When a chemical reaction takes place, the total mass of the reactants equals the total mass of the products. the total number of atoms of reactants also equals the total number of atoms of products. in the following reaction, 18g of hydrogen react completely with 633g of chlorine. how many grams of hcl are formed?

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?