Chemistry: Post your doubts here!

[abcde]

buuuh ! -.- funny -_-
meant jan !

There are no GCE O/AS/A-Level exams held in January. Are you talking about January exams of the Edexcel board?

 

[smzimran]

there ARE papers in two sessions: June or november not january

 

[DANGERBP]

There are no GCE O/AS/A-Level exams held in January. Are you talking about January exams of the Edexcel board?

ya !!

 

[DANGERBP]

there ARE papers in two sessions: June or november not january

MAN ! there is !!!

 

[DANGERBP]

MAN ! there is !!!

nd no november wat r u talkin about ?

 

[DANGERBP]

 

[smzimran]

nd no november wat r u talkin about ?

Are u asking abt Edexcel board?

 

[DANGERBP]

Are u asking abt Edexcel board?

haha man im screwed ! look all i know is am applyin for edexcel
nd some of my frndz did it in jan so thts what i was askin for !

 

[smzimran]

Well, i do not have much info abt the edexcel board

 

[DANGERBP]

Well, i do not have much info abt the edexcel board

oh ! nd where can i find some info about tht ?

thx anyways ! sorry for botherin ! =/

 

[smzimran]

oh ! nd where can i find some info about tht ?

thx anyways ! sorry for botherin ! =/

Use google

 

[abcde]

haha man im screwed ! look all i know is am applyin for edexcel
nd some of my frndz did it in jan so thts what i was askin for !

I understand. The correct sub-forum for you is this, which deals with discussion of Edexcel papers, etc: http://www.xtremepapers.com/community/forums/edexcel.17/
You can get advanced level chemistry papers from here: http://www.xtremepapers.com/Edexcel/index.php?dir=Advanced Level/Chemistry/
But the Jan 2012 is not available yet. :/

 

[DANGERBP]

I understand. The correct sub-forum for you is this, which deals with discussion of Edexcel papers, etc: http://www.xtremepapers.com/community/forums/edexcel.17/
You can get advanced level chemistry papers from here: http://www.xtremepapers.com/Edexcel/index.php?dir=Advanced Level/Chemistry/
But the Jan 2012 is not available yet. :/

thank you dude !!!!
apreciate tht !
ur a LIFE SAVER ! =p

 

[smzimran]

Plz solve this mcq:
A sample of chlorine containing isotopes of mass numbers 35 and 37 was analysed in a
mass-spectrometer.
How many peaks corresponding to
Cl2(charge on CL +1) were recorded?
A 2 B 3 C 4 D 5

C is the answer
The possible peaks are:
Cl-35 Cl-35
Cl-35 Cl-37
Cl-37 Cl-35
Cl-37 Cl-37

 

[DANGERBP]

Use google

heh thx !

 

[smzimran]

Use of the Data Booklet is relevant to this question.
What mass of solid residue can be obtained from the thermal decomposition of 4.10 g of
anhydrous calcium nitrate?
A 0.70g B 1.00g C 1.40g D 2.25g

C is the answer
Construct the equation:
Ca(NO3)2 -----> CaO + 2NO2 + (1/2)O2
solid residue is CaO
Mr is 164 and 56 respectively
So
Ca(NO3)2 : CaO
164 : 56
4.10 : x
By calculation,
x = (56*4.10)/164
x = 1.40

 

[DragonCub]

C is the answer
The possible peaks are:
Cl-35 Cl-35
Cl-35 Cl-37
Cl-37 Cl-35
Cl-37 Cl-37

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.

 

[abcde]

Plz solve this mcq:
A sample of chlorine containing isotopes of mass numbers 35 and 37 was analysed in a
mass-spectrometer.
How many peaks corresponding to
Cl2(charge on CL +1) were recorded?
A 2 B 3 C 4 D 5

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

 

[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........