potatohead

Hello everyone, I'm wondering how I would calculate the uncertainty of my findings for a lab report. I found the activation energy of the alka seltzer reaction in water (C₆H₈O₇＋3NaHCO₃ → 3H₂O＋3CO2＋Na3C6H5O7) The way I found it was to measure pressure change over time in a closed erlenmeyer flask, convert that to concentration (using ideal gas law), and take its inverse over time to graphically find the rate constant. Then, I took the natural log of the rate constant against the inverse of time (aka the Arrhenius equation) to give me Ea times r. I divided the slope of the graph by R t

Is this a good topic? If not, how can I fix it? How does the mass of x antacid (in g) affect the volume of HCl (in L) neutralized through back titration? By the way, would I need to standardize my reactants? Thanks