Chemistry: Post your doubts here!

[asadalam]

Number of electrons in hydrogen chloride molecule = 18
Number of electrons in tetrachloromethane molecule = 74.
The van der Waal's forces in the second molecule is much greater.
Polarity should be used to justify higher melting point of a molecule over another only if their Mr is same or very similar.
In huge differences like this, it shouldn't be done.

Thanks a lot,can you explain this as well?

 

[fantastic girl]

Thanks a lot,can you explain this as well?

1- u can calculate the values if u want
or see , H-Cl bond is stronger than H-Br so its less likely that H-Cl bond breaks , thats means enthalphy change will be higher for H-Cl
2 - HBr is more likely to form than HI due to stronger H-Br bond than H-I nd Kp is proportional to the products so a higher value of Kp for H-Br since hydrogen bromide can form more easily than HI
3 - Cl atom is smaller than I so more force of attraction from nucleus so its not easy to remove an electron from a Cl atom.....so it has higher Ionization energy

 

[asadalam]

1- u can calculate the values if u want
or see , H-Cl bond is stronger than H-Br so its less likely that H-Cl bond breaks , thats means enthalphy change will be higher for H-Cl
2 - HBr is more likely to form than HI due to stronger H-Br bond than H-I nd Kp is proportional to the products so a higher value of Kp for H-Br since hydrogen bromide can form more easily than HI
3 - Cl atom is smaller than I so more force of attraction from nucleus so its not easy to remove an electron from a Cl atom.....so it has higher Ionization energy

Thanks!Mind explaining this one as well:

 

[fantastic girl]

Thanks!Mind explaining this one as well:

A nd B is wrong since its an electrophilic addition reaction which is undergone by alkenes
D- alkyl halide cnt form hydrogen bonds
C - its the only right one - when both Br2 in first compound nd one Br2 in second is removed it gives the same product

 

[qwertypoiu]

Thanks!Mind explaining this one as well:

These are halogenoalkanes. They undergo nuclephilic substitution.
The first compound has no hydrogen bonds with water.
When halogenoalkanes undergo hydrolysis, the halogen atoms are replaced by OH groups.
The first compound will have both its bromine atoms replaced, and the second one will have the one replaced. Both will end up with the same result.

EDIT: maybe second compound should not be called a halogenoalkane because it has OH group as well. The answer remains the same though.

 

[asadalam]

These are halogenoalkanes. They undergo nuclephilic substitution.
The first compound has no hydrogen bonds with water.
When halogenoalkanes undergo hydrolysis, the halogen atoms are replaced by OH groups.
The first compound will have both its bromine atoms replaced, and the second one will have the one replaced. Both will end up with the same result.

EDIT: maybe second compound should not be called a halogenoalkane because it has OH group as well. The answer remains the same though.

A nd B is wrong since its an electrophilic addition reaction which is undergone by alkenes
D- alkyl halide cnt form hydrogen bonds
C - its the only right one - when both Br2 in first compound nd one Br2 in second is removed it gives the same product

Thanks a lot bro/sis!Please help out in these as well:

 

[shazmina]

Help please ..........
http://postimg.org/image/8giq0huc9/full/
Ans is A

 

[The Sarcastic Retard]

Thanks a lot bro/sis!Please help out in these as well:

Q31
1) Both have proton no. = 3
2) both have electron = 2
3) neutrons of H = -2(idk about minus) and Li = 3
Ans = B

Q4
Use : P1V1/T1 = P2V2/T2 (convert Celsius to kelvin)

Q31
1) 1 UPE
2) 4 UPE
3) 2 UPE

 

[The Sarcastic Retard]

Help please ..........
http://postimg.org/image/8giq0huc9/full/
Ans is A

https://www.facebook.com/photo.php?fbid=1396324137364147&set=o.361031104008645&type=3&theater

 

[shazmina]

https://www.facebook.com/photo.php?fbid=1396324137364147&set=o.361031104008645&type=3&theater

Brother its coming as unavailable :/

 

[The Sarcastic Retard]

Brother its coming as unavailable :/

subsitute the equation for kc of the first reaction into the kc of the second reaction. product changes into reactant so the Kc (2) will be reciprocalled too and become 1/2.
then in the first equation there were 2 mol of X2Y so it was squared in the equation. in the second reaction is is just one so does not need to be squared so square root is taken on both sides of the eq.
It was posted by Daredevil..

 

[asadalam]

Q31
1) Both have proton no. = 3
2) both have electron = 2
3) neutrons of H = -2(idk about minus) and Li = 3
Ans = B

Q4
Use : P1V1/T1 = P2V2/T2 (convert Celsius to kelvin)

Q31
1) 1 UPE
2) 4 UPE
3) 2 UPE

How does Q31 3 have 2 UPE?Doesnt the ion have just 4s2?

 

[The Sarcastic Retard]

How does Q31 3 have 2 UPE?Doesnt the ion have just 4s2?

[Ar]3d2

 

[asadalam]

[Ar]3d2

How?It would have 20 electrons so wouldnt last 2 be in more stable 1s2?

 

[The Sarcastic Retard]

How?It would have 20 electrons so wouldnt last 2 be in more stable 1s2?

https://answers.yahoo.com/question/index?qid=20070115092528AAFnaDL

 

[asadalam]

https://answers.yahoo.com/question/index?qid=20070115092528AAFnaDL

We havent read this in AS :/

 

[The Sarcastic Retard]

We havent read this in AS :/

If u follow chemguide (Tim) then i guess u should have not face this problem.. Well my new school is awesome... was taught this concept at the end of Electronic concepts <3

 

[asadalam]

If u follow chemguide (Tim) then i guess u should have not face this problem.. Well my new school is awesome... was taught this concept at the end of Electronic concepts <3

I guess it makes sense though,it'll lose from the S shell first as they are paired i guess.

 

[The Sarcastic Retard]

I guess it makes sense though,it'll lose from the S shell first as they are paired i guess.

Not paired but in the furtherest principle shell... d orbitals are screeing until 2+ (that is removal of 4s2) then one will be removed from 3d3 leaving 3d2

 

[The Sarcastic Retard]

asadalam This one concept is very tricky to remember... (The first ten transitoin elements)
If u r confident check out 3d 4s concept on chemguide...
PS Only if u r confident that u are good enough to understand it coz it may tangle u...