Whenever an excited hydrogen atom returns from an excited state to its ground state, it?

What is the mass of 4 molecules of co2

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

Which statement is true about this reaction? 14n+1h 15o it is a practical source of energy on earth. it occurs only outside the solar system. its product is heavier than each of its reactants. it shows the critical mass of an element.