Chemistry: Post your doubts here!

[FranticAmaze]

Where to study these topics from? :/

It's there in the new book
I can send pics if u need

 

[My Name]

It's there in the new book
I can send pics if u need

Where to study these topics from? :/

The new book is there on gceguide.

 

[Iris Dylan Lane]

Then why not D?

The answer is D. Two pie orbitals opting for sideways overlapping.

 

[The Sarcastic Retard]

Newly added all topics are easy

 

[Copy Cat]

 

[Copy Cat]

The answer is D. Two pie orbitals opting for sideways overlapping.

It's says B as the answer.

 

[qwertypoiu]

It's says B as the answer.

Only B shows a p orbital.

p orbitals

 

[qwertypoiu]

View attachment 59588

Formation of ICl3 (s):

1/2 I2 (s) + 3/2Cl2(g) --> ICl3(s)

2 x Formation of ICl3 (s) :

I2(s) + 3Cl2(g) --> 2ICl3(s)


How to do this?

Easy.

Atomize: I2(s) ---> I2(g) [+38]

React: I2(g) + 3Cl2(g) ---> 2ICl3 (s) [-214]

Total = 38 - 214 = -176kJ

But this was 2 x Formation of ICl3(s)

So divide it by 2. -176/2 = -88kJ/mol

 

[qwertypoiu]

View attachment 59588

Oxidation number of N in:

NH4+ : -3

NO3- : +5

N2O : +1

So change from NH4+ to N2O is +4

And change from NO3- to N2O is -4

 

[Copy Cat]

Only B shows a p orbital.

p orbitals

Formation of ICl3 (s):

1/2 I2 (s) + 3/2Cl2(g) --> ICl3(s)

2 x Formation of ICl3 (s) :

I2(s) + 3Cl2(g) --> 2ICl3(s)


How to do this?

Easy.

Atomize: I2(s) ---> I2(g) [+38]

React: I2(g) + 3Cl2(g) ---> 2ICl3 (s) [-214]

Total = 38 - 214 = -176kJ

But this was 2 x Formation of ICl3(s)

So divide it by 2. -176/2 = -88kJ/mol

Oxidation number of N in:

NH4+ : -3

NO3- : +5

N2O : +1

So change from NH4+ to N2O is +4

And change from NO3- to N2O is -4

Jazak Allah Khairan

You're a life saver!!!

I still have a few more doubts,If possible can you please solve them............

 

[qwertypoiu]

Jazak Allah Khairan

You're a life saver!!!

I still have a few more doubts,If possible can you please solve them............

Bring it on

 

[Copy Cat]

 

[qwertypoiu]

View attachment 59589 View attachment 59590

X is not a strong acid. The pH is only 6.

An alkali that has a pH of 9 dissociates to produce some OH- ions. An acid that has a pH of 6 dissociates to produce some H+ ions.

Since neutral pH is 7, and 9 is further away from 7 than 6, that means X must be dissociating less.

 

[qwertypoiu]

View attachment 59589 View attachment 59590

CaCO3 and Ca(OH)2 both react with acids. KNO3 is a salt. It is a result of neutralisation, not a reagent.

 

[qwertypoiu]

View attachment 59589 View attachment 59590

NO can be oxidised to NO2 in the atmosphere pretty easily. SO2 can also be oxidised to SO3, especially since NO catalyses this reaction.

Unfortunately, CO is quite stable and won't turn into CO2 in the atmosphere. If that was the case, we wouldn't be complaining about CO, since it would be naturally depleted. Only the CO2 produced would be an issue due to global warming.

Oxidation of NO and SO2 to form NO2 and SO3 respectively doesn't solve any problems, since it still forms acid rain and weathers the buildings and destructs aquatic life.

 

[Saad the Paki]

So the 2016 syllabus for AS has somethings moved from A2 to As, namely carbon nanotubes and Buckminsterfullerene, infrared spectroscopy and iodofrom test. I have no where to practice questions from these so could anybody link some A2 papers having questions from these topics. Cheers

 

[The Sarcastic Retard]

Muammar:) Here you go.

 

[Konstantino Nikolas]

So the 2016 syllabus for AS has somethings moved from A2 to As, namely carbon nanotubes and Buckminsterfullerene, infrared spectroscopy and iodofrom test. I have no where to practice questions from these so could anybody link some A2 papers having questions from these topics. Cheers

Iodoform test I think A2 questions should be pretty much similar to the AS ones.
Question 5 of the specimen paper http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_y16_sp_4.pdf includes iodoform test.
Question 9 of http://theallpapers.com/papers/CIE/AS_and_ALevel/Chemistry (9701)/9701_w13_qp_43.pdf includes buckminister fullerene.

 

[Copy Cat]

CaCO3 and Ca(OH)2 both react with acids. KNO3 is a salt. It is a result of neutralisation, not a reagent.

NO can be oxidised to NO2 in the atmosphere pretty easily. SO2 can also be oxidised to SO3, especially since NO catalyses this reaction.

Unfortunately, CO is quite stable and won't turn into CO2 in the atmosphere. If that was the case, we wouldn't be complaining about CO, since it would be naturally depleted. Only the CO2 produced would be an issue due to global warming.

Oxidation of NO and SO2 to form NO2 and SO3 respectively doesn't solve any problems, since it still forms acid rain and weathers the buildings and destructs aquatic life.

Thanks a bunch.

 

[Iris Dylan Lane]

http://www.chemguide.co.uk/basicorg/isomerism/cholesterol.gif
How do I identify the chiral carbon atom?
Ty in advance..