A student was provided with a piece of chalk which has a mass of 0.327 g. The chalk was dissolved in 70.00 mL of 0.450 M HCl and then the excess HCl was titrated with NaOH solution. The volume required to neutralize the excess HCl was 31.50 mL of 0.340 M NaOH. Determine the mass percent of calcium carbonate in the chalk.