[MrKukk]

Cu + NO3- => Cu2+ + NO2
What is the oxidation and reduction? And why?

Thanks.  

[Nobby]

You have to check the oxidation numbers of the Elements.

Oxidation means the number gets larger and electrons are submitted

Reduction: the number gets smaller and electrons will be consumed

Check what happens with copper and the nitrate

[opti384]

First of all, do you know the concepts of oxidation and reduction?

[MrKukk]

First of all, do you know the concepts of oxidation and reduction?

No sir.

[AMEDIO]

so 1st study it properly....

[opti384]

Okay. Oxidation is the process in which there is a loss of electrons. Reduction is the process in which there is a gain of electrons. You might want to look up "oxidation number."

[LukeeeeBennett]

The best tip I can give = OIL-RIG

O xidation
I s
L ost
-
R eduction
I s
G ained

AND,memorise this.


Group 1 metals - always +1   
Group 2 metals - always +2   
Oxygen - usually -2 except in peroxides and F2O
Hydrogen - usually +1 except in metal hydrides where it is -1
Fluorine - always -1   
Chlorine - usually -1 except in compounds with O or F

[DevaDevil]

I dislike tricks like this, as much as they may seem convenient.

I agree with opti384 in that if you grasp what an oxidation number means, you will never again mix up oxidations and reductions, because a reduction actually reduces the oxidation number of your reactant, just as the word says.
oxidation is then nothing more than the reverse of a reduction.

e.g.:

Fe³⁺ + e^- --> Fe²⁺
is a reduction, because iron changes its oxidation state from +3 to +2 (reduced by 1)