AS Chemistry P2 Prep.

[mujtabashahnawaz]

are you sure? isnt elimination the removal of water? :O

Yes i am sure, elimination is not used for water

 

[smartangel]

http://www.xtremepapers.com/papers/... AS Level/Chemistry (9701)/9701_w11_qp_21.pdf
Q3d...isnt the formula of calculating enthalpy change..Enthalpy change of products - enthalpy change of reactants...?? ms is doing the opposite..

 

[angelgirl:)]

No, the term elimination is only used for alkyl halides, not for H2O removal.

yes it does....check the ms

 

[angelgirl:)]

Yes i am sure, elimination is not used for water

ok post me the ms which they they reject elimination word for water removal...

 

[mujtabashahnawaz]

yes it does....chect the ms

Can u post the link of ms please?

 

[Jaf]

Is P4O6 in our syllabus or P4O10? If we are asked for an oxide of Phosphorus, which one will we quote?

The latter.

 

[mujtabashahnawaz]

ok post me the ms which they they reject elimination word for water removal...

I haven't seen the ms, but my teachers have told me that we have only one elimination reaction in syllabus and that is for alkyl halides.

 

[mujtabashahnawaz]

The latter.

thanks

 

[saudha]

mass spectroscopy-mass of each isotope of an element in it....
1 vaporisation
2 ionisation
3 deflection
4 detection
the mass spectrum shows relative abundance against ion charge
Determination of Ar from mass spectra
multiply each isotopic mass by its % abundance
add the figures
divide by 100

 

[Saad (سعد)]

I haven't seen the ms, but my teachers have told me that we have only one elimination reaction in syllabus and that is for alkyl halides.

As-Salaamu 'Alaykum;

http://www.xtremepapers.com/papers/...and AS Level/Chemistry (9701)/9701_s04_ms.pdf

They accepted both dehydration and elimination in question 4 part (c) in that MS.

But never trust examiners. >.> Just write both.

 

[angelgirl:)]

Can u post the link of ms please?

m/j 2009p22
Q5c

 

[saudha]

avogadro constant-6.02x1o^23
moles=mass/RMM
to find mass of products in a chemical reaction:
1-mass of the reactants
2-molar mass of the reactants
3-balanced equation

 

[Jaf]

But never trust examiners. >.> Just write both.

Not a good idea. Writing both implies you're confused which one. Write any one (preferably dehydration).

 

[mujtabashahnawaz]

As-Salaamu 'Alaykum;

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s04_ms.pdf

They accepted both dehydration and elimination in question 4 part (c) in that MS.

But never trust examiners. >.> Just write both.

m/j 2009p22
Q5c

Thanks a lot both of you. but we can't write both so write dehydration for H2O and elimination for alkyl halides, as this can't be wrong in any case. Who knows the examiner!

 

[angelgirl:)]

Not a good idea. Writing both implies you're confused which one. Write any one (preferably dehydration).

of course ...u have to right 1...never right multi answer...

 

[saudha]

% by mass=atoms x no of moles of an element/molar mass of compound x100

 

[Saad (سعد)]

Not a good idea. Writing both implies you're confused which one. Write any one (preferably dehydration).

o.o;

Hmm... I guess.

Edit: Question; Summer/June 2004, question 3, part (d):

Paper: Click me!
Mark Scheme: No, click me!

Is it important to show the 'balloon'-shaped thing over ammonia for the lone pair that's drawn in the Mark Scheme? If so, why, because in the question they only asked for the shape and the bond angle...

Jazak Allah Khayr.

 

[angelgirl:)]

ok ppl a humble request to all the user of the threads...wen ever u r posting any information...be very carefulll and 100% sure ...coz the students from all over the world will be accessing to this thread...

 

[saudha]

ok anglegirl...... know abt spectator ions?

 

[angelgirl:)]

ok anglegirl...... know abt spectator ions?

yes ...it means the ions which dont take prt in the reaction...means remains in the solution same