A sample of \( \mathrm{CaCO_3} \) and \( \mathrm{MgCO_3} \) weighed \( 2.21 \, \text{g} \) is ignited to constant weight of \( 1.152 \, \text{g} \). The composition of mixture is:
(Given molar mass in \( \text{g mol}^{-1} \) \( \mathrm{CaCO_3} : 100, \; \mathrm{MgCO_3} : 84 \))