Chapter 9 - Section 9.4 - Concentrations of Solutions - Study Check 9.7 - Page 298: 1

$$Mass/volume \space percent (m/v) = 5.5 \space \% \space NaOH \space solution$$

$$Mass/volume \space percent (m/v) = \frac{grams \space of \space solute}{volume \space of \space solution} \times 100\%$$ $$Mass/volume \space percent (m/v) = \frac{12 \space g \space NaOH}{220 \space mL \space solution} \times 100\%$$ $$Mass/volume \space percent (m/v) = 5.5 \space \% \space NaOH \space solution$$