A chemist accidentally leaves an open beaker containing 500.0 mL of a 0.250 M Mg(NO3)2(aq) solution on a lab bench. They return a few days later to find that the volume of the solution has decreased to 100.0 mL. What is the molarity of this partially evaporated solution, assuming the solute does not evaporate

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?