Calculating percent by mass
A 1.248 g sample of limestone rock is pulverized and then treated with 30.00 mL of 1.035 M HCl solution. The excess acid then requires 11.56 mL of 1.010 M NaOH for neutralization.
Calculate the percent by mass of calcium carbonate in the rock, assuming that it is the only substance reacting with the HCl solution.