# How to calculate concentration of solution when it's diluted?

Feb 15, 2014

To calculate the concentration of a diluted solution, you use the formula ${c}_{1} {V}_{1} = {c}_{2} {V}_{2}$

Example

Calculate the concentration of NaCl if enough water is added to 100 mL of a 0.250 mol/L sodium chloride solution to make 1.50 L of dilute solution.

Step 1: Make a table of the data.

${c}_{1}$ = 0.250 mol/L; ${V}_{1}$ = 100 mL = 0.100 L
${c}_{2}$ = ?; ${V}_{2}$ = 1.50 L

Step 2: Solve the formula for ${c}_{2}$.

${c}_{1} {V}_{1} = {c}_{2} {V}_{2}$

 c_2 = c_1 × V_1/V_2

Step 3: Substitute the values and solve.

 c_2 = c_1 × V_1/V_2 = 0.250 mol/L × $\frac{0.100 L}{1.50 L}$ = 0.0167 mol/L