Answer
The final concentration is equal to 4.50% (m/v) $K_2SO_4$.
Work Step by Step
1. Write the dilution expression, and solve for the final concentration ($C_2)$:
$C_1 \times V_1 = C_2 \times V_2$
- Now, divide both sides by "$V_2$":
$\frac{C_1 \times V_1}{V_2} = C_2$
$C_2 = \frac{C_1 \times V_1}{V_2} $
2. Substitute the values and calculate the final concentration:
$C_2 = \frac{(12.0 \% \space (m/v)) \times (15.0 \space mL)}{40.0 \space mL} = 4.50 \space \% (m/v)$
