Chem paper 1 2008 helpp

[1992]

hello can someone solve me these few questions
its from M/J 2008 : Q2, 6, 10, 15 and 25
also O/N 2008: Q 1,2, 29 and 30. i really need to understand these questions. thanks

 

[princesszahra]

june 08
q2
find moles of nitrogen
ie 15/14
so

15/14----------------- 100g
?------------------14
u get 0.15
then
0.15 ----5dm^3
?---------1dm^3
now u get 0.03

q10
delta H nought of pdts - reactants
so
2(-110) - - 940
u get 720

 

[princesszahra]

q 25e
C and D cant be the answer cuz they r secondary and tertiary

B cant be the answer cuz OH- is an ionized one
so the answer is A

 

[intel1993]

hey princess can u help me out..................in n 2009 p12 q 22...............

why B cant be ans why C.................as the also produces diol when cold alkaline is reacted with ethene..........

 

[princesszahra]

nov 08
q1
write eqn
FeTi)3 ----------- > TiO + FeO
then moles of FeTiO3
now find!

 

[princesszahra]

@ intel 1993
nov 09 12
q22
we cant oxidize once the polymer is formed!
so B and D cant be the answers
nor we can hydrolyse the addition polymer
so A is not the answer
left C
so it is the answer !!
happy now??!

 

[intel1993]

hmmmm.no em not......ye cheez mghe kyu nahi yad ayi............loxl...

 

[princesszahra]

june 08
q 15

find mr of CaCO3 ie 100.1
nd no of moles of CaCO3 ie total mass here
take it as 1200 only
if u can put million and have time to do all that stuff do it
but here's a striaght way
then CaCO3 ----> caO +CO2
then no of moles of co2 will be same as caco3
ie 11.988
them no of moles is mass / mr
mr of co2 is 32+12=44
so 44x11.988 so u get 527 which is the answer!

 

[shooter]

Nov 2006 Paper 1 Q.11
Can anybody plz explain to me how these type of questions are done?!
Im totally getting screwed by chemistry!

 

[princesszahra]

@ shooter!
http://www.chemguide.co.uk/physical/equilibria/kc.html


HOPE THIS HELPS!

 

[shooter]

Nope, still stuck. Look, i understand the equilibrium process and how to write the equation but how do we find the moles from the Kc at equilibrium. By my method i get the wrong answer. Can u tell me the steps of your working to solve this question plz.

 

[princesszahra]

k shooter
here
c2h5oh ch3co2h ch3co2c2h5 h20
1 1 1 1 ---- equilibrium moles
1 1 0 0---------initial moles
1-x 1-x x x ---------final moles
then they told kc is 4
so x^2 / (1-x)^2 = a


x/ (1-x) =2 ( by taking square root)!
x=2-2x
3x=2
x=2/3
NOW U GET IT???

 

[shooter]

Woah! YEAH!AWESOME! I get it! Finally! Thanks princesszahra!

 

[princesszahra]

@ shooter
welcome!