Chemistry: Post your doubts here!

[tom ed]

Is it C? I think Cl-35 Cl-37 and Cl-37 Cl-35 shall show as the same peak. The mass spectrometre measures the mass-to-charge ratio of Cl2 molecules, not Cl atoms.

i agree....the answer shud b "B".......

 

[tom ed]

AoA!
B. 3 peaks will be recorded corresponding to Cl2 (1+). Chlorine atoms can exist in the form of Cl-35 and Cl-37. So the three peaks will correspond to the following three possibilities of Cl2 (1+):
-> Cl-35 and Cl-37
-> Cl-35 and Cl-35
-> Cl 37 and Cl-37

exactly........

 

[sweetiepie]

For Notes Check here

http://www.xtremepapers.com/community/threads/some-different-notes-website-are-available.10423/

 

[smzimran]

Is it C? I think Cl-35 Cl-37 and Cl-37 Cl-35 shall show as the same peak. The mass spectrometre measures the mass-to-charge ratio of Cl2 molecules, not Cl atoms.

Hmm, u r right...

I admit my mistake there

 

[TheDealer]

Guys n girls i need some help here in Q27 from this paper:
http://www.xtremepapers.com/CIE/International A And AS Level/9701 - Chemistry/9701_s03_qp_1.pdf
How do we know which atom is removed to form the radical? :S

 

[MEGUSTA_xD]

http://www.xtremepapers.com/CIE/International A And AS Level/9701 - Chemistry/9701_s08_qp_1.pdf
Question number 5 6 7. Help

 

[smzimran]

Guys n girls i need some help here in Q27 from this paper:
http://www.xtremepapers.com/CIE/International A And AS Level/9701 - Chemistry/9701_s03_qp_1.pdf
How do we know which atom is removed to form the radical? :S

C
Only C-Cl bond is broken by uv light

 

[smzimran]

http://www.xtremepapers.com/CIE/International A And AS Level/9701 - Chemistry/9701_s08_qp_1.pdf
Question number 5 6 7. Help

5 is simple Me3N is tetrahedral due to 3 bonds and lone pair
BF3 is planar 'In final compound both must be tetrahedral
C is correct

 

[TheDealer]

alright thanks man...n btw...the only other kinds of bonds broken by UV light are between halogens rite?

 

[smzimran]

http://www.xtremepapers.com/CIE/International A And AS Level/9701 - Chemistry/9701_s08_qp_1.pdf
Question number 5 6 7. Help

6.
First find the mass of ice by using formula:
mass = density * volume
m = 1 * 1 = 1 g
We know that Mr(H2O) = 18
So, number of moles = m/Mr
n = 1/18 = 0.055
The ideal gas equation is:
pV = nRT
V = nRT/p
V = 0.05 * 8.31 * 596 / 101
V = 2.67
So, C is the answer...

 

[smzimran]

http://www.xtremepapers.com/CIE/International A And AS Level/9701 - Chemistry/9701_s08_qp_1.pdf
Question number 5 6 7. Help

7.
It cannot be A because one is metal other is non metal;
not B because one is non metal and other is noble gas
not C because one is metal and other is giant moleculer
So, it is D, because both are non metals having simple molecular structures...

 

[sahania]

please help me with chemistry paper 3 . i'm having problems in moles calculations and over all paper 3 ... please help

 

[smzimran]

please help me with chemistry paper 3 . i'm having problems in moles calculations and over all paper 3 ... please help

http://www.xtremepapers.com/community/threads/tips-for-chemistry-practicals-p3.11810/
Here

 

[TheDealer]

the only other kinds of bonds broken by UV light are between halogens rite?

 

[tom ed]

http://www.xtremepapers.com/community/threads/tips-for-chemistry-practicals-p3.11810/
Here

may i ask ....hw did u prepare for ur chem paper....i mean any good book u'd like to suggest...or were u simply dependent upon past paper practice and ur teacher's notes......wats the best way....??

 

[smzimran]

may i ask ....hw did u prepare for ur chem paper....i mean any good book u'd like to suggest...or were u simply dependent upon past paper practice and ur teacher's notes......wats the best way....??

Just practise and one important thing i will tell you p.m me

 

[TheDealer]

dude answer my question -_-

 

[smzimran]

the only other kinds of bonds broken by UV light are between halogens rite?

The only thing u need to know in AS is that uv light breaks C-halogen bond, no detail needed about halogen-halogen bonds

 

[TheDealer]

alrite...oh n Q20 of O/N 2005 confused me too.
http://www.xtremepapers.com/CIE/International A And AS Level/9701 - Chemistry/9701_w05_qp_1.pdf

 

[smzimran]

alrite...oh n Q20 of O/N 2005 confused me too.
http://www.xtremepapers.com/CIE/International A And AS Level/9701 - Chemistry/9701_w05_qp_1.pdf

B is the answer....