AS Chemistry Doubts

[robotic94]

the CH mole ratio of esters and carboxylic acid is same! :O HOWWW?

 

[Student12]

the CH mole ratio of esters and carboxylic acid is same! :O HOWWW?

Carboxylic acid general formula is CnH2n +1 COOH - Hydrogen to Carbon ratio
There are total 2 carboon and 4 hydrogen , 2 cancel out you get 1 carbon and cancel 4 you get 2 so its 1:2

Ester the general formula is- CnH2n +1 COO CmH2m+1 The Hydrogen are 6 : and carbon are 3.. After cancelling there will be 2 hydrogen and 1 carbon which is again 2:1

 

[sidbloom]

can any one tell me how to find mole ratio in a give ionic equation and how to find moles through that
please help me fast

 

[iFuz]

ClO2
Cl2O7

Reaction of these oxides with water?

 

[sidbloom]

i have a question reguarding paper of 2003 may june Q.5 part c (i)
the answer is quite simple i know but what i want to ask is what is the difference between not biodegradable and not effected by enzyme.....
i mean it will be not biodegradable it enzyme cannot act on them right......

 

[USMAN Sheikh]

need help q1 part c ?? is ms wrong ?? pls

 

[sonaly]

40 A monomer undergoes addition polymerisation. A 1 mol sample of the monomer is completely
polymerised.
How many moles of polymer might, theoretically, be formed?
1. 1
2 10^–6
3 1/ 6.02 10^23..
this is Q40 0f http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w09_ms_12.pdf..statemnts 2 adn 3 are correct. HOW??PLZ EXPLAIN!

if u got the ans plz explain.
thanks!!

 

[TCHS]

http://www.xtremepapers.com/papers/... AS Level/Chemistry (9701)/9701_s12_qp_12.pdf

Question 16 please?!

 

[TCHS]

http://www.xtremepapers.com/papers/... AS Level/Chemistry (9701)/9701_s12_qp_12.pdf

Question 23??

 

[rawaaaan]

Hi , please i need answer for question 19 May June 2009 paper 1 ( about chiral centre )

the first one is near the carbon which have 0h bonded to it cuz this C atom have 4 different groups oh,h and the other 2 from the sides
the second one is the C atom bonded to ch3 as u can see it have 3 lines and they r different and the fourth one i ch3
the third one is again the other one bonded to the other C atom
the fourth one in in the upper rings the second one n the right side ,it have 3 lines and the fourth one is H AND JUST BESIDE IT IS ANOTHER ONE AND AGAIN THE ONE BESDE IT IS ANOTHER CHIRAL CARBON ,so as u can notice there are 2 chiral centres on one ring ,this rinf is the upper one the second on the right,hope u understood cuz its hard to explain ,if u want i'll try to send a pic marking them

 

[rawaaaan]

question 9 plz june 11 paper 1 variant 1 (11) for molar enthalapy

 

[SomeStudent]

 

[SomeStudent]

please explain the reasons for all the options given.

 

[Hassan Ali Abid]

View attachment 36643

Ans is B . hydrolysis ..

 

[SomeStudent]

Ans is B . hydrolysis ..

I know that. I am asking how so.

 

[Hassan Ali Abid]

I know that. I am asking how so.

That compound is having an ester linkage...and its acid or base hydrolysis is possible thats why the ans is B.
This compound is not having any C=C so addition is not possible,similarly reduction is not possible ,free radical substitution is possible but the conditions etc are not stated in the question so this option is also eliminated and the remaining option is B.

 

[Hassan Ali Abid]

please explain the reasons for all the options given.View attachment 36644

No C=C are available so addition if bromine is not possible hence bromine will not be decolourised.
Option B is incorrect as this compound is soluble in water as OH is present which means it can easily form Hydrogen bonding with water so its soluble,
It cant reduce fehling's solution as no aldehyde group is available hence this reaction will not occur.
This reaction will occur.The compound contains both the acid and the alcohol groups so when strong acid such as H2SO4 will be acting as catalyst the two molecules of Lactic acid will react and esterification will occur so the ans is D.

 

[SomeStudent]

No C=C are available so addition if bromine is not possible hence bromine will not be decolourised.
Option B is incorrect as this compound is soluble in water as OH is present which means it can easily form Hydrogen bonding with water so its soluble,
It cant reduce fehling's solution as no aldehyde group is available hence this reaction will not occur.
This reaction will occur.The compound contains both the acid and the alcohol groups so when strong acid such as H2SO4 will be acting as catalyst the two molecules of Lactic acid will react and esterification will occur so the ans is D.

Thanks! I got

 

[omaaaar]

Could anyone tell me on how to prepare to solve the organic chemistry Mcqs question they are way too difficult.

 

[Hassan Ali Abid]

Could anyone tell me on how to prepare to solve the organic chemistry Mcqs question they are way too difficult.

First prepare the Organic equations and once you get hold of it and as soon as they are fingre tips the mcqs will become easy for you....P.s your recalling power must be strong as you have to solve the paper in one hr.