Exam 2 Thoughts

[melodrama]

Yay/nay?

Easier BY FAR than the 06 paper. That damned paper sent me into a frenzied panic this morning.

[melodrama]

My answers:

BDCDBDABADACBBACCDBC

Mg, U, Al, B, O, Sn
Mass spectrometer
113, 113, 171
3, 7
Tl
279Rg

[He]2s2/2p2, [Ar]3d6/4s2, [Ar]3d5
Group 6 Period 5

C6H12O6
Cwhatever+12O2 -> 12CO2+11H2O
-5632kJmol^-1 (x2 because maltose has two glucoses)
30

goes to C17H35COOCH3 + H2O (sorry, typo)

Z group was CH3
Z2, Z1
Denatured by pH
198
6.69g
19.1g
5.73x10^3kJmol^-1

Platinum
25deg. C
pH 0
Cd (s) increase pH, decrease H+... etc. etc. Cd is oxidised


0.0275 mol
1:1
+1
goes to X2+ + e- -> X+ (apparently it's X3+, with the oxidation state +3)
Cu2+ + 2e- -> Cu
941C
4.8 x 10^-3 mol
9.78 x 10^4Cmol^-1
Cu fell off

[Collin Li]

Anyone got a copy of the exam paper? If someone gets it to me... like now, I could produce solutions before I head off to my chemistry exam.

[kingmar]

Extremely tricky. Simplistic in places, but overall tricky.

BTW, spirited, your "X" thingy is wrong. It's X2+ loses an electron to form X3+.

[cara.mel]

In the 2nd last question, X is losing electrons
X2+ -> X3+ +e-

The last multi choice was worded bad. I put D, because I thought it meant 'the amount of energy in each form turned into electrical'. So in the turbine nearly all of the energy -> electrical, but in the coal only a small amount turns into electicity. My chem teacher put C. Meh, don't care any more.

Overall, I thought it was of a good difficulty, so I'm happy with it

[melodrama]

oh yeah. damnnn -2 marks already.

[v2shan]

Extremely tricky. Simplistic in places, but overall tricky.

yeah totally agree, nicely put

[Jasper]

Cu fell off

Oh oh, looks like I missed a question  :?

How many marks was this question worth?

Overall, exam was good, a few tricky multi's but nothing too too bad.

[melodrama]

that's the one where you have to account for the higher F value. don't worry, it was only 1 mark.

[Jasper]

that's the one where you have to account for the higher F value. don't worry, it was only 1 mark.

Oooohh...yeah I did that question, just got a different answer...pphhheeewwwww.

I think I got something like the current was read incorrectly (too high) or something, don't know if it's right though.

[v2shan]

My answers:

Platinum
25deg. C
pH 0
Cd (s) increase pH, decrease H+... etc. etc. Cd is oxidised

i don't get it......can som1 explain why pH =0 pls ?

[winter_89]

standard condition means 1M of H+ , hence 0 pH

[Collin Li]

If anyone has particular concerns on a particular question, if you tell me the question, I can try to help you find the answer.

[bonghead]

i ended up running out of time i had to leave 5 multiple choice answers
Did everyone finish it easily?

[*insert witty name here*]

concentration is 1M
ph = -log [h+]
    = - log 1
    = 0