Why do we balance a chemical equation? Name and state the law that suggests the balancing of a chemical equation. Balance the following chemical equation:
\[
{Zn} + {H}_3 {PO}_4 \rightarrow {Zn}_3 {(PO}_4{)}_2 + {H}_2
\]
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Solution and Explanation
We balance chemical equations to ensure that the law of conservation of mass is satisfied. According to this law, matter cannot be created or destroyed in a chemical reaction. Therefore, the number of atoms of each element must be the same on both sides of the equation.
Balanced equation: \[ 3 \, {Zn} + 2 \, {H}_3 {PO}_4 \rightarrow {Zn}_3 {(PO}_4{)}_2 + 3 \, {H}_2 \] This balanced equation shows that 3 atoms of zinc react with 2 molecules of phosphoric acid to produce zinc phosphate and hydrogen gas.
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