When a 1.000 g sample of CoCO3 is heated under vacuum, it forms 0.630 g of an oxide of cobalt. When — Stoichiometry Chemistry Question

When a 1.000 g sample of CoCO₃ is heated under vacuum, it forms 0.630 g of an oxide of cobalt. When this sample is exposed to air, it forms a second oxide of cobalt, and attains a mass of 0.675 g. What are the formulas of the first and second oxide of cobalt, respectively?