Chemistry: Post your doubts here!

[strangerss]

if a hydroxyl group is in a ketone or aldehyde they have the name hydroxy for example 2-hyrdoxybutanal or 2-hyroxybutanone

THANKS A LOT

 

[strangerss]

WHICH TYPE OF INTERMolecular forces is the weakest? coz in my book its van der waals where was i my chemistry guide its permanent dipole?

 

[salvatore]

WHICH TYPE OF INTERMolecular forces is the weakest? coz in my book its van der waals where was i my chemistry guide its permanent dipole?

van der Waal's forces are the weakest because they are just induced dipoles..

 

[Soldier313]

Aoa wr wb

Can someone please help me with the diagram in qn 1 of this paper?
and qn 2, could someone please tell me what values they get for solubility?
(i used the same method indicated above by xhizors and MaxStudentALevel

......but on plotting the points i get a curve with 5 anomalies! )

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_52.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_ms_52.pdf

Thanx a lot
JazakAllah khair

 

[xhizors]

Aoa wr wb

Can someone please help me with the diagram in qn 1 of this paper?
and qn 2, could someone please tell me what values they get for solubility?
(i used the same method indicated above by xhizors and MaxStudentALevel

......but on plotting the points i get a curve with 5 anomalies! )

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_52.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_ms_52.pdf

Thanx a lot
JazakAllah khair

for plotting
yeah exactly they are not anamolies, it is curve draw a line connecting the points !

 

[MaxStudentALevel]

for plotting
yeah exactly they are not anamolies, it is curve draw a line connecting the points !

I had the same confusion!!! It's a curve!

 

[MaxStudentALevel]

its easy to think by that way!

Yes but the errors don't always involve the Y axis!

 

[MaxStudentALevel]

COULD SOMEONE MAKE A SEPARATE P5 THREAD? FOR CHEM?

 

[xhizors]

Yes but the errors don't always involve the Y axis!

No they do involve the Y-axis only
as Y-axis in independent axis
so take an eg
u collecting volume of CO2 from CuCarbonate
on x-axis Cu(CO3)2 mass
on Y-axis volume of CO2
agar u take less mass of Cu(CO3)2 u definately get less amount of CO2
but less CO2 collected than expected can be caused by many reasons like bung placed lately or timed less etc etc!!
hope that helps !

 

[MaxStudentALevel]

No they do involve the Y-axis only
as Y-axis in independent axis
so take an eg
u collecting volume of CO2 from CuCarbonate
on x-axis Cu(CO3)2 mass
on Y-axis volume of CO2
agar u take less mass of Cu(CO3)2 u definately get less amount of CO2
but less CO2 collected than expected can be caused by many reasons like bung placed lately or timed less etc etc!!
hope that helps !

It does make sense! But sometimes it says like reading taken at too high a temp (as ind) and the error would be due to not letting apparatus cool down ?

 

[Namera]

Lithium is an alkali metal – one of a group of very reactive metals which are stored under oil to prevent contact with air and water vapour.
The reaction of lithium with water can be represented by the equation below.
2Li(s) + 2H2O(l) → 2LiOH(aq) + H2(g)
(a) In the space below, draw a diagram that clearly shows the apparatus you could use to:
q react a weighed amount of lithium metal with water, q collect the hydrogen gas produced,
q measure the volume of gas produced.

Plz help!

 

[Namera]

Lithium is an alkali metal – one of a group of very reactive metals which are stored under oil to prevent contact with air and water vapour.
The reaction of lithium with water can be represented by the equation below.
2Li(s) + 2H2O(l) → 2LiOH(aq) + H2(g)
(a) In the space below, draw a diagram that clearly shows the apparatus you could use to:
- react a weighed amount of lithium metal with water,

collect the hydrogen gas produced,

measure the volume of gas produced.

Plz help!

Li is so reactive. We cannot possibly add water directly

 

[TSZ]

Hey, I have some P5 problems.
my first question is from May june 12 ppr 51. In Q1 part (c), can any one explain, in detail (as these questions always get the best of me), how to produce a saturated solution of concentration 1.39 moldm-3. Then I can handle the rest
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_qp_51.pdf
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_ms_51.pdf

My next problem is in Paper 51 of Nov 12. What I don't get is that in Q1 part (e), how will we use the results to reach a conclusion. The mark scheme says to calculate moles of Pb and O, but in metallic reduction by H2, i think water is produced and not O2, then how will we calculate moles of Oxygen. Thank you in advance

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_51.pdf
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_ms_51.pdf

 

[bravegirl123]

I need help in MCQ# 11 and 33 of this paper: http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_12.pdf

 

[knowitall10]

By the way... i was just thinking that i think many of us did numerous Paper 5's.. don't you think we must start paper4 cuz there arent many days left to revise it.. Paper 5 doesnt really affect much of the overall grade. don't you think?

 

[applepie1996]

By the way... i was just thinking that i think many of us did numerous Paper 5's.. don't you think we must start paper4 cuz there arent many days left to revise it.. Paper 5 doesnt really affect much of the overall grade. don't you think?

HA HA xD
everything helps ............whether its paper 5 or 4
besides its fine you can start practicing paper 4 after paper 5
you have a lot of time after that
in the end its your choice

 

[knowitall10]

HA HA xD
everything helps ............whether its paper 5 or 4
besides its fine you can start practicing paper 4 after paper 5
you have a lot of time after that
in the end its your choice

Yeah.. i know but after making an account here, i realized i'm actually answers to my questions by myself cuz many questions here were the ones that i always had.. but many of them are also Paper 5 questions.. my theory is not that thorough.. and i need something to boost my enthusiasm the way it did when we discussed P5's. I'm scared i wont be able to do good...
How do you manage your time equally? Any ideas?

 

[applepie1996]

Yeah.. i know but after making an account here, i realized i'm actually answers to my questions by myself cuz many questions here were the ones that i always had.. but many of them are also Paper 5 questions.. my theory is not that thorough.. and i need something to boost my enthusiasm the way it did when we discussed P5's. I'm scared i wont be able to do good...
How do you manage your time equally? Any ideas?

first you tell me what subjects you take
and then i will help you manage out
its not that difficult to handle when you have everything sorted out
InshaAllah you will do good
so i can know what exams you have on what day

 

[MaxStudentALevel]

Yeah.. i know but after making an account here, i realized i'm actually answers to my questions by myself cuz many questions here were the ones that i always had.. but many of them are also Paper 5 questions.. my theory is not that thorough.. and i need something to boost my enthusiasm the way it did when we discussed P5's. I'm scared i wont be able to do good...
How do you manage your time equally? Any ideas?

BEST way is to just go through papers 2007-2012 and if you don't have time
-just 2012-2010 is sufficient!
-Mark problem areas and review those from the book

ALSO please make a separate Chem P4 thread and we can start discussions there as well!

 

[MaxStudentALevel]

Yeah.. i know but after making an account here, i realized i'm actually answers to my questions by myself cuz many questions here were the ones that i always had.. but many of them are also Paper 5 questions.. my theory is not that thorough.. and i need something to boost my enthusiasm the way it did when we discussed P5's. I'm scared i wont be able to do good...
How do you manage your time equally? Any ideas?

Also, are you giving Physics?