Final answer:
The concept being assessed is the conservation of atoms in chemical equations. Equations b and c from the provided examples are balanced, conforming to the conservation of mass by having equal numbers of each type of atom on both sides, whereas equation a and the example of H₂ + O₂ → H₂O are not balanced.
Step-by-step explanation:
The question presented pertains to the conservation of atoms in chemical equations. To ensure conservation of atoms, each element must have the same number of atoms on the reactant side as on the product side. Let's look at the provided equations to determine which ones are balanced, meaning they follow the law of conservation of mass:
- a. 2Hg (l) + O₂(g) → Hg₂O₂ (s) - This equation does not conserve the number of oxygen atoms on both sides and is therefore not balanced.
- b. C₂H₂(g) + 2O₂(g) → 2 CO₂(g) + 2 H₂O(g) - This equation is balanced, as there are equal numbers of carbon, hydrogen, and oxygen atoms on both sides.
- c. Mg(NO₃)₂ (s) + 2 Li(s) → Mg(s) + 2 LiNO₃ (s) - This equation is also balanced as the number of magnesium, nitrogen, oxygen, and lithium atoms are the same on both sides of the arrow.
An example of an unbalanced equation is H₂(g) + O₂(g) → H₂O(l), where the oxygen atoms are not conserved.