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

1 Answer
Feb 15, 2014

To calculate the concentration of a diluted solution, you use the formula 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 = 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_1V_1 = c_2V_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 × (0.100 L)/(1.50 L) = 0.0167 mol/L