Stoichiometry

A student conducts an experiment to determine the molarity of a $\ce{K2CO3}(aq)$ solution of unknown concentration. The student mixes $100.\; \text{mL}$100, point, start text, m, L, end text of the solution with excess $\ce{CaCl2}(aq)$, causing $\ce{CaCO3}(s)$ to precipitate. The student then filters and dries the precipitate and records the data in the table below. (The molar mass of $\ce{CaCO3}$ is $100.\; \text{g/mol}$100, point, start text, g, slash, m, o, l, end text.)