\( \begin{array}{l} \text { Balance this equation. }\\ -_{-} \mathrm{SnO}_{2}+{ }_{-} \mathrm{H}_{2}-{ }_{--} \mathrm{Sn}+{ }_{-} \mathrm{H}_{2} \mathrm{O} \end{array} \)

Sure, let's balance the chemical equation step by step. **Unbalanced Equation:** \[ \mathrm{SnO}_2 + \mathrm{H}_2 \rightarrow \mathrm{Sn} + \mathrm{H}_2\mathrm{O} \] **Step 1: Balance the Tin (Sn) Atoms** - **Left Side:** 1 Sn atom in \(\mathrm{SnO}_2\) - **Right Side:** 1 Sn atom in \(\mathrm{Sn}\) Tin is already balanced. **Step 2: Balance the Oxygen (O) Atoms** - **Left Side:** 2 O atoms in \(\mathrm{SnO}_2\) - **Right Side:** 1 O atom in \(\mathrm{H}_2\mathrm{O}\) To balance oxygen, place a coefficient of 2 before \(\mathrm{H}_2\mathrm{O}\): \[ \mathrm{SnO}_2 + \mathrm{H}_2 \rightarrow \mathrm{Sn} + 2\,\mathrm{H}_2\mathrm{O} \] **Step 3: Balance the Hydrogen (H) Atoms** - **Left Side:** 2 H atoms in \(\mathrm{H}_2\) - **Right Side:** \(2 \times 2 = 4\) H atoms in \(2\,\mathrm{H}_2\mathrm{O}\) To balance hydrogen, place a coefficient of 2 before \(\mathrm{H}_2\): \[ \mathrm{SnO}_2 + 2\,\mathrm{H}_2 \rightarrow \mathrm{Sn} + 2\,\mathrm{H}_2\mathrm{O} \] **Balanced Equation:** \[ \boxed{\mathrm{SnO}_2 + 2\,\mathrm{H}_2 \rightarrow \mathrm{Sn} + 2\,\mathrm{H}_2\mathrm{O}} \] This equation now has the same number of each type of atom on both sides, ensuring it's balanced.