Why is a hot air balloon able to inflate and stay inflated? Use Charles's Law to explain what happens.

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?

What is the most common reason for matter changing its state?

Now look at the segment of the graph between the two data points marked with black squares. describe how the boiling point and melting point plots behave between these points. be as specific as possible.