100 g of marble were dissolved in an excess of hydrochloric acid. After the reaction

100 g of marble were dissolved in an excess of hydrochloric acid. After the reaction, 15 g of insoluble matter remained. Mass fraction of non-carbonate impurities is …

Let’s write the reaction equation:

CaCO3 + 2HCl = CaCl2 + CO2 ↑ + H2O

As can be seen from this equation, no insoluble products are formed during the reaction.

Thus, all of the insoluble residue after the reaction is non-carbonate impurities.

Mass fraction of non-carbonate impurities in marble:

w (impurity) = (m (impurity) / m (marble)) * 100 = (15/100) * 100 = 15 (%)