1) How many moles of hydrogen gas can be produced if 0.57 moles of hydrochloric acid, HCl, reacts with excess solid zinc according to the following chemical
equation?
2 HCl + Zn → Hz + ZnCl2

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?