Final answer:
The chemical equations in option b, C₂H4(g) + 2O2(g) → 2CO2(g) + 2H₂O(l), and option c, Mg(NO3)2(s) + 2Li(s) → Mg(s) + 2LiNO3(s), are balanced as the number of atoms for each element is equal on both sides of the equation.
Step-by-step explanation:
To determine if a chemical equation is balanced, the number of atoms of each element on the reactant side must equal the number of atoms of that element on the product side.
- a. 2Hg(e) + O2(g) → Hg2O2 (s) - Not balanced (oxygen atoms are not equal on both sides)
- b. C₂H4(g) + 2O2(g) → 2CO2(g) + 2H₂O(l) - Balanced
- c. Mg(NO3)2(s) + 2Li(s) → Mg(s) + 2LiNO3(s) - Balanced
The second and third equations are properly balanced: in equation b, there are four carbon atoms and eight hydrogen atoms on each side. In equation c, there is one magnesium atom, two lithium atoms, and six oxygen atoms (as part of two nitrate groups) on each side.