Two mole of an ideal gas is subjected to isothermal expansion from $\pu{2 atm}$ to $\pu{1 atm}$ at $\pu{300 K}$. Calculate entropy change of the system, surrounding and total, if the process is irreversible. Since $$ΔS_\mathrm{system} = nR\ln\left(\frac{P_1}{P_2}\right),$$ I got the $ΔS$ f...

I am trying to find the color of an organic molecule, crystal violet, theoretically. I suspect that the color is due to the large conjugated system. My question is, how would I go about finding the energy levels of such a system? I know how to solve the Schrodinger equation for a particle in a ...

I was thinking of the "particle on a ring" problem as a subdivision of a bigger problem, i.e. the hydrogen atom. While in the hydrogen atom problem, the Hamiltonian contains a potential energy term, the Hamiltonian in the "particle on a ring" problem does not. Why is it so? What are its implicat...