One half of a balanced chemical equation is shown.

3Mg(OH)2 + 2H3PO4

Which lists the numbers of each atom the other half of the equation would contain?

3 Mg, 2 P, 14 O, 12 H
Mg, 2 P, 14 O, 6 H
3 Mg, 8 P, 7 O, 6 H
6 Mg, 6 P, 2 O, 12 H

1 answer

To determine the quantities of atoms in the other half of the balanced chemical equation for the reaction involving magnesium hydroxide (Mg(OH)₂) and phosphoric acid (H₃PO₄), we need to account for the number of each type of atom contributed by the reactants.

  1. Reactants:

    • From 3 Mg(OH)₂:

      • Magnesium (Mg): 3
      • Oxygen (O): 3 × 2 = 6 (because each Mg(OH)₂ has 2 oxygen atoms)
      • Hydrogen (H): 3 × 2 = 6 (because each Mg(OH)₂ has 2 hydrogen atoms)
    • From 2 H₃PO₄:

      • Hydrogen (H): 2 × 3 = 6
      • Phosphorus (P): 2 × 1 = 2
      • Oxygen (O): 2 × 4 = 8 (because each H₃PO₄ has 4 oxygen atoms)
  2. Total from reactants:

    • Magnesium (Mg): 3
    • Phosphorus (P): 2
    • Oxygen (O): 6 (from Mg(OH)₂) + 8 (from H₃PO₄) = 14
    • Hydrogen (H): 6 (from Mg(OH)₂) + 6 (from H₃PO₄) = 12
  3. Product side: From the original equation provided, we conclude that the total number of atoms must equal the product side.

Therefore, the other half of the balanced equation must have:

  • 3 Mg
  • 2 P
  • 14 O
  • 12 H

Thus, the correct answer is:

3 Mg, 2 P, 14 O, 12 H