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Original post by illusionz
You are correct.


Fine. But there is another question about isotopes: Why it is possible that there are atoms which have more neutrons than protons in a nucleus? in other words: How isotopes come into being?
Original post by D.Bman
Hi illusionz and Ari Ben Canaan, Thank you very much for your help indeed :smile: I really appreciated all the help you have given me :biggrin:

Illusionz can i just have confirmation for Spectra number 1 and number 5 please ?
Especially number 5 because I cant understand from the post weather it is an amine or amide ?
And can you tell me what bonds might be present in this spectra ?
Thank you very much Lads :biggrin:


I think spectrum 1 is a hydrocarbon without a C=C, O, N etc It is possible there is a halogen but you really can't tell. You would need more data to determine the structure of the compound, NMR and mass spec would be very useful.

As for 5, I do not think it is an amide as an amide C=O is generally ~1680 wavenumbers, and in any case, almost certainly below 1700. The C=O in this case is above 1700 which gives me the impression the C=O and N-H are seperate functional groups and not part of an amide.
Reply 3562
Original post by illusionz
I think spectrum 1 is a hydrocarbon without a C=C, O, N etc It is possible there is a halogen but you really can't tell. You would need more data to determine the structure of the compound, NMR and mass spec would be very useful.

As for 5, I do not think it is an amide as an amide C=O is generally ~1680 wavenumbers, and in any case, almost certainly below 1700. The C=O in this case is above 1700 which gives me the impression the C=O and N-H are seperate functional groups and not part of an amide.


Mate for number 1
Can you tell me what would be reason for the hydrocarbon to not have the C=C and O, N having looked at the spectra ?
Is it due to the peaks or something ?
Original post by D.Bman
Mate for number 1
Can you tell me what would be reason for the hydrocarbon to not have the C=C and O, N having looked at the spectra ?
Is it due to the peaks or something ?


Because the spectrum doesn't have peaks in the regions these bonds cause peaks to appear.
Hey Everyone :biggrin:
Can someone help me with a chemistry question :tongue:

I need to draw just one mechanisms for

Nitration of Benzene
Ethane + Bromine
Ethane + Chlorine

Can someone help me draw these please :smile:

Thank you everyone :biggrin: xx
Original post by KellyRoth
Hey Everyone :biggrin:
Can someone help me with a chemistry question :tongue:

I need to draw just one mechanisms for

Nitration of Benzene
Ethane + Bromine
Ethane + Chlorine

Can someone help me draw these please :smile:

Thank you everyone :biggrin: xx


For the nitration of benzene you are essentially reacting H2SO4 and HNO3 together to produce a Nitronium ion.

Think about the interaction between the two acids.... Can you see a way by which a good leaving group (HINT: water) could be produced on the HNO3 molecule ?
Original post by Ari Ben Canaan
For the nitration of benzene you are essentially reacting H2SO4 and HNO3 together to produce a Nitronium ion.

Think about the interaction between the two acids.... Can you see a way by which a good leaving group (HINT: water) could be produced ?


Right, So im essentially reacting :
H2SO4 + HNO3 ----> Nitronium Ion ( Can you tell me the formula for this :redface: )

So after reacting H2SO4 + HNO3 would i expect to see water being produced ?
Can you correct me if am going wrong, because chemistry is my weakest subject :redface:
Also what bonding would i see in this mechanism ? xx
Original post by KellyRoth
Right, So im essentially reacting :
H2SO4 + HNO3 ----> Nitronium Ion ( Can you tell me the formula for this :redface: )

So after reacting H2SO4 + HNO3 would i expect to see water being produced ?
Can you correct me if am going wrong, because chemistry is my weakest subject :redface:
Also what bonding would i see in this mechanism ? xx


Are you an A Level student ?

I'm sure you are aware that the electrophile is NO2+ i.e. a nitronium ion.

Essentially, what happens is that the Nitric acid takes a proton from the Sulphuric acid to produce a good leaving group (water).

What is left is the NO2+ ion.

What follows is your usual electrophilic aromatic substitution reaction.

Here, have a look at this :

mechanism.png

EDIT : The reaction equation is
HNO3 + 2H2SO4 ---> 2HSO4- + NO2+ + H3O+
(edited 11 years ago)
Original post by Ari Ben Canaan
Are you an A Level student ?

I'm sure you are aware that the electrophile is NO2+ i.e. a nitronium ion.

Essentially, what happens is that the Nitric acid takes a proton from the Sulphuric acid to produce a good leaving group (water).

What is left is the NO2+ ion.

What follows is your usual electrophilic aromatic substitution reaction.

Here, have a look at this :

mechanism.png

EDIT : The reaction equation is
HNO3 + 2H2SO4 ---> 2HSO4- + NO2+ + H3O+


Ah I see, it now makes sense :biggrin:
I understand now that you've added a diagram in, and i can understand whats going on the reaction
And yes i am doing a levels, its just i find chemistry a bit tricky :redface:

One thing I am confused about is what type of reaction is it ?
Is it electrophilic aromatic substitution like you have stated above ?
And what type of bonding is going on in this mechanism ?
x
Original post by KellyRoth
Ah I see, it now makes sense :biggrin:
I understand now that you've added a diagram in, and i can understand whats going on the reaction
And yes i am doing a levels, its just i find chemistry a bit tricky :redface:

One thing I am confused about is what type of reaction is it ?
Is it electrophilic aromatic substitution like you have stated above ?
And what type of bonding is going on in this mechanism ?
x


The initial interaction between the two acids is a classic acid base reaction. Can you see how the Sulphuric acid donates a proton to the Nitric acid ? We then have a loss of water, which is secondary.

What follows is an electrophilic aromatic substitution.

Type of bonding ? What do you mean ?
Original post by Ari Ben Canaan
The initial interaction between the two acids is a classic acid base reaction. Can you see how the Sulphuric acid donates a proton to the Nitric acid ? We then have a loss of water, which is secondary.

What follows is an electrophilic aromatic substitution.

Type of bonding ? What do you mean ?


Oh Right, So we first have an acid base reaction with a proton being donated to the nitric acid. Then a loss of water occours, which is secondary. Then electrophilic subsitution.
I understand it now :smile:

Ben Canaan, I was asked in the question to analyse the type of reaction in each case in relation to its bonding.
This is the part where i am confused on, Can you help me please ?
x
I'm back!

I have discussed the fusion between Uranium and Deuterium in the physics society. During the discussion I have read that Uranium and Deuterium applies an energy bonding to become to Plutonium. Why energy come into being during the bonding between Uranium and Deuterium? I suppose that Uranium and Deuterium have to get a stimulated state to come to a bonding, as atoms keep the low-energy state by nature. And when atoms attend a bonding, they are stimulated. That is my supposition.
Reply 3572
Name: Aleisha Cullen
Hobbies : singing, sport listening to music
studying: AS chemistry, RS, psyschology and English literature
live: westmiddlands
why i like chemo: its logical and interesting
Reply 3573
please help me with this question !!!

Given that
p(g) + 3Cl(g) = PCl3 (g) energy change = -983kjmol-1
P(s) + 3/2Cl2(g) = PCl3(g) energy change = -305kjmol-1
p(s) = p(g) energy change = +314kjmol-1

Calculate the following bond energies:
a) P-Cl in PCl3

b) Cl-Cl in Cl2

I really have no clue on how to do this so please help :s
Original post by Aleisha1
please help me with this question !!!

Given that
p(g) + 3Cl(g) = PCl3 (g) energy change = -983kjmol-1
P(s) + 3/2Cl2(g) = PCl3(g) energy change = -305kjmol-1
p(s) = p(g) energy change = +314kjmol-1

Calculate the following bond energies:
a) P-Cl in PCl3

b) Cl-Cl in Cl2

I really have no clue on how to do this so please help :s


Hint : Enthalpy change of reaction = Energy used to Break bonds - Energy used to form bonds.
Original post by Ari Ben Canaan
Hint : Enthalpy change of reaction = Energy used to Break bonds - Energy used to form bonds.


I dont understand why enthalpy change = bonds broken - bonds formed


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Reply 3576
hi could anyone give me some advice? Basically I am considering being a pharmacist but I don't know that much about it. What different things can a pharmacist do?
Original post by tree123
hi could anyone give me some advice? Basically I am considering being a pharmacist but I don't know that much about it. What different things can a pharmacist do?


Hey! You'd probably be better suited to looking around in and maybe starting a thread in this forum. You're more likely to get an informed reply there.
Reply 3578
Original post by Loz17
Hey! You'd probably be better suited to looking around in and maybe starting a thread in this forum. You're more likely to get an informed reply there.


thankyouu! I was trying to find the right place to post it!:smile:
Reply 3579
Original post by Loz17
Hey! You'd probably be better suited to looking around in and maybe starting a thread in this forum. You're more likely to get an informed reply there.


do you know what jobs I could go into with a chemistry degree?:P

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