Chemistry Forum

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.

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.

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.

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.