Chemical formula and thoretical/percent yield.

2 ml of 15M Nitric acid was added to copper bromide(CuBr) and gently heated untill a black substance was formed, copper oxide(CuO), and was completly dry. There was .93g of CuO formed in the reaction. The CuO was formed from the decomposition of the copper nitrate produced by the reaction of ntitric acid with copper bromide.

I have to find the chemical formula and calculate the theoretical and percent yields.

I'm having trouble writing the chemical formula...So far i have
CuBr + HNO3 ----> CuNO3 + Br2 + H2
(I know its not balanced yet but i want to know if its right before i balance it)

and

CuNO3 + HNO3 ----> CuO + N2
(This also isnt balanced)


Do i have to combine these formulas to find a formula that models the reaction? If so, how do I do that?

 

im fairly confident that it is copper (I) bromide

 

thanks for the help :)