AS Chemistry P2 Prep.

[angelgirl:)]

Does anyone know the syllabus for AS ?

its there on the papers coulmn of this site...for 2012

 

[angelgirl:)]

ok have 1 doubt..
all grpI MNO3 decompose to MNO2 + O2
but Li haas high polarising power so it decompose like grpII M(NO3)2............... LNO3 ---->MO2 +NO2 or MO2 +NO2 +O2 as well...?
do Li on decomposition releases O2 or not ? dats my doubt...

ppl any1 know it?

 

[DragonCub]

Check nov 2006 p2 last question and the mark scheme you will get it then, even REFLUX can be used in this ......

Oops... It also says "room temperature". Heat is not necessary.

 

[Muhammad Ahmer Ali]

To chat and discuss answers pls join my group at http://xat.com/ChemPaper

 

[Muhammad Ahmer Ali]

Oops... It also says "room temperature". Heat is not necessary.

But is also says heat so it can be anything

 

[DragonCub]

ok have 1 doubt..
all grpI MNO3 decompose to MNO2 + O2
but Li haas high polarising power so it decompose like grpII M(NO3)2............... LNO3 ---->MO2 +NO2 or MO2 +NO2 +O2 as well...?
do Li on decomposition releases O2 or not ? dats my doubt...

Yeah, Lithium is polarising enough to form lithium oxide after decomposition.
4LiNO3 = 2Li2O + 4NO2 + O2

 

[Saad (سعد)]

Does anyone have a Summary or something of Inorganic Chemistry reactions? I found one of Organic Chem., so one of Inorganic Chemistry would be useful.

 

[angelgirl:)]

Yeah, Lithium is polarising enough to form lithium oxide after decomposition.
4LiNO3 = 2Li2O + 4NO2 + O2

so it means O2 is also formed....ok

 

[AngelColdplay]

http://www.xtremepapers.com/papers/... AS Level/Chemistry (9701)/9701_w11_qp_21.pdf
For question 3 d, how do you draw the Hess Law diagram? It doesn't seem to work out when I try using both diagrams in the coursebook for enthalpy change of reaction and combustion.​

 

[saudha]

ok there is this q.... where phosphorus has a greater ionisation energy than sulfur ..and q is why?
the ans is:for S one 3p orbital has paired electrons and for P 3p sub-shell is singly filled
paired electrons repel ....
i dont undersand it...explain plsssss

 

[DragonCub]

ok there is this q.... where phosphorus has a greater ionisation energy than sulfur ..and q is why?
the ans is:for S one 3p orbital has paired electrons and for P 3p sub-shell is singly filled
paired electrons repel ....
i dont undersand it...explain plsssss

Paired electrons repel, so they have higher energy and are thus more easily removed. Phosphorus has its 3p orbital just half-filled, which is relatively stable. Sulphur has one paired electrons in 3p. The paired electrons shall have slightly higher energy, so it requires less energy to remove the outermost electron from sulphur.

 

[angelgirl:)]

It requires less energy to remove and electron from paired orbital because of the repulsion between them. When you remove an electron from a singly filled orbital more energy is required as there is no repulsion to partially cancel out the attraction between the nucleus and the e-.

wen e- r paired they have spin pairing...so 1 is rotating in clockwise direction and the other in anticlockwise direction...so they should have attractive force...isnt it?

 

[Ammirul Shafiq]

ok there is this q.... where phosphorus has a greater ionisation energy than sulfur ..and q is why?
the ans is:for S one 3p orbital has paired electrons and for P 3p sub-shell is singly filled
paired electrons repel ....
i dont undersand it...explain plsssss

S has one 3p orbital has paired electrons and the paired electrons repel.When the electrons repel,the electrons get further from nucleus,thus lower ionisation energy.
P sub-shell is singly filled,there is no paired of electrons.thus the distance is nearer to the nucleus.so,higher ionisation energy

 

[Sana101]

In the nucleophilic substitution reaction of an Halogenoalkane to an alcohol, my book says the condition is 'heat under reflux!' but all the marking schemes just say 'heat!' Which one is it?

 

[DragonCub]

In the nucleophilic substitution reaction of an Halogenoalkane to an alcohol, my book says the condition is 'heat under reflux!' but all the marking schemes just say 'heat!' Which one is it?

"heat under reflux" should be more reliable. Small-molecule halogenoalkanes are usually in gaseous phase under room temperature. Reflux can ensure that the haloalkane is kept inside the container during the entire reaction.

 

[angelgirl:)]

In the nucleophilic substitution reaction of an Halogenoalkane to an alcohol, my book says the condition is 'heat under reflux!' but all the marking schemes just say 'heat!' Which one is it?

just right heat...thats better

 

[littlecloud11]

wen e- r paired they have spin pairing...so 1 is rotating in clockwise direction and the other in anticlockwise direction...so they should have attractive force...isnt it?

like charges never attract. the spin-pair repulsion merely reduces the repulsive forces between the electrons so that they can occupy the same sub-shell.

 

[Saad (سعد)]

Does anyone have a Summary or something of Inorganic Chemistry reactions? I found one of Organic Chem., so one of Inorganic Chemistry would be useful.

No one?

Also,

Paper: Click Me
Mark Scheme: Yeah, Click Him, Why Dontcha'?

Question 3; the whole question. Someone please explain it to me in detail. Jazak Allah Khayr.

 

[jsg]

http://www.xtremepapers.com/papers/... AS Level/Chemistry (9701)/9701_w11_qp_23.pdf

Help needed in Q5 part d ...

 

[saudha]

like charges never attract. the spin-pair repulsion merely reduces the repulsive forces between the electrons so that they can occupy the same sub-shell.

thxxx