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last SG · 2015-08-19T22:54:00+00:00

Topic : atomic radius Hi! This is from singapore cambridge nov a level exam year 2010,Paper 1 qn 1Qn: which element has the largest atomic radius?BrKKrScSo...

Flying grenade SG

deuterium vs hydrogen leaving group

https://www.quora.com/Why-is-the-deuterium-eliminated-in-this-E2-reaction-instead-of-the-proton-in-the-ACS-study-guide-for-Organic-Chemistry

Flying grenade SG

page 367

for delocalisation of e- into b.ring, the hybridisation of N atom can be , or is, between sp2 and sp3?

or is it must be sp2 like C atom?

Flying grenade SG

page 377

will the Ring in Atropine exhibit aromaticity? it has alternating single and double bonds

if required to draw in exams, can i draw a circle, representing delocalised pi e- cloud, like benzene?

should benzene be included as a functional group, as asked by the qn to name all functional groups present?

thanks

UltimaOnline SG

page 367

for delocalisation of e- into b.ring, the hybridisation of N atom can be , or is, between sp2 and sp3?

or is it must be sp2 like C atom?

Go ask your school teacher or private tutor. Edart sterces.

UltimaOnline SG

page 377

will the Ring in Atropine exhibit aromaticity? it has alternating single and double bonds

if required to draw in exams, can i draw a circle, representing delocalised pi e- cloud, like benzene?

should benzene be included as a functional group, as asked by the qn to name all functional groups present?

thanks

Yes. Yes. Yes.

Flying grenade SG

thanks for yr reply

page 392

Esub of NO2+ to chloromethylbenzene, the NO2 can sub at any position??

Flying grenade SG

does zwitterion only occur at isoelectric points only? or zwitterions occur at any pH, just that the amount of zwitterions at isoelectric points is the greatest?

Flying grenade SG

at isoelectronic point, the zwitterion is the dominant form of the amino acid

UltimaOnline SG

thanks for yr reply

page 392

Esub of NO2+ to chloromethylbenzene, the NO2 can sub at any position??

No. You have to decide for yourself (based on understanding) if CH2Cl is ortho-para or meta director, unlike Singapore JC students (based on blind memorization).

Ask your school teacher or private tutor, move on. Edart sterces.

UltimaOnline SG

does zwitterion only occur at isoelectric points only? or zwitterions occur at any pH, just that the amount of zwitterions at isoelectric points is the greatest?

What do you think? Isn't it obvious?!? (well maybe not to Singapore JC H2 students).

Flying grenade SG

No. You have to decide for yourself (based on understanding) if CH2Cl is ortho-para or meta director, unlike Singapore JC students (based on blind memorization).

Ask your school teacher or private tutor, move on. Edart sterces.

both CH3 and Cl are ortho para directors

now the Cl connected to CH2 and then connected to Benzene. can't figure out overall if CH2Cl is e- donating or withdrawing.

dun think Cl will be that powerful as to manage to withdraw e- from benzene through one CH2 unit.

hence my guess is overall CH2Cl is weakly activating ,and hence act as an ortho para director

UltimaOnline SG

both CH3 and Cl are ortho para directors

now the Cl connected to CH2 and then connected to Benzene. can't figure out overall if CH2Cl is e- donating or withdrawing.

dun think Cl will be that powerful as to manage to withdraw e- from benzene through one CH2 unit.

hence my guess is overall CH2Cl is weakly activating ,and hence act as an ortho para director

Ask your school teacher or private tutor, move on. Edart sterces.

Flying grenade SG

page 453

addition of polar organic solvents will denature proteins

how about inorganic solvents like water?

Flying grenade SG

page 455

part f

so like proteins are soluble in water, and that's about it? wouldn't polar water "interfere with the H bonding between R groups" , as ethanol would?

Flying grenade SG

page 455

example 11.14

what's the first reaction? substitution of Br from H in Alkane?

UltimaOnline SG

page 453

addition of polar organic solvents will denature proteins

how about inorganic solvents like water?

Then you die liao lor. All the proteins in your body kena denature liao.

UltimaOnline SG

page 455

part f

so like proteins are soluble in water, and that's about it? wouldn't polar water "interfere with the H bonding between R groups" , as ethanol would?

It 'interferes' until you get your current desired configuration of proteins, supporting life specifically in aqueous environments only. Billions of years of evolution, yo.

Of course, both Creationism and Darwinism are oversimplified and incomplete. The truth is more akin to Interventionism, and evolution continues hand-in-hand with higher guidance, at all levels. Just as human geneticists would biotechnologically intervene in the genomes of other species for various purposes of genetic modification and even creation, likewise on a macroscopic level across planetary civilizations and beyond.

UltimaOnline SG

page 455

example 11.14

what's the first reaction? substitution of Br from H in Alkane?

Typo error in the reactant. Mixing P4 and Br2 simply generates PBr3 in situ.

Nikkilyx SG

Hi i need some help...

Which of the following will not reduce random errors in your experimental measurements?

a) double the weight of magnesium used to a calorimetry experiment

b) use a thermometer with a smaller scale

c) use activated and finer magnesium granules

d) use a larger calorimeter with the same volume of solution

i am thinking the answer is d since the rest will lead me to a more precise answer

Flying grenade SG

Typo error in the reactant. Mixing P4 and Br2 simply generates PBr3 in situ.

is the reactant CH3CH(OH)COOH?

what does the addn of water H2O do after generating PBr3 in situ ???

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