申論題

3. A 0.6025 g sample was dissolved, and the Ca²⁺ and Ba²⁺ ions present were precipitated as BaC₂O₄ • H₂O and CaC₂O₄ • H₂O. The oxalates were then heated in the 320°C to 400°C range to produce an anhydrous residue (MC₂O4, M = Ca or Ba) that weighed 0.5713 g. Subsequently, the anhydrous residue was heated in the 580°C to 620°C range and the resulting products corresponding to the two carbonates weighted 0.4673 g finally.

(a) Write down the equations of the chemical reactions occurred in the 580°C to 620°C range. (10 pts)