Oxidation state of Carbon in Urea

[Steelersfan2009]

I know its +4 but can someone walk me through why it is so... i'm kinda slow at figuring out oxidation states of weird stuff zzz.

http://upload.wikimedia.org/wikipedia/commons/c/c0/Urea.png

here is an image of urea.

Thanks

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[Doodl3s]

O is almost ALWAYS -2... and H is almost always +1... with that in mind, you have to figure out the N's... in order to have a full octet, they need to be -3 (and they already have +2 each from the two hydrogens...
so you have O=-2, H=+1 each (+4) , N=-3 each (-6)... SO
-2 + 4 -6 = -4... the carbon MUST be plus 4

 

[Steelersfan2009]

O is almost ALWAYS -2... and H is almost always +1... with that in mind, you have to figure out the N's... in order to have a full octet, they need to be -3 (and they already have +2 each from the two hydrogens...
so you have O=-2, H=+1 each (+4) , N=-3 each (-6)... SO
-2 + 4 -6 = -4... the carbon MUST be plus 4

excellent thanks very much