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

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Answer 1 · 2014-02-15T02:30:32

To calculate the concentration of a diluted solution, you use the formula $c_{1} V_{1} = c_{2} V_{2}$ $c_1V_1 = c_2V_2$

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.

$c_{1}$ $c_1$ = 0.250 mol/L; $V_{1}$ $V_1$ = 100 mL = 0.100 L
$c_{2}$ $c_2$ = ?; $V_{2}$ $V_2$ = 1.50 L

Step 2: Solve the formula for $c_{2}$ $c_2$ .

$c_{1} V_{1} = c_{2} V_{2}$ $c_1V_1 = c_2V_2$

$c_{2} = c_{1} \times \frac{V_{1}}{V_{2}}$ $c_2 = c_1 × V_1/V_2$

Step 3: Substitute the values and solve.

$c_{2} = c_{1} \times \frac{V_{1}}{V_{2}}$ $c_2 = c_1 × V_1/V_2$ = 0.250 mol/L × $\frac{0.100 L}{1.50 L}$ $(0.100 L)/(1.50 L)$ = 0.0167 mol/L