What is the reason for the emission of light after the gas in a discharge tube is excited?

In numbering carbon atoms in the parent chain of a hydrocarbon, why would you number from right to left, rather than left to right

Amixture initially contains a, b, and c in the following concentrations: [a] = 0.300 m , [b] = 1.05 m , and [c] = 0.550 m . the following reaction occurs and equilibrium is established: a+2b⇌c at equilibrium, [a] = 0.140 m and [c] = 0.710 m . calculate the value of the equilibrium constant, kc.

What is the difference between a substance "getting wet" and "being dissolved" in a liquid at the particulate level?