When a mg atom and o atom come together to form a bond to make mgo, is energy absorbed or released? how can you prove that energy was absorbed or released to form that bond?

Which formula can be used to calculate the molar mass of ammonia (nh3)? molar mass of n + molar mass of h 3 × molar mass of n + molar mass of h molar mass of n + 3 × molar mass of h 3 × molar mass of n + 3 × molar mass of h