Determine o Nox

Chemistry and homework help forum.

Organic Chemistry, Analytical Chemistry, Biochemistry, Physical Chemistry, Computational Chemistry, Theoretical Chemistry, High School Chemistry, Colledge Chemistry and University Chemistry Forum.

Share your chemistry ideas, discuss chemical problems, ask for help with scientific chemistry questions, inspire others by your chemistry vision!

Please feel free to start a scientific chemistry discussion here!

Discuss chemistry homework problems with experts!

Ask for help with chemical questions and help others with your chemistry knowledge!

Moderators: Xen, expert, ChenBeier

Post Reply
lidiane
Full Member
Full Member
Posts: 15
Joined: Fri Apr 15, 2022 2:28 pm

Determine o Nox

Post by lidiane »

Como determina o nox de cada elemento deste composto?

[(CH3)2N-NH2]
User avatar
ChenBeier
Distinguished Member
Distinguished Member
Posts: 1525
Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

Re: Determine o Nox

Post by ChenBeier »

Please use english.

How do you determine o nox of each element of this compost?

But its not understandable what is meant. Can you described more in detail.
lidiane
Full Member
Full Member
Posts: 15
Joined: Fri Apr 15, 2022 2:28 pm

Re: Determine o Nox

Post by lidiane »

ChenBeier wrote: Sat Apr 16, 2022 12:15 pm Please use english.

How do you determine o nox of each element of this compost?

But its not understandable what is meant. Can you described more in detail.

Sorry, given this compound: 1,1-dimethylhydrazine, the request is to determine the nox of each element in it. Example: H = +1. My difficulty is knowing for the N and C for this more complex compound

[(CH3)2NHH2]
User avatar
ChenBeier
Distinguished Member
Distinguished Member
Posts: 1525
Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

Re: Determine o Nox

Post by ChenBeier »

You talking about oxidationnumber of the elements.
H is +1 in most compounds , -1 in hydrides like NaH.
C can be from +4 to -4 depending on partner. Elektronegativity number.
N can be -3 to + 5 depending on partner
Bonds between the same element here N is 0.

[(CH3)2N-NH2]

H is + 1
C -2 calculated as 3* (+1)H +(-1)N = +2 , what means -2 then for C.
N -2 calculated as 2* (+1)H and also 2*(+1)C = +2 what means -2 for N.
lidiane
Full Member
Full Member
Posts: 15
Joined: Fri Apr 15, 2022 2:28 pm

Re: Determine o Nox

Post by lidiane »

ChenBeier wrote: Sat Apr 16, 2022 1:42 pm You talking about oxidationnumber of the elements.
H is +1 in most compounds , -1 in hydrides like NaH.
C can be from +4 to -4 depending on partner. Elektronegativity number.
N can be -3 to + 5 depending on partner
Bonds between the same element here N is 0.

[(CH3)2N-NH2]

H is + 1
C -2 calculated as 3* (+1)H +(-1)N = +2 , what means -2 then for C.
N -2 calculated as 2* (+1)H and also 2*(+1)C = +2 what means -2 for N.
I didn't understand where these numbers that I highlighted in color came from. Could you detail this procedure?
User avatar
ChenBeier
Distinguished Member
Distinguished Member
Posts: 1525
Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

Re: Determine o Nox

Post by ChenBeier »

Start in this way. Let say you have ammonia NH3 then N is calculated 3*(+1) H = 3 what means 3 positiv charges have to compensate with 3 negative charges, so the charge is -3 for N.
Now we look on hydrazin H2NNH2. We have one N-N bond what gives 0. So we have to check the only NH2 . Like above we 2*(+1) = 2 , so the Nitrogen has to be -2 in this case.
For C I will explain with CH4, CH3Cl, CH2Cl2 CHCl3 and CCl4
In CH4 we have the same rule like with N . 4 *(+1) = 4 what means C is - 4.
CH3Cl we have 3*(+1) H + 1*(-1)Cl = +2 what means C has to be -2.
In CH2Cl2 we get 2*(+1)H + 2*(-1) Cl =0, C is 0.
In CHCl3 we get 1*(+1)H + 3*(-1) Cl = -2 , now carbon is +2
And finally CCl4 is 4*(-1) Cl = -4 what means carbon get the maximum of + 4

Now our Molecule [(CH3)2NNH2] has two Methyl groups. As we learned above CH3-Cl C got -2. Instead of the Cl we have a N what must have then also -1 like the chlorine. Each methyl group delivers +1 what gives -2 for nitrogen. So the calculation is

C -2 calculated as 3* (+1)H +(-1)N = +2 , what means -2 then for C.
N -2 calculated as 2* (+1)H and also 2*(+1)C = +2 what means -2 for N

For Methyl-amin we have 3* (+1)H plus one bond to N, what gives (-1)N = +2, carbon therefore -2.
lidiane
Full Member
Full Member
Posts: 15
Joined: Fri Apr 15, 2022 2:28 pm

Re: Determine o Nox

Post by lidiane »

ChenBeier wrote: Sun Apr 17, 2022 1:24 am Start in this way. Let say you have ammonia NH3 then N is calculated 3*(+1) H = 3 what means 3 positiv charges have to compensate with 3 negative charges, so the charge is -3 for N.
Now we look on hydrazin H2NNH2. We have one N-N bond what gives 0. So we have to check the only NH2 . Like above we 2*(+1) = 2 , so the Nitrogen has to be -2 in this case.
For C I will explain with CH4, CH3Cl, CH2Cl2 CHCl3 and CCl4
In CH4 we have the same rule like with N . 4 *(+1) = 4 what means C is - 4.
CH3Cl we have 3*(+1) H + 1*(-1)Cl = +2 what means C has to be -2.
In CH2Cl2 we get 2*(+1)H + 2*(-1) Cl =0, C is 0.
In CHCl3 we get 1*(+1)H + 3*(-1) Cl = -2 , now carbon is +2
And finally CCl4 is 4*(-1) Cl = -4 what means carbon get the maximum of + 4

Now our Molecule [(CH3)2NNH2] has two Methyl groups. As we learned above CH3-Cl C got -2. Instead of the Cl we have a N what must have then also -1 like the chlorine. Each methyl group delivers +1 what gives -2 for nitrogen. So the calculation is

C -2 calculated as 3* (+1)H +(-1)N = +2 , what means -2 then for C.
N -2 calculated as 2* (+1)H and also 2*(+1)C = +2 what means -2 for N

For Methyl-amin we have 3* (+1)H plus one bond to N, what gives (-1)N = +2, carbon therefore -2.
Thanks for the explanation. I was confused because as nitrogen is from the 5A family and tends to want 3 electrons to complete the octet, the oxidation number would be -3 and not -1, as you did in allusion to Cl, which is from the 7A family and needs only 1 electron to complete octet
User avatar
ChenBeier
Distinguished Member
Distinguished Member
Posts: 1525
Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

Re: Determine o Nox

Post by ChenBeier »

I think you dont understand the System. Of course is nitrogen still 3valent. The calculation is based on the bond. The Nitrogen bond to 2 CH3- and one bond to the other nitrogen. On the other side there 2 bonds to H and one to the first nitrogen.
But this has nothing to do with the calculation. A --NH2 is -1 like a -OH is also -1. The nitrogen is -3 and the oxygen is - 2.
lidiane
Full Member
Full Member
Posts: 15
Joined: Fri Apr 15, 2022 2:28 pm

Re: Determine o Nox

Post by lidiane »

ChenBeier wrote: Sun Apr 17, 2022 10:07 am I think you dont understand the System. Of course is nitrogen still 3valent. The calculation is based on the bond. The Nitrogen bond to 2 CH3- and one bond to the other nitrogen. On the other side there 2 bonds to H and one to the first nitrogen.
But this has nothing to do with the calculation. A --NH2 is -1 like a -OH is also -1. The nitrogen is -3 and the oxygen is - 2.
ok, thank you so much. Now i get it
Post Reply