Chemistry: Post your doubts here!

[Rohaan Nadeem]

It

here i know my writing is a bit too small

It's actually very small but thanks,I was in a desperate need.

 

[insomniac]

Haha sorry

i think u didnt check the question properly... the question is from ionic equilibria
anyways thanks

ur ppr mixed up with a phy ppr in my docs n i answered it oops

 

[andrewcxw]

S11 QP22
Question 1 (c)(i)

Answer to (b)(iv) is 0.04, by the way.

Why are the reactants 0.04 and products 0.06?

 

[6Astarstudent]

S11 QP22
Question 1 (c)(i)

Answer to (b)(iv) is 0.04, by the way.

Why are the reactants 0.04 and products 0.06?

0.04 mol of NaOH reacted with ethanoic acid.
Since CH3COOH reacts with NaOH in 1 to 1 ratio so there was 0.04 mol of CH3COOH left in the equilibrium.
and we know reaction CH3CO2H + ROH -> CH2CO2R + H2O happens in 1:1:1:1 ratio
and CH3CO2H same initial amount as ROH so ROH must be 0.o4mol as well
and CH3CO2R = 0.1-0.04 = 0.06 = H2O

 

[PrincessLuna]

For chemistry P3, any tips regarding errors and source of limitation questions of each type? thanks.

 

[Afza Munir]

NEED HELP!!!!!
when a propanone dissolves in water , it forms a hydrogen bond with water?
a: what features must water and propanone molecules posses in order to form a hydrogen bond?
b: draw a diagram to show a propanone moleculeand a water molecule forming a hydrogen bond

 

[danyaljamil]

NEED HELP!!!!!
when a propanone dissolves in water , it forms a hydrogen bond with water?
a: what features must water and propanone molecules posses in order to form a hydrogen bond?
b: draw a diagram to show a propanone moleculeand a water molecule forming a hydrogen bond

1)both propane and water must possess highly electronegative atom with atleast one lone pair of electron and atleast one of the molecule must have a hydrogen atom attached to such a electronegative atom
2)show atleast 2 h-bonds with partial positive and negative shown on the right atoms along with the lone pairs

 

[danyaljamil]

For chemistry P3, any tips regarding errors and source of limitation questions of each type? thanks.

generally for heating experiments loss of heat from the container due to convection if the container is uncovered and by conduction if wool or any other material is not used for lagging also if some solid is tipped into a liquid for a reaction then you can mention that some of the solid is lost and does not react when the mixture foams as far i remember limitations are only asked for enthalphy change reactions but correct me if otherwise

 

[Afza Munir]

1)both propane and water must possess highly electronegative atom with atleast one lone pair of electron and atleast one of the molecule must have a hydrogen atom attached to such a electronegative atom
2)show atleast 2 h-bonds with partial positive and negative shown on the right atoms along with the lone pairs

thnks alot dude...

 

[Musab100]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_22.pdf

can anyone explain me some questions:
Q1 part(a) why we cant use ZnNO3 ???
Q2 a(ii) ???
Q4 (a) product C how it is formed ??
Q 5 b(i) ??

 

[Musab100]

isomers

 

[danyaljamil]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_22.pdf

can anyone explain me some questions:
Q1 part(a) why we cant use ZnNO3 ???
Q2 a(ii) ???
Q4 (a) product C how it is formed ??
Q 5 b(i) ??

Q1 part(a )znN03 is neutral or weakly basic? im not sure myself so a better answer would be to use carbonate and hydroxides or znO which we know react with acids
Q2 the atomic radius increases down the group of halogens so the force of attraction on the shared pair of e- from the nucleus decreases so the bond becomes weaker down the group and is much easier to overcome
Q4 (a) C is a carboxlyic acid that reacts with the naoh that is basic in nature forming a salt with OH group in COOH replaced by sodium
Q 5 b(i) the two should show be optical isomers of each other just attach 4 different molecules or atoms to one of the carbon and shows both the isomers! and the other two should be cis-trans isomers

 

[Musab100]

Q1 part(a )znN03 is neutral or weakly basic? im not sure myself so a better answer would be to use carbonate and hydroxides or znO which we know react with acids
Q2 the atomic radius increases down the group of halogens so the force of attraction on the shared pair of e- from the nucleus decreases so the bond becomes weaker down the group and is much easier to overcome
Q4 (a) C is a carboxlyic acid that reacts with the naoh that is basic in nature forming a salt with OH group in COOH replaced by sodium
Q 5 b(i) the two should show be optical isomers of each other just attach 4 different molecules or atoms to one of the carbon and shows both the isomers! and the other two should be cis-trans isomers

thanks buddy

 

[goodluckayesha]

Can anyone post topical past papers (paper 4) for lattice energy and electrode potential ASAP? Plz?
Thanks in advance!

 

[1357911]

Can anyone post topical past papers (paper 4) for lattice energy and electrode potential ASAP? Plz?
Thanks in advance!

Lazy! Dhoond kr karo khud..
U r welcome in advance.

 

[goodluckayesha]

Lazy! Dhoond kr karo khud..
U r welcome in advance.

Plz yaar tell me or else link do

 

[1357911]

Plz yaar tell me or else link do

I have to start today janab jee. jab kr loon gi ill tell u... Btw chemistry ke jahan tak mein nei questions kiye hain topical nahi hain. They are all mixed up. Jumbled up. Aik Aik question men do do teen chapters ke questions hain. So be careful when solving.

 

[goodluckayesha]

I have to start today janab jee. jab kr loon gi ill tell u... Btw chemistry ke jahan tak mein nei questions kiye hain topical nahi hain. They are all mixed up. Jumbled up. Aik Aik question men do do teen chapters ke questions hain. So be careful when solving.

Oh god!

 

[salvatore]

Could someone please help me with the following question?
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_42.pdf
qn no. 1 (iv)

I do not understand how the mechanism is drawn in the marking scheme. In addition, I also don't get why the examiners report has stated that this is an SN2 mechanism. I'll appreciate if someone could help me solve this.

Thanks

 

[Musab100]

product b and e