Question

If you needed to make 100 mL of a 0.2 M fruit drink solution from the 1.0 M fruit drink solution, how would you do it? (Hint: Use MsVs = MdVd to find the amount of concentrated solution you need, then add water to reach 100 mL.)

Answer 1

Using equation M_sV_s = M_dV_d (where M_s - molarity of stock solution, V_s - volume of stock solution, M_d - molarity of diluted solution and V_d - volume of diluted solution) we can find V_s:

$V_s = \frac{M_dV_d}{M_s} = \frac {0.2\frac{mol}{L} \cdot 0.1 L}{1.0 \frac{mol}{L}}=0.02 L = 20 mL$

Thus, to prepare 100 mL of diluted solution we should measure 20 mL of concentrated stock solution and then add water to reach 100 mL.