One half of a balanced chemical equation is shown.3Mg(OH)2 + 2H3PO4Which lists the numbers of each atom the other half of the equation would contain?

Count the atoms on the shown side: 3Mg(OH)2 contains 3 Mg, 6 O, and 6 H. The 2H3PO4 contains 2 P, 8 O, and 6 H. Altogether, that is 3 Mg, 2 P, 14 O, and 12 H, so the other side must contain the same totals in a balanced equation. This matches choice A.

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