Final answer:
In a double replacement reaction, the cations and anions of the reactants switch partners to form the products. (a) MnCO3(s) + HI(aq) will form MnI2 and CO3^2-. (b) CoO(s) + O2(g) will form CoO2. (c) La(s) + O2(g) will form La2O3.
Step-by-step explanation:
In a double replacement reaction, the cations and anions of the reactants switch partners to form the products. Let's predict the products of each reaction:
(a) MnCO3(s) + HI(aq): The cation Mn2+ from MnCO3 will pair with the anion I- from HI to form MnI2. The other product will be a spectator ion, CO32-.
(b) CoO(s) + O2(g): The reactant CoO is a metal oxide, so it will react with oxygen to form a metal oxide product. The balanced equation is 2CoO + O2 → 2CoO2.
(c) La(s) + O2(g): Similar to the previous reaction, La is a metal and will react with oxygen to form a metal oxide product. The balanced equation is 2La + 3O2 → 2La2O3.