ANY DOUBTS HERE!!!

[dazzlingleon93]

hey this chemistry 2oo9 JAN 3B paper did anyone do it???please tell me hw to question 3(a) and 3d(ii ) and(iii) and (iv) (v) AND (VI) ALSO!!
so if anyone did it>>>>>>do post it up here>>>>i would really appreciate it



thankssssss

[sweetie]

ok my bad...
that four kinda vanishes...ill do it agn..i must've made a mistake in a hurry
ill check

nid cud u plz show it again???

[nid404]

nid cud u plz show it again???

tom...i have to hurry to bed now..srry
tom definitely

[sweetie]

more Que's in chem.
may02, P1 (CIE)
Q6,21,11

[The SMA]

just askin' whether if you guys knew where to get a
copy of 9701 As/A level Chemistry PastPapers book online
(the one with fully explained solution) preferably topic-by-topic.
Really wish to buy the book so it could aid me in my upcoming exams.

and By the way, i have chemistry pastpapers book actually,
but its a different syllabus code 9258 (Singapore's syllabus maybe)
n i thought that it would be an alien to CIE. does it do any good?

one more thing, guys, if u happens to have very useful chemistry revision
notes could u share them with me pleaaaase?

help me in here guys, will really appreciate it

[nid404]

more Que's in chem.
may02, P1 (CIE)
Q6,21,11

Q6) P1V1+P2V2= P3V3
     he (1X2) + ne (2X1)= x X 3
     x= 4/3
     
A

What you do is take a V3= 3dm3 (1dm3 of he and 2 dm3 of ne..since they are connected)

Q11) C

It will keep increasing as more products are formed...later, reactants act as a limiting agent...
If you are wondering why the curve can't plateau out, it is because no more substrate has been added to keep the rate constant....as the conc of substrate falls, rate of reaction falls

Q21) You already had 6 as soon as you figure the formula...right?
        now when the haloalkane is either one of these C2H4Cl2 or C2H2Cl4 or C2H3Cl3, they could have isomers...
in C2H4Cl2  the Cl could be on each carbon or only on 1 carbon...2 possible structures
   C2H2Cl4  the Cl could be 2 on each carbon or 3 on 1 and 1 on the other
   C2H3Cl6  the Cl could be all 3 on one, or divide as 2 on 1 and 1 on the other
6+ the 3 possibilities = 9
C

[~ A.F ~]

Awesomeness Nid..

+rep.

[nid404]

 

Thank You 

[sweetie]

Thank You nid..
+rep

[nid404]

Thank You nid..
+rep

ur welcome 

[cashem'up]

hey guys when determining the number of isomers a product has is there any mathemetical way to do so( excluding the sterioisomers.........that u have to figure out) but is it possible to do so for the structural isomers........i always have hunch there must be a way

[Saladin]

There is using matices, but it will take you more time than if you simply find it out yourself and keep trying possibilities.

Hope that helps.

[nid404]

The thing is it would be a different rule for different hydrocarbons, how many can you remember?
They won't ask you very complex stuff...the ones they give are usually easy to figure, just keep their structure in mind, and visualize the possibilities...always attempt these questions in the end, you get more time to draw and figure it out then

[Sue T]

hey does any1 no wat this means:
alpha particles have discreet energy values
beta have a continuous spectrum
(it ws an answer 2 a past paper question askin bout the diff between them)

[Saladin]

alpha particles act like particles, they only last for short periods of time. Beta particles, are less ionising and thus radiates more like waves.

This is a comparison between the two:

Composition and Charge:

Alpha particles are basically helium nuclei composed of two neutrons and two protons. The protons give alpha particles a positive charge. Beta particles are fast moving electrons and are negatively charged. Gamma rays are a form of energy that is part of the electromagnetic spectrum. They are neutral.

Speed and Penetration:

Alpha particles travel at about 1/20^th the speed of light and can easily be blocked by paper. Beta particles travel almost at the speed of light and can be blocked by an aluminium sheet. Gamma rays travels at the speed of light and can only be blocked by a few centimetres of lead.

Deflection in a magnetic field:

Alpha particles are heavy and deflect very little in a magnetic field. Beta particles are lighter and have the greatest deflection in a magnetic field. Gamma rays are neutral and so do not undergo any deflection.