Chemistry: Post your doubts here!

[Mohammed salik]

Can you give me the chemistry papers theory from 2000 to 2002 please?

I actually started from O/n 2002!!
Sorry

 

[GCE As and a level]

hey guys
how are u all?
i need a help in http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_qp_23.pdf Q3 c) , Q4 c) and f) ,Q5 c) and d)
waiting your help
thanks in advance

 

[Logitech]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w07_qp_32.pdf
In this paper in Q1b how should I know which experiment to follow?

does anyone know how to do this?

 

[abruzzi]

Ekh I'm stuck with this too :/

Please let me know if you find the solution to it

 

[salvatore]

w.r.t. H2O2 :
0.70/.05 = 1.4/1.0
7/5 = 7/5

w.r.t. H+ :
if we consider the conc of H2O2 first and compare it with rate:
0.09/0.05 = 1.8/1.0
9/5 = 9/5

it shows that the rate is changing just because of H2O2 .... which means that however much the conc of H+ changes, it won't have any effect on the rate of reaction. so wrt H+ the order of reaction is 0

Thanks a lot man, peace!

 

[daredevil]

Thanks a lot man, peace!

np!! (Y)

 

[daredevil]

Ekh I'm stuck with this too :/

it's a matter of the discharge priority stuff in electrlysis...
u know the reactivity series of metals that we did in O levels too?

so according to that, O2 is discharged in preference to SO4-2 and F- so it is discharged before F2 or SO2...
Br2 however is discharged in preference to O2.

similarly work with the reactivity series for metals... which will account for the discharge at the cathode.

 

[robinhoodmustafa]

hey guys
how are u all?
i need a help in http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_23.pdf Q3 c) , Q4 c) and f) ,Q5 c) and d)
waiting your help
thanks in advance

did my best to explain. dont mind my writing. i was writing in on 'paints'
Q3 c

4c

4f

5c

 

[Browny]

does anyone know how to do this?

Yes,just calculate.

 

[GCE As and a level]

did my best to explain. dont mind my writing. i was writing in on 'paints'
Q3 c

4c

4f

5c

really thank you for your help dont worry about the hand writing
can u plz also explain to me Q3 d) and Q 5 d)
and can u explain in more depth Q 5 C) the last step

i really appreciate your help

Wish u good luck

 

[robinhoodmustafa]

really thank you for your help dont worry about the hand writing
can u plz also explain to me Q3 d) and Q 5 d)
and can u explain in more depth Q 5 C) the last step

i really appreciate your help

Wish u good luck

Mole ratio is 1:1
so each mole of C3H6O3 will give 1 mole of H2
so you have mass of C3H6O3 so calculate moles and multiply it by 24000 so calculate volume of gas
See, 1 Moles occupy 24 dm3 (24000 Cm3) so you can even apply the cross wala method.
1 --- --------24000
6.67*10^3 -----x

x= 160 cm3



alcohols have hydrogen bonding between O and H so that it why they are polar and Hydrogen bond is stronger to hold the liquid particle while the DME gas compound has weak vander waals


and sorry i m weak in ester isomer. need to work on it

pls do pray for me.

 

[GCE As and a level]

hey guys
how are u all?
i need a help in(unsolved questions) and can u check the solved questions to me?

waiting your help
thanks in advance

 

[GCE As and a level]

Mole ratio is 1:1
so each mole of C3H6O3 will give 1 mole of H2
so you have mass of C3H6O3 so calculate moles and multiply it by 24000 so calculate volume of gas
See, 1 Moles occupy 24 dm3 (24000 Cm3) so you can even apply the cross wala method.
1 --- --------24000
6.67*10^3 -----x

x= 160 cm3



alcohols have hydrogen bonding between O and H so that it why they are polar and Hydrogen bond is stronger to hold the liquid particle while the DME gas compound has weak vander waals


and sorry i m weak in ester isomer. need to work on it

pls do pray for me.

Thank you,
Can u plz also check my other doubt ???
Wish u good luck

 

[GCE As and a level]

Mole ratio is 1:1
so each mole of C3H6O3 will give 1 mole of H2
so you have mass of C3H6O3 so calculate moles and multiply it by 24000 so calculate volume of gas
See, 1 Moles occupy 24 dm3 (24000 Cm3) so you can even apply the cross wala method.
1 --- --------24000
6.67*10^3 -----x

x= 160 cm3



alcohols have hydrogen bonding between O and H so that it why they are polar and Hydrogen bond is stronger to hold the liquid particle while the DME gas compound has weak vander waals


and sorry i m weak in ester isomer. need to work on it

pls do pray for me.

inshallah u will get the highest grade in all your subjects

 

[robinhoodmustafa]

hey guys
how are u all?
i need a help in(unsolved questions) and can u check the solved questions to me?

waiting your help
thanks in advance
View attachment 40989 View attachment 40990 View attachment 40991 View attachment 40992

you need it explained ?

 

[Someone2]

hey guys
need help on Oct'12 paper 51 qs 1... can someone pls post a diagram for qs 1(d)??

Thanx

 

[GCE As and a level]

you need it explained ?

The un solved questions yes plz , while the solved questions check if they are correct , if no then plz explain them

Wish u good luck

 

[thats_me]

it's a matter of the discharge priority stuff in electrlysis...
u know the reactivity series of metals that we did in O levels too?

so according to that, O2 is discharged in preference to SO4-2 and F- so it is discharged before F2 or SO2...
Br2 however is discharged in preference to O2.

similarly work with the reactivity series for metals... which will account for the discharge at the cathode.

Could you by any chance explain this in terms of the electrode potential?
As in what are the equations for hydrogen & oxygen & do we need to change the sign for the electrode potential if the equation is reversed I.e in oxidation form?

 

[Batguy]

 

[Batguy]

HELP MEEE