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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...

UltimaOnline SG

what about this?

One way to create a pseudo-1st-order reaction is to manipulate the physical amounts of the reactants. For example, if one were to dump a liter of 5 M HCl into a 55 M ocean, the concentration of the mixture would be closer or equal to that of the ocean because there is so much water physically compared to the HCl and also because 55 M is relatively larger compared to 5 M.

this is for http://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Kinetics/Reaction_Rates/Second-Order_Reactions/Pseudo-1st-order_reactions

So what don't u understand?

Flying grenade SG

So what don't u understand?

it's like making H2O pseudo first order

UltimaOnline SG

it's like making H2O pseudo first order

Go ask your school teacher or private tutor, u coconaden.

Buay tahan. Tak boleh tahan. Going out for makan now, be back after midnight. Move on, don't make me vomit blood with this qn liao.

Flying grenade SG

i think its make HCl pseudo first order from second order

yeah ok moved on

Flying grenade SG

Go ask your school teacher or private tutor, u coconaden.

Buay tahan. Tak boleh tahan. Going out for makan now, be back after midnight. Move on, don't make me vomit blood with this qn liao.

i stopped asking my school chemistry teachers qns long long time ago

Flying grenade SG

what about this?

this is for http://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Kinetics/Reaction_Rates/Second-Order_Reactions/Pseudo-1st-order_reactions

so pseudo first order not very useful/relevant to H2 chem?

UltimaOnline SG

so pseudo first order not very useful/relavant to H2 chem?

See my BedokFunland JC qns on my website, then you'll see if it's relevant to H2 Chem or not (but DON'T ask about those qns here on the forum). Go ask ur school teacher or private tutor instead.

Flying grenade SG

the oxdn number of carbonyl C atom in benzaldehyde is between 0 and +1 ?

how to determine the exact value for these type of cases? also the N atom in nitrobenzene is between +3 and +5?

Flying grenade SG

for other normal aliphatic aldehyde, O.N. of C atom is +1 right

Flying grenade SG

https://www.dropbox.com/s/9coywg6c8q0nzl4/20161005_214555.jpg?dl=0

https://www.dropbox.com/s/j9bagm5kenl8m3s/20161005_214614.jpg?dl=0

how is it that Uand V yield the same products on ozonolysis

W and X also

U,V and W,X all have diff structural formula

http://chem.libretexts.org/Core/Organic_Chemistry/Hydrocarbons/Alkenes/Reactivity_of_Alkenes/Ozonolysis

only ketone CH3CH2COCH3 generated from oxidation of X via ozonolysis can be distinguished only

UltimaOnline SG

the oxdn number of carbonyl C atom in benzaldehyde is between 0 and +1 ?

how to determine the exact value for these type of cases? also the N atom in nitrobenzene is between +3 and +5?

If resonance is involved, the actual value will be a *weighted* average of the values in the resonance contributors.

You need to correctly deduce the OS value in the individual resonance contributors, before you can correctly elucidate the actual OS value in the resonance hybrid.

You go draw out the resonance contributors of nitrobenzene, then see if you get " between +3 and +5" or not, you coconaden.

UltimaOnline SG

for other normal aliphatic aldehyde, O.N. of C atom is +1 right

Obviously. The carbonyl C atom has the same OS in both resonance contributors.

UltimaOnline SG

https://www.dropbox.com/s/9coywg6c8q0nzl4/20161005_214555.jpg?dl=0

https://www.dropbox.com/s/j9bagm5kenl8m3s/20161005_214614.jpg?dl=0

how is it that Uand V yield the same products on ozonolysis

W and X also

U,V and W,X all have diff structural formula

http://chem.libretexts.org/Core/Organic_Chemistry/Hydrocarbons/Alkenes/Reactivity_of_Alkenes/Ozonolysis

only ketone CH3CH2COCH3 generated from oxidation of X via ozonolysis can be distinguished only

First of all, if you use ozonolysis, you *must* specify "oxidative workup" or "reductive workup" or Cambridge will penalize you.

Second (once you've chosen oxidative or reductive), then draw out all the products.

If they're not the same, then they're not the same lah! (in which case, authors also can make typos ok! you urself know can liao!)

If they're the same, then *that's why* they're the same lah! (in which case, who say different reactants cannot generate the same products after a reaction?)

Flying grenade SG

molecules with diff structural formula generate same product after a reaction, eg. oxidative cleavage? agree, its possible

I know CH3CHO can be produced by both U and V

i dont see how CH3CH2CH2CHO can be produced from V

how would X produce CH3CHO and CH3CH2COCH3?

from the qn : how to use ozonolysis to differentiate these structural isomers of C6H12

Flying grenade SG

ok moved on alr. thanks for your patience

no need reply these qns, can selective reply some and some not, i dun mind

this not impt, moved on alr

if serious or impt qn then i will implore/beg/pester u to reply

UltimaOnline SG

molecules with diff structural formula generate same product after a reaction, eg. oxidative cleavage? agree, its possible

I know CH3CHO can be produced by both U and V

i dont see how CH3CH2CH2CHO can be produced from V

how would X produce CH3CHO and CH3CH2COCH3?

from the qn : how to use ozonolysis to differentiate these structural isomers of C6H12

If they're not the same, then they're not the same lah! (in which case, authors also can make typos ok! you urself know can liao!)

Flying grenade SG

open ended qn : how to differentiate U,V , W, X

is it too complicated to systematically differentiate that 4 isomers of C6H12?

Flying grenade SG

fact :

ester group bonded to benzene ring is https://en.m.wikipedia.org/wiki/Ethyl_benzoate. methyl benzoate too. produced from benzoic acid as the carboxylic acid

https://en.m.wikipedia.org/wiki/Phenyl_acetate , produced from phenol and ethanoic acid

UltimaOnline SG

open ended qn : how to differentiate U,V , W, X

is it too complicated to systematically differentiate that 4 isomers of C6H12?

Flying grenade SG

https://www.dropbox.com/s/nbb33pfyobl68uj/20161005_233018.jpg?dl=0

1. LiAlH4 in dry ether

2. followed by H2O/ heat? no need heat right?

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