Balance the equation H4N2O3 ---> N2 + H2O

I need step by steps too please:)

Sulfuric acid (a component of acid rain) reacts with limestone (calcium carbonate) to produce calcium sulfate and carbon dioxide. this damages buildings and statues made of limestone. which solution of sulfuric acid will damage these structures more quickly? a. 0.001% b. 0.005% c. 0.010% d. 0.015%

Can someone me with 1 to 4 plz. fast

Stage in which a typical star has completely stopped fusion