How much energy is produced when 13.1 g of tin reacts with 2.715 g of N2 ? 3 Sn + 2 N2-Sn3N4 + 632 KJ
Hint change grams to moles first.
1 mole Sn= 1199
1 mole N2= 28 g

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?