Chemistry: Post your doubts here!

[Snowysangel]

i told you that a good reducing agent is the one which oxidises most easily. examples:
Cl- Fl- I-
in the above ions the general equation is
2Cl- -->Cl2 + 2e-
Cl- ion is more stable than I- but Fl- is more stable than Cl-. so strongest reducing agent is I-

Cl F I
none of these are oxidising agents

Na Mg Al
equation when oxidised
Na --> Na+ + e-
This is the equation of ionisation. Na ionise more readily than Mg which is ionises more readily than Al
So Na is strongest

Dude group 7 elements are oxidizing agents cause they're very easily reduced to their halides...the halides in turn are good reducing agents

 

[Suchal Riaz]

Dude group 7 elements are oxidizing agents cause they're very easily reduced to their halides...the halides in turn are good reducing agents

i meant to write 'none of them are reducing agent'

 

[Thought blocker]

https://www.xtremepapers.com/commun...sion-for-physics-and-chemistry-paper-1.33891/
Paper 1 PREPARING THINGS

 

[Snowysangel]

Suchal Riaz this one:
At a total pressure of 1 ATM, dinitrigen tetra oxide is 50% dissociated at a temperature of 60 degrees, according to the following equation:
N2O4 <---> 2NO2
What's the value if the equilibrium constant, Kp, for the reaction at 60 degrees?

 

[AnujaK]

https://sites.google.com/site/physicsfromatos/paper-3-revision
PHYSICS paper 3 notes! !

 

[raynalist]

Hiii.
plz can you help me to answer this question:
Explain in bond energy terms why the Haber process involves a high activation energy.

 

[Snowysangel]

Hiii.
plz can you help me to answer this question:
Explain in bond energy terms why the Haber process involves a high activation energy.

It involved the breakage of the triple nitrogen bond...hey is the process endothermic??

 

[Zain Javaid]

helped needed in the diagram .. please

 

[goodluckayesha]

View attachment 43334
helped needed in the diagram .. please

make a conical flask n label its capacity n place solid in it.... place a bunsen burner under it so the first step is complete
from the conical flask put a connecting tube into another conical flask with ice placed around the 2nd flask n both flasks shud have bung....2nd step complete
gas will be collected using 100cm3 gas syringe
Did u get it?

 

[Zain Javaid]

o s

make a conical flask n label its capacity n place solid in it.... place a bunsen burner under it so the first step is complete
from the conical flask put a connecting tube into another conical flask with ice placed around the 2nd flask n both flasks shud have bung....2nd step complete
gas will be collected using 100cm3 gas syringe
Did u get it?

ayesha miss we hav to liiquify gas . condenser wud b used

 

[goodluckayesha]

o s

ayesha miss we hav to liiquify gas . condenser wud b used

ok then wht will u do with ice eat it Mr Zaid

 

[roxylara]

Guys how should I prepare for the chemisyry MCQ's? Other then doing pastpapers, shall I go over the whole book 2 times At least?

 

[Zain Javaid]

ok then wht will u do with ice eat it Mr Zaid

ayesha i would rather prefer eating ice here its too hot already

 

[Zain Javaid]

by the way marking scheme also says lei dig condenser fills all the requirements here

ok then wht will u do with ice eat it Mr Zaid

 

[Layla Omar]

hey has anyone done the oct/nov 2010 variant paper 53 . q2. if you have please send me a copy of how you did it

 

[Zain Javaid]

anybdy plz help hhw to solve this log

 

[sachu06]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s13_qp_52.pdf
question numebr 1 (c) (iv)
how do you solve it
help fast!!

 

[Sean002]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s13_qp_52.pdf
question numebr 1 (c) (iv)
how do you solve it
help fast!!

Solubility of Ca(OH)2 is 1g/dm3
Mr of Ca(OH)2 is 74.1
Assume volume = 1dm3
only 1g of Ca(OH)2 able to dissolve in 1dm3 of water
mol of 1g Ca(OH)2= mass/ molar mass = 1/74.1
conc = mol / volume = (1/74.1)/1 = 0.0135 mol/dm3

 

[AbbbbY]

Just got done with this. It might help any of you like myself who left P5 to the last day. (Well, me, because I really don't care about it. It's such a tiny percentage etc).
What I noticed going through a few papers was some Q2's actually showed you how to do Q1's of other years, so I made a list of the topics asked for in each Q1 and method boldly explained in relevant Q2's.

 

[hela]

Just got done with this. It might help any of you like myself who left P5 to the last day. (Well, me, because I really don't care about it. It's such a tiny percentage etc).
What I noticed going through a few papers was some Q2's actually showed you how to do Q1's of other years, so I made a list of the topics asked for in each Q1 and method boldly explained in relevant Q2's.

Excellent summary