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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

I am so dead. This i also dk how do

Ultima help me please

https://www.dropbox.com/s/52xg56a9dwrn9zp/20160526_125914.jpg?dl=0

Why is left C oxidation state of -3?

Is it because from

https://en.m.wikipedia.org/wiki/Electronegativities_of_the_elements_(data_page), carbon more e-ve than hydrogen?

In between C-C bond no electron withdrawing or donating, cus e-ve same between 2 carbon atoms, assume both share e- equally, hence C connected to C do not affect oxidation state right?

For ethanoate ion, i can't find my mistake! ! Help me please T-T. The O with mononegative charge has oxidation state of -1 right?

Flying grenade SG

For acidification, is it right to write proton transfer acidification reaction?

I'm asking this because, for example, there's no meaning in stating 'esterification' when forming ester, we write condensation+NU Sub , etc

So just wondering if there's a more precise way to describe acidification

UltimaOnline SG

I am so dead. This i also dk how do

Ultima help me please

https://www.dropbox.com/s/52xg56a9dwrn9zp/20160526_125914.jpg?dl=0

Why is left C oxidation state of -3?

Is it because from

https://en.m.wikipedia.org/wiki/Electronegativities_of_the_elements_(data_page), carbon more e-ve than hydrogen?

In between C-C bond no electron withdrawing or donating, cus e-ve same between 2 carbon atoms, assume both share e- equally, hence C connected to C do not affect oxidation state right?

For ethanoate ion, i can't find my mistake! ! Help me please T-T. The O with mononegative charge has oxidation state of -1 right?

Obviously. OS = -1 + -1 = -2

UltimaOnline SG

For acidification, is it right to write proton transfer acidification reaction?

I'm asking this because, for example, there's no meaning in stating 'esterification' when forming ester, we write condensation+NU Sub , etc

So just wondering if there's a more precise way to describe acidification

Bronsted-Lowry acidification or protonation.

Flying grenade SG

Obviously. OS = -1 + -1 = -2

I found my mistake le. Lmao!!! O.s. of O is -2.

Thanks ultima !!!

Flying grenade SG

Bronsted-Lowry acidification or protonation.

Thanks !!!

Flying grenade SG

What does proticity mean? Can't find the meaning online

Is it mean how many H it can donate?

U.O. told me that formula of salt formed is based on proticity, based on the discussion of george chong's inorganic book having a error at page 40

Flying grenade SG

[IGNORE this epic fail post. Found my mistake, written below]

Omg wtf, ultima hope u can help on this

Page 40 george chong's inorganic book

Oxides of phosphorus with alkalis :

(After making corrections) product when p4o6 react with NaOH is Na2HPO3 . I calculated o.s. of P is +3 (can help check?)

Product when p4o10 react with NaOH is Na3PO4. I calculated o.s. of P is +5 (can help check? )

!? Wait. Update : for george chong's inorganic book, i have serious anomalous results compared to his writing

On both pages 40 and 41, specifically Oxides of P and oxides of S parts , he wrote Four times, that when oxides dissolve in water/neutralised by alkalis , oxidn number/state do not change ! Neutralisation, dissociation are not redox reactions

But I've calculated o.s. if all the P and S compounds in page 40 and 41, the o.s. aren't the same(e.g. the top portion of this post) !!!

Please please help !!

Flying grenade SG

Shit la. Actually i think i made a serious blunder

He meant o.s. of p in p4o10 and os in na3po4 is the same, +5. SOOORRRRYRYYY !!

UltimaOnline SG

What does proticity mean? Can't find the meaning online

Is it mean how many H it can donate?

U.O. told me that formula of salt formed is based on proticity, based on the discussion of george chong's inorganic book having a error at page 40

Proticity refers to how many protons a Bronsted-Lowry acid can donate, or how many protons a Bronsted-Lowry base can accept. Eg. H3PO4 is a triprotic acid, hence PO4 3- is a triprotic base.

Since H3PO3 (Latin name phosphorous acid, Stock name phosphoric(III) acid, IUPAC name phosphonic acid) is a diprotic acid, hence upon complete deprotonation using excess NaOH(aq) in a Bronsted-Lowry acid-base reaction, the salt generated is Na2HPO3 (Latin name disodium phosphite, Stock name disodium phosphate(III), IUPAC name disodium phosphonate).

Flying grenade SG

Thanks alot !!

Flying grenade SG

Is it possible to synthesise methanal ? As it will further oxidise to co2 and h2o

Use methanol, k2cr2o7, heat with immediate distillation, can get methanal?

Flying grenade SG

Hi Ultima, hope you can help me, please !

https://www.dropbox.com/s/5kz1e3dc81gswep/20160527_125045-1.jpg?dl=0

UltimaOnline SG

Is it possible to synthesise methanal ? As it will further oxidise to co2 and h2o

Use methanol, k2cr2o7, heat with immediate distillation, can get methanal?

Obviously methanal can be synthesized.

https://en.wikipedia.org/wiki/Formaldehyde#Industry

Using methods within H2 syllabus will have very low yield. Cambridge will understand this and either not ask, or will accept the within-syllabus method, etc.

UltimaOnline SG

Hi Ultima, hope you can help me, please !

https://www.dropbox.com/s/5kz1e3dc81gswep/20160527_125045-1.jpg?dl=0

This problem you need to ask your school teacher or private tutor face-to-face, because it's not a simple balancing of equation using molecular formulae, as it involves molecular structures and mechanisms, cannot efficiently settle on forum.

Flying grenade SG

Ultima, can help me check my answers and teacher's answer at the left column? For the 2nd product, i thought its methanoic acid, but my cher say it's co2, idk why

UltimaOnline SG

Ultima, can help me check my answers and teacher's answer at the left column? For the 2nd product, i thought its methanoic acid, but my cher say it's co2, idk why

Because methanoic acid is further oxidized to carbonic acid, which decomposes into carbon dioxide and water.

Flying grenade SG

THANKSSSSSSS ULTIMAA!!!

Flying grenade SG

Hi ultima, can help page 10 chan kim seng planning book?

Don't understand double titration method to find the actual amount of diprotic K2CO3

UltimaOnline SG

Hi ultima, can help page 10 chan kim seng planning book?

Don't understand double titration method to find the actual amount of diprotic K2CO3

This one you need actually to *DO* (not just read or type out notes for) this type of double-titration calculation question, preferably with the face-to-face guidance of your school teacher or private tutor. Cannot settle on forum.

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