Chemistry: Post your doubts here!

[msohiabch]

for Chemistry?

yeah for chemistry paper 12 which i gave..

 

[Duamask]

yeah for chemistry paper 12 which i gave..

HOW WASS ITTT???? :O

 

[busy bee]

is ur ppr ovr??

no i still have 3 hrz .

 

[busy bee]

hmm it was good. not very difficult nor easy. you can say and average paper. i suppose that gt for this one would be round about 30 .
i got 2 3 mcqs wrong...

oh okay okay
anyways best of luck

 

[msohiabch]

HOW WASS ITTT???? :O

i already gave your ans before...

 

[MysteRyGiRl]

no i still have 3 hrz .

yea me 2

 

[MysteRyGiRl]

Which factor helps to explain why the first ionisation energies of the Group I elements decrease
from lithium to sodium to potassium to rubidium?
A The nuclear charge of the elements increases
B the outer electron is in the s subshell
C repulsion between spin paired electrons increases
D shieldng efect of inner electrons increases
answer is D bt shouldnt it b C???

can any1 explain me dis plz?

 

[busy bee]

can any1 explain me dis plz?

atomic size increases down the group
as more shells are present the sheilding effect of the electrons increases

 

[Nab900]

22 On strong heating a hydrocarbon produces ethene, propane and but-1-ene in the mole ratio 5 : 1 : 1.
What is the molecular formula of the hydrocarbon?
A C17H34
B C17H36
C C19H38
D C19H40

can someone plz explain me this??

 

[busy bee]

22 On strong heating a hydrocarbon produces ethene, propane and but-1-ene in the mole ratio 5 : 1 : 1.
What is the molecular formula of the hydrocarbon?
A C17H34
B C17H36
C C19H38
D C19H40

can someone plz explain me this??

is the ans b ?

 

[Nab900]

ya
but how???

 

[Nab900]

is the ans b ?

plz explain this question

 

[busy bee]

ya
but how???

write down the molecular formula of ethene, propane and but-1-ene
then it says the ratio is 5:1:1 so multiply the molecular formula of ethene with 5 since the other ratio is 1 so we dont not need to multiply it , after multiplyin add all carbon u ll get 17 and add all hydrogen u ll get 36 so the formula is C17H36

 

[PhoenixAsh12]

Does anyone have any AS chemistry practical tips? Exam's tomorrow...
Thanks!

 

[Nab900]

write down the molecular formula of ethene, propane and but-1-ene
then it says the ratio is 5:1:1 so multiply the molecular formula of ethene with 5 since the other ratio is 1 so we dont not need to multiply it , after multiplyin add all carbon u ll get 17 and add all hydrogen u ll get 36 so the formula is C17H36

thnx
very helpful

 

[Muhammad Asif]

How was todays paper every1????

 

[Most_UniQue]

How was todays paper every1????

Good. Easier

 

[Most_UniQue]

for Chemistry?

For chemistry , the most important thing is you have to study the book and get the concepts clearly especially organic.

 

[JD REBORN]

In chemsitry paper 12 today does anybody remember the answer to the 7 question about the equation at equilibrium.And also the question about the structure of C8H16Br2 what were the right options?

 

[angelicsuccubus]

In chemsitry paper 12 today does anybody remember the answer to the 7 question about the equation at equilibrium.And also the question about the structure of C8H16Br2 what were the right options?

for 7 I chose B.. umm adding steam I think?
and the cracking one.. I went with C.. I think it was W and X.
But then you can ignore me cause I had a horrible paper *shrug*