Chemistry: Post your doubts here!

[funky brat]

Cis, Trans, and other will be shifiting of that R-O-CH2-O-R. Not sure. :3

They are actually drawn in the ms so I know this. In this sort of structures how do we come up with the number of isomers by just looking at it :/

 

[waqas123]

Guys, can somebody help me find the person who made these notes? I found them last year on xtremepapers and these have been immensely beneficial but these are for AS Level. I am looking for the A2 notes in this format. Maybe the author had created the A2 notes also.

For every chapter, there are syllabus points and then concise notes afterwards; very useful.

 

[My Name]

Guys, can somebody help me find the person who made these notes? I found them last year on xtremepapers and these have been immensely beneficial but these are for AS Level. I am looking for the A2 notes in this format. Maybe the author had created the A2 notes also.

For every chapter, there are syllabus points and then concise notes afterwards; very useful.
View attachment 60198 View attachment 60199

Guys, can somebody help me find the person who made these notes? I found them last year on xtremepapers and these have been immensely beneficial but these are for AS Level. I am looking for the A2 notes in this format. Maybe the author had created the A2 notes also.

For every chapter, there are syllabus points and then concise notes afterwards; very useful.
View attachment 60198 View attachment 60199

You mean you got these from here right?
A2 chapters have been added but not all.I hope that helps.

 

[waqas123]

You mean you got these from here right?
A2 chapters have been added but not all.I hope that helps.

Thanks a lot

 

[My Name]

Thanks a lot

Welcome

 

[Eugene99]

It's B, why?

 

[The Sarcastic Retard]

View attachment 60206
It's B, why?

Are u sure?

 

[Eugene99]

Are u sure?

oh sorry, C

 

[The Sarcastic Retard]

oh sorry, C

Its cos C-Cl bond is weaker than C-F bond.
So C-Cl bond breaks.

 

[Saad the Paki]

I'm confused on how to draw the structural formula for B. I know what it will be.

This is the mark scheme

This is my attempt is it correct?

 

[Rizwan Javed]

I think it should be something like this:
HO2CCH2CH(OCOCH3)CO2H

 

[Saad the Paki]

I think it should be something like this:
HO2CCH2CH(OCOCH3)CO2H

Is it important to be in the order of ' OCO ' ?

 

[Rizwan Javed]

Is it important to be in the order of ' OCO ' ?

Yes, otherwise it will fell like C of the OH group is attached to C if we're writing it like this COO instead of OCO.

 

[ahmedish]

I have never seen such eqaution in As level group I.
Come on tell me, Li + H2O will give you Li2O or Li(OH) ??

I mean group 1 + H2O give hydroxides so thats why

 

[cashew]

http://studyguide.pk/Past Papers/CI... AS Level/9701 - Chemistry/9701_s10_qp_42.pdf
PLEASE, help with Q3 di)

 

[Eugene99]

how is the ester propyl methanoate?

 

[The Sarcastic Retard]

View attachment 60228
how is the ester propyl methanoate?

Methanoic acid + propanol = Propyl methanoate

 

[qwertypoiu]

http://studyguide.pk/Past Papers/CIE/International A And AS Level/9701 - Chemistry/9701_s10_qp_42.pdf
PLEASE, help with Q3 di)

You have to play with the numbers to try to deduce the species responsible for each mass peak. Start with the smallest one and build on from there:

133 - SiCl3

I got this by subtracting various mass numbers from 133 on my calculator and this worked.

Next step is 149, which is 16 away, so just add O:

149 - SiCl3O

Next is 247... That's 98 we have to add. Cl2 gives 70, and Si another 28! So:

247 - Si2Cl5O

Then 263.... That's again a leap of 16:

263 - Si2Cl5O2

Next we have 396... 133 to jump! Get rid of 70 again with Cl2. 63 left. The last digit of 63 is 3, and that could be made by numbers ending with 8 and 5. Basically, 28 + 35 = 63. So we add SiCl3 more:

396 - Si3Cl8O2.

 

[areeba240]

how will we know which compound is oxidised

 

[areeba240]

why cant the anwser be B