Answer
The volume required to prepare that solution using a $6.00$ $M$ $KNO_3$ solution is equal to 0.833 mL.
Work Step by Step
1. Write the dilution expression, and rearrange it to solve for "$V_1$":
$C_1V_1=C_2V_2$
- Divide both sides by "$C_1$":
$V_1 = \frac{C_2V_2}{C_1}$
2. Substitute the given values, and calculate the value of the initial volume.
$V_1=\frac{(0.250 \space M)(20.0 \space mL)}{6.00 \space M}$
$V_1 = 0.833 \space mL$