multiple choice...WTF? (2 Viewers)

~ ReNcH ~ · Nov 2, 2005

xrtzx said:
and the buffer q

I think I got that one right...D

richz · Nov 2, 2005

o sorry, i cudnt count

serge · Nov 2, 2005

Dumsum said:
I got exactly the same as you. Go us

Except I just realised that 14 is D

yay, 100% MC

n00b · Nov 2, 2005

yes it is

the answer to 1 is without a doubt b, an unstable nucleus due to it being too heavy is just something you should know.

sausage roll · Nov 2, 2005

Did anyone find the heat of combustion question hard? I picked B

falltopieces · Nov 2, 2005

sausage roll said:
Did anyone find the heat of combustion question hard? I picked B

I picked B as well.

Um...how about the AAS question. Which one is the right answer?

richz · Nov 2, 2005

metal ion... ie calcium

falltopieces · Nov 2, 2005

xrtzx said:
metal ion... ie calcium

glad got that one correct

Ethyl pentanoate is used as food flavouring right?

Captain Gh3y · Nov 2, 2005

serge said:
yay, 100% MC

Me too, then.
*hi five*

laserbrainz · Nov 2, 2005

yeah, I think the ester (Ethyl pentanoate) is pineapple flavouring, but not certain on that. It is a flavour though (took back my textbook). Any of you 100% MC'ers know?

richz · Nov 2, 2005

Captain Gh3y said:
Me too, then.
*hi five*

dang.. i think i got 12,

. very disappointed, didnt read the qs

falltopieces · Nov 2, 2005

laserbrainz said:
yeah, I think the ester is pineapple flavouring, but not certain on that (took back my textbook)

yup i guess it's the pineapple flavouring

justchillin · Nov 2, 2005

I know 1 is B...but the defonition of an atom is something neutral isnt it...so D is also correct, if they had said "ion" then yes wrong, but they said atom...hence number of protons = number of electrons. ie excess of electrons = unbalanced ration neutrons

rotons, ie radioactive. Someone pro ve me wrong...though I know its not the most correct.,..haha

~ ReNcH ~ · Nov 2, 2005

justchillin said:
I know 1 is B...but the defonition of an atom is something neutral isnt it...so D is also correct, if they had said "ion" then yes wrong, but they said atom...hence number of protons = number of electrons. ie excess of electrons = unbalanced ration neutronsrotons, ie radioactive. Someone pro ve me wrong...though I know its not the most correct.,..haha

That reasononing is what made me consider D, but B still seems more correct even though it's not strictly "correct". Meh, I just have my fingers crossed that BOS also thinks the answer is B.

~ ReNcH ~ · Nov 2, 2005

Captain Gh3y said:
Me too, then.
*hi five*

lol...14/15 for me then. Damn my stupidity for Q5

gjl · Nov 2, 2005

argggggg

got Q 4 WRONG!!!!!!!!
sooooooooooo dumb, didnt read the question properly

punki_pixi · Nov 2, 2005

For 1 i had B. I was going to put D because it said isotope and that has different number of neutrons than the normal atom doesnt it? and I was thinking the number of electrons equals number of protons. But it could be an ion couldn't it? Well it also said what condition produces... and if there are too many protons and neutrons this would produce an isotope through decay, so I ended up with B.

I had H2So4 for the buffer thing since its diprotic... the CH3COOH can only lose its end hydrogen atom can't it? I'm just hoping its right but if not oh well...

~ ReNcH ~ · Nov 2, 2005

punki_pixi said:
For 1 i had B. I was going to put D because it said isotope and that has different number of neutrons than the normal atom doesnt it? and I was thinking the number of electrons equals number of protons. But it could be an ion couldn't it? Well it also said what condition produces... and if there are too many protons and neutrons this would produce an isotope through decay, so I ended up with B.

I had H2So4 for the buffer thing since its diprotic... the CH3COOH can only lose its end hydrogen atom can't it? I'm just hoping its right but if not oh well...

That buffer one:

The acetic acid-acetate buffer system can act as a buffer which suggests that acetic acid in the saliva of caries free subjects may diffuse into plaque to act as an effective buffer to counteract the destructive effects of lactic acid.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9462046&dopt=Abstract

Just a random Google search brought this up, so I'm guessing D is correct, whether or not the others are correct or incorrect.

mellowdee · Nov 2, 2005

yeh.. this is how i approached the question..
*buffers comprise of a weak acid and its conjugate base, so there goes A and C
*B is wrong cuz it isn't even the conjugate
*thus the answer is D

buffers dun hav to be diprotic

Captain Gh3y · Nov 2, 2005

~ ReNcH ~ said:
That buffer one:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9462046&dopt=Abstract

Just a random Google search brought this up, so I'm guessing D is correct, whether or not the others are correct or incorrect.

D is correct because:

HCl is a strong acid, therefore its conjugate is an extremely weak base, too weak to actually act as a base.

H2SO4/HSO4 are an acid/base conjugate pair, but HSO4 is amphiprotic and is not guaranteed to act as a base.

H2PO4/PO4 are not a conjugate acid/base pair,

so that leaves only acetic acid/acetate ions, and of the 3 conjugate pairs, acetate ions are easily the strongest base.

multiple choice...WTF? (2 Viewers)

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