Anyone understand how to do this question?

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(> h3o^+(aq)+ch3coo^-(aq)

Which is the solubility product expression for caf2(s)?  [ca2+]/[f–]2  [ca2+][f2–]  [ca]+[f]2  [ca2+][f–]2

In an exothermic reaction, energy may be released to the surroundings in the form of question 4 options: heat light thermal all of the above