Question

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: \[ {Zn} + {H}_3 {PO}_4 \rightarrow {Zn}_3 {(PO}_4{)}_2 + {H}_2 \]

Hint:

Always balance the atoms of each element on both sides of the equation to ensure mass is conserved during a chemical reaction.

Answer 1

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.