Chemistry Paper 4-theory- doubts =D

[AlishaK]

WHAT??!!! I don't know anything like that?!!

OMG! it exists. According to google!

 

[AlishaK]

and..umm.. are we discussing math in here?

hahha...galti sai posted! :/

 

[knowitall10]

if not, i ain't wastin any tiny bit of energy i have saved 4 tmw

 

[knowitall10]

hahha...galti sai posted! :/

acha acha..koi gal nahi

 

[Ramsha007]

just memorize it i think it has a difficult way to find the ratio and we r not doing a math exam to be asked how to find their ratios..that would be a stupid question from the examiner

Well said!!! I will stick to memorizing!

 

[xhizors]

okay means koi logic nahi hai, just have to learn it Right

a key point for mass spectrometry
if M and M+2 peaks are in ratio of 3:1 means chlorine is present
if M and M+2 peaks heights are in ratio of 1:1 than Bromine is in mixture (only one bromine)

 

[PhyZac]

Can u like tell me the second step? as in when it says, sin45=real p/ 2(1+2^1/2)=1/2^1/2 ?? :S

See.
Sin 45 [since 45 is then angle]
sin = opp/hyp
opp is the real of P the x coordinate of P
hyp is OP

And what is written is

Sin 45 = real p/2(1+√2)
1/√2 = real p /2(1+√2)
real p = 2(1+√2) /1/√2

 

[AlishaK]

do we need to know it?

Are we Google?

 

[Ammar Naeem]

Chemistry P4+ Maths p3 tommorow! Allah bachaee

 

[xhizors]

WHAT??!!! I don't know anything like that?!!

so plz know it

 

[Ramsha007]

a key point for mass spectrometry
if M and M+2 peaks are in ratio of 3:1 means chlorine is present
if M and M+2 peaks heights are in ratio of 1:1 than Bromine is in mixture (only one bromine)

is it going to be written in q that the ratio is this?????

 

[xhizors]

Well said!!! I will stick to memorizing!

if 2 Cl are included in mixture say Ch2Cl2
u'll get peaks M (M+2)x2 and M+4
heights ratio 9:6:1
for br2 included u get 1:2:1 ratio
stay tune for y part

 

[xhizors]

ac

is it going to be written in q that the ratio is this?????

actually 35Cl is in 75% occuring in nature and 37Cl is 25% thats y ratio is 3:1

 

[xhizors]

ok so whoz up whoz up?? for organic?

 

[kiara15]

http://www.chemguide.co.uk/CIE/sect113menu.html#top

hey thanks genious and good luck for papers

 

[AlishaK]

if 2 Cl are included in mixture say Ch2Cl2
u'll get peaks M (M+2)x2 and M+4
heights ratio 9:6:1
for br2 included u get 1:2:1 ratio
stay tune for y part

M will hav the highest ratio?!

 

[Oliveme]

[Fe(H2O)6-n(NO2)n]^2+ (n=1 to 6) how do we get this?

Q3 (D) why is that ketone getting reduced to -OH using Ni? ! M/J 2012 p41

For the first question,
[Fe(H2O)6-n(NO2)n]^2+ (n=1 to 6) -----> simply means that if you have 2 NO2 ligands with Fe, then the H2O ligands will be 6-n = 6-2 = 4 H2O ligands. and the formula becomes ----> [Fe(H2O)4(NO2)2]^2+
n can be any number from 1 to 6, because Fe can only have a maximum of 6 ligands attached. There is a +2 charge on the entire complex because of the +2 charge on Fe - they don't exactly form a compound, it's a complex with dative bonds and the ligands donating a pair of electrons. Hope it's clear.

 

[AlishaK]

For the first question,
[Fe(H2O)6-n(NO2)n]^2+ (n=1 to 6) -----> simply means that if you have 2 NO2 ligands with Fe, then the H2O ligands will be 6-n = 6-2 = 4 H2O ligands. and the formula becomes ----> [Fe(H2O)4(NO2)2]^2+
n can be any number from 1 to 6, because Fe can only have a maximum of 6 ligands attached. There is a +2 charge on the entire complex because of the +2 charge on Fe - they don't exactly form a compound, it's a complex with dative bonds and the ligands donating a pair of electrons. Hope it's clear.

ohhh...thanks i just realised my mistake...i was taking 'Fe' atom instead of ion so it cd only accommodate 4 ligands. Okay so is it necessary to include H2O whn such ques r asked or depends on....?!
Thanks a ton! Stay blessed!

 

[Oliveme]

ohhh...thanks i just realised my mistake...i was taking 'Fe' atom instead of ion so it cd only accommodate 4 ligands. Okay so is it necessary to include H2O whn such ques r asked or depends on....?!
Thanks a ton! Stay blessed!

Yes, with Fe, H2O ligands are important to include.

 

[AlishaK]

Yes, with Fe, H2O ligands are important to include.

Can u gimme a few more examples for a) metal ions in which H2O is imp b) for which it aint imp.

Jazak Allah Khair!