Choose the chemical equation that is correctly balanced. 2Ca(s) + Cl2(g) → CaCl2(s) 4Mg(s) + O2(g) → 2MgO(s) Li(s) + Cl2(g) → 2LiCl(s) C(s) + O2(g) → CO2(g)

Last option C(s) + O2(g) → CO2(g)

Explanation:

The reactions are:

2Ca(s) + Cl2(g) → CaCl2(s)

4Mg(s) + O2(g) → 2MgO(s)

Li(s) + Cl2(g) → 2LiCl(s)

C(s) + O2(g) → CO2(g)

Let's count the atoms (check out the stoichiometry):

1. We have 2 Ca in reactant side and 2Cl, in product side we have 1 Ca and 2 Cl. UNBALANCED

2. We have 4 Mg in reactant side and 2 O. In product side we have 2 Mg and 2 O. UNBALANCED

3. In reactant side we have 1 Li and 2 Cl. Then, in product side we have 2Li and 2Cl. UNBALANCED

C(s) + O2(g) → CO2(g)

1 C and 2 O ⇒ 1 C and 2 O         Correctly balanced