Question

finding this difficult .how is this balanced.Copper nitrate crystals when heated decompose to form copper 2 oxide ,nitrogen dioxide gas plus oxygen gas.
I got CuNO3--->CuO+N2+O

Answer 1

oxygen gas exists as a diatomic molecule, O2

CuNO3 ---> CuO+N2+O2

Answer 2

Nitrogen dioxide is NO2, isn't?

Also, shouldn't the copper nitrate be Cu(NO3)2 ?

we have 1 Cu, 2 N, 6 O to use up per Cu(NO3)2

2 Cu(NO3)2 ---> 2 CuO + 4 NO2 + O2

Answer 3

damn i didn't read the question just looked at the equation, you're certainly right it should be NO2. And although copper nitrate has several formulas, it is what you wrote. It also makes sense because the equation wont balance if copper (I) nitrate is used and how there are 4 electrons transferred between N and O while everything else remains constant.

4 N^(+5) + 4e -> 4 N^(+4)
2 O^(-2) -> O2 + 4e