What can scientists measure to provide evidence that electrons can move from one energy level to another?

How many grams of oxygen gas are contained in a 15 l sample at 1.02 atm and 28°c? show your work.

An alpha particle is: a hydrogen atom a nucleus of helium two neutrons an electron

Calculate the h3o+ concentration in a solution of acetic acid if the concentration of molecular acetic acid present at equilibrium is 9.97x10-3 m and k for the dissociation is 1.86x10-5. ch3cooh(aq)+h2o(l)+> h3o+(aq)+ch3coo-(aq) show me how to get the answer.