4.215 g of a metallic carbonate ($MCO_3$) was heated in a hard glass tube and the $CO_{2}$ evolved w

Question

4.215 g of a metallic carbonate ($MCO_3$) was heated in a hard glass tube and the $CO_{2}$ evolved was found to measure 1336 mL at $27^{\circ}C$ and 700 mm pressure. What is the equivalent weight of the metal?

Professor PC Thomas Classes · Answer

Moles of $CO_2 = PV/RT = (700/760 	imes 1.336) / (0.0821 	imes 300) = 0.05~mol$. Mass of $MCO_3$ per mole of $CO_2 = 4.215 / 0.05 = 84.3~g/mol$. Molar mass of M = $84.3 - 60 = 24.3~g/mol$. Equivalent weight = $24.3 / 2 = 12.15$.