Help Pls pls I will give brainlist

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)

What is the percent by mass of oxygen in fe2o3

Use the periodic table to find the molar mass of each element. molar mass h = g/mol molar mass s = g/mol molar mass o = g/mol