectly correct except for arguable question 11 which i think is D as well.


this is how i settled question 11:

it's not A, tats Davy, not B, tats Bronsted Lowrey (jsut check txtbk, conquering chemistry), it's C or D

which sounds good, arrhenius said acidity is ionizable h in water.

it's not C coz it's absurd to think pH=-log[H], is a DISCOVERY rather than a definition.

this is really deductive approach. one could really think of it as
"Acid contain ionizable hydrogen ion in water" as Arrhenius definition

D cuts it because those which ionize completely are strong, those incompletely are weak.

but i cant be sure, otherwise the others are good from the first one, which was:

1)C
2)A
3)B
4)C
5)B
6)D
7)A
8)B
9)C (not B, as it had been said, think diprotic!)
10)C (for the love of God, it's C, those who get B got confused by the change in the two equations, the H3PO4 became halved, the simple explanation is that the equation represents RATIO of moles, not exact numbers)
11)D, as explained, though i am not sure
12)A
13)D
14)D (LOL for the Love of God htis one was funny, i chose D immediately without even calculating, those ppl at HSC have a poor sense of trickery, they obviously want to trick the people who will get 0.39075 by simply adding and dividing without the outlier, those who doesnt no ur result is as accurate as ur least accurate data, which was 3 dp, so i knew i just have to round 0.39075 off and bingo it was at option D)
15)A

Lets all bow to JESUS
He thinks hes pretty good.

 

[arkanisw]

Lets all bow to JESUS
He thinks hes pretty good.

LOL@joke, QQ more

 

[XcarvengerX]

Don't make this thread become a house of lies...
Here are the correct answers for multiple choice section of 2006 HSC Chemistry:
1. C
2. A
3. B
4. C
5. B
6. B
7. A
8. B
9. C
10. C
11. D
12. A
13. D
14. D
15. A

Use this to mark yours if you are desperate and post your result here. If there are any problems, post it here. Note that everything has been explained throughout this thread, so please read it first before asking any questions.

Personal note: I got 13/15 which is way better than trial 11/15.

 

[yellow103]

Look i thought about question 11 alot and i think is C
because 1. HE definitly proposed that ACIDS dissociates to produce H+ ions which is what gives the acidic nature THUS making C) a correct statement. Its definitly not Wrong as its in all textbooks

D however, said it explained why acids are strong and weak.
FIRST - NO textbooks actually made this point
SECOND - No textbooks gave any clue that people at the time Puzzled over or Questioned weak and strong nature of acids. WE dont know if they even know about weak or strong acids or moles. It did not STATE any of this in ANY text book.

SO therefore D could be right but we are not taught this in textbooks HOWEVER
C) is definitly RIGHT as it improves upon Davy's Theory of Replaceable hydrogen

however BOS might ignore all this and D could be correct answer which in this case i will complain to the senior marker of chemistry (his my tutor ^^) about this

 

[sando]

i got 10/15 from the above post.

not bad.. i got 3/15 for trial lol

 

[Mystic Crusader]

My answers as follows:
1. C
2. A
3. B
4. C
5. D
6. D
7. A
8. B
9. C
10. A
11. C
12. A
13. D
14. C
15. A

 

[XcarvengerX]

Look i thought about question 11 alot and i think is C
because 1. HE definitly proposed that ACIDS dissociates to produce H+ ions which is what gives the acidic nature THUS making C) a correct statement. Its definitly not Wrong as its in all textbooks

D however, said it explained why acids are strong and weak.
FIRST - NO textbooks actually made this point
SECOND - No textbooks gave any clue that people at the time Puzzled over or Questioned weak and strong nature of acids. WE dont know if they even know about weak or strong acids or moles. It did not STATE any of this in ANY text book.

SO therefore D could be right but we are not taught this in textbooks HOWEVER
C) is definitly RIGHT as it improves upon Davy's Theory of Replaceable hydrogen

however BOS might ignore all this and D could be correct answer which in this case i will complain to the senior marker of chemistry (his my tutor ^^) about this

OK. I also chose C but I chose C only because there is a H⁺ there.
According to some people above, pH system has not been invented at that time (I think the pH concept was first introduced in early 1900), so that is the problem with C. How can you show a relationship with something that has not been implemented yet? And D, as you said, is not incorrect either, so D is the most correct answer.

 

[suchet_i]

number 14 is D coz we are always meant to answer a question in the same decimal places as stated in the question. sorry if this has already been mentioned
got 14/15