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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

Your many posts with no question in it is getting increasingly annoying. If there's no question, don't post. If you've a question, phrase it properly.

i am giving the correct corrections. i thought that will be good. for future readers reading cs toh's and george chong's made easy books that could have possibly come across this chem thread.

UltimaOnline SG

i am giving the correct corrections. i thought that will be good. for future readers reading cs toh's and george chong's made easy books that could have possibly come across this chem thread.

Then say so lah. Many of your posts you just type some statements, with no clear question. Annoying coz I dunno if you need me to reply or if you need my help or not. In future, specify with something like : "This post is for information only. Coz I'm a good man who loves to help my fellow JC students." or something to that effect.

Flying grenade SG

Thanks Ultima god! !!

Flying grenade SG

generally, increase in temperature increases solubility of ionic compounds.

page 138 organic made easy book

test for haloalkanes

heat with naoh. cool. acidify with hno3. add agno3.

my friend ask me why need cool in step 2. i dk how to answer.

is it cos temp higher so AgX cannot be precipitated? if we do all steps except/without cooling, when the solution reaches room temperature, will AgX be precipitated?

thanks ultima

UltimaOnline SG

generally, increase in temperature increases solubility of ionic compounds.

page 138 organic made easy book

test for haloalkanes

heat with naoh. cool. acidify with hno3. add agno3.

my friend ask me why need cool in step 2. i dk how to answer.

is it cos temp higher so AgX cannot be precipitated? if we do all steps except/without cooling, when the solution reaches room temperature, will AgX be precipitated?

thanks ultima

Yes. Because higher temperature thermodynamically favors the positive entropy change of (s) --> (aq)

Flying grenade SG

Yes. Because higher temperature thermodynamically favors the positive entropy change of (s) --> (aq)

so can cool before and after , no issue?

UltimaOnline SG

so can cool before and after , no issue?

What did Chan KS write? What did CS Toh write? What do u think? This sort of little KUCING KURAP why don't you have the independence to decide for yourself lah!

Flying grenade SG

thanks god. ks chan org chem book page 195 . found it

thanks !!!

Flying grenade SG

page 196 org made easy book

what is protonated alcohol? can't figure out from the mechanism at btm of page.

for the mechanism at btm of page, shld the arrow from Lone pair of alcohol reach the delta positive O ? it shld right?

many mistakes this book presented, but i learn alot from this book also. still will recommend to jc students.

i dun understand/cant decipher the mechanism in page 196.

can help check and help me improve and correct this, thank you ultima

https://www.dropbox.com/s/2ymnjkasbpi4qtn/20160822_183400.jpg?dl=0

there's also a mechanism for the formation of diethyl ether in here

https://en.m.wikipedia.org/wiki/Ether

dk how reconcile the george chong mechanism on this symmetrical ether

UltimaOnline SG

page 196 org made easy book

what is protonated alcohol? can't figure out from the mechanism at btm of page.

for the mechanism at btm of page, shld the arrow from Lone pair of alcohol reach the delta positive O ? it shld right?

many mistakes this book presented, but i learn alot from this book also. still will recommend to jc students.

i dun understand/cant decipher the mechanism in page 196.

can help check and help me improve and correct this, thank you ultima

https://www.dropbox.com/s/2ymnjkasbpi4qtn/20160822_183400.jpg?dl=0

there's also a mechanism for the formation of diethyl ether in here

https://en.m.wikipedia.org/wiki/Ether

dk how reconcile the george chong mechanism on this symmetrical ether

"What is protonated alcohol?"

-_-" If you don't even know this, how are you gonna sit for your A level exams in 2 months' time? -_-"

George Chong merely left out 1 curved arrow (the elimination of H2O+ as H2O), otherwise the rest of the mechanism is correct. But *you* totally screwed up his mechanism with your erroneous curved arrows.

If you don't understand his mechanism. then you need your school teacher or private tutor to explain the mechanism to you in-person. Move on.

Flying grenade SG

"What is protonated alcohol?"

-_-" If you don't even know this, how are you gonna sit for your A level exams in 2 months' time? -_-"

If you don't understand his mechanism. then you need your school teacher or private tutor to explain the mechanism to you in-person. Move on.

got what is protonated alcohol liao.

ok noted. thanks ultima

Flying grenade SG

posting for info.

https://en.m.wikipedia.org/wiki/Methacrolein

2-Methylprop-2-enal.

interesting structure. contains aldehyde and alkene functional group.

Flying grenade SG

pg 229. George chong writes lonepair on sp3 hybridised orbital of O , again. is this erroneous?

how to tell when O and N is sp2 or sp3 hybridised?

Flying grenade SG

pg 231 top of page i think he meant chromium trioxide, CrO3, instead of dichromate

UltimaOnline SG

pg 229. George chong writes lonepair on sp3 hybridised orbital of O , again. is this erroneous?

how to tell when O and N is sp2 or sp3 hybridised?

Sterces Edart.

Flying grenade SG

page 263 org made easy book

Fact + correction for mistakes

btm of page. 2nd cpd shld be named butan-2-ol. last cpd shld be named 2-methylbutan-2-ol.

UltimaOnline SG

page 263 org made easy book

Fact + correction for mistakes

btm of page. 2nd cpd shld be named butan-2-ol. last cpd shld be named 2-methylbutan-2-ol.

I don't doubt you have good intentions, has it occurred to you publicly pointing out the typos in a book might just annoy the author? And would JC students really take note of each typo error you point out in this thread, excitedly look it up in their book to make the corrections, and each time exclaim, "Thank you Flying Grenade!"?

*shrugs* It's up to you (if you want to continue doing so). (For any action) if you really feel what you're doing is 'right' (in reality there is no absolute right or wrong ; there is only legality, ethics and cosmoethics ; morality is an illusion), ie. if you think it's helpful to others, then you gotta stand by yourself and do what you feel is right. But of course, what's 'right' at one time, may not be always 'right' at other times. What's 'right' for one person may not be 'right' for another (and the same action taken by 2 different individuals may have different karmic consequences, both internal and external). And attitudes and ethics can and do evolve over time. Einstein may not have fully appreciated that his theory of Relativity applies to more than physics, but to ethics as well (ie. so-called moral relativism vs moral absolutism vs moral consequentialism, etc).

Flying grenade SG

"What is protonated alcohol?"

-_-" If you don't even know this, how are you gonna sit for your A level exams in 2 months' time? -_-"

If you don't understand his mechanism. then you need your school teacher or private tutor to explain the mechanism to you in-person. Move on.

*exclamation* yes , i figured out this mechanism alr, for pg 196.

the one missing curved arrow is at the first step. arrow from C-O bond to the O+ atom. (:

Flying grenade SG

no problem. thanks ultima for your replies, in and out of chemistry. i appreciate every single letter and word of it

definitely agree with Consequentialism and relativism.

yes i think its good to just put out the correct corrections online. i think and hope can benefit many.

also since i put in effort to proofread, which help my learning and setting my book right by doing necessary corrections, just put online for all to refer

i think it's a very good book. I've learn alot from it.

Flying grenade SG

[Fact]

Illustrated Glossary of Organic Chemistry - Term. Periplanar: Lying in the same plane, i.e., coplanar.

harvard : The term "periplanar" was coined by Klyne and Prelog in 1960 to define a flexible torsional angle of 0 ± 30° (syn) or 180 ± 30° (anti). The prefix peri, derived from the Greek for "near", was chosen to make the meaning"approximately planar".

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