3. Solving a chemistry problem

194. Calculate the mass fraction in % of calcium oxide in the sample if a sample of 1.4055 g was dissolved in a volumetric flask with a capacity of 250.00 cm3. For titration of 25.00 cm3 of the prepared solution, 18.15 cm3 of a complexone III solution (the titer of which is 0.037800) was spent. M.r. CaO=56.00, M.r. complexone III=372.24.