Question

You add 21.00 ml of a 1.50 m solution to a 100 ml volumetric flask and then fill the flask with water to the 100 ml mark. what is the resulting concentration of sodium phosphate in molarity?

Answer 1

The new concentration of sodium phosphate is 0.315 mol·L⁻¹.

We can use the dilution formula :

c₁V₁ = c₂V₂

We can rearrange the formula to get

c₂= c₁ × (V₁/V₂)

∴ c₂ = 1.50 mol·L⁻¹ × (21.00 mL)/(100.0 mL)] = 1.50 mol·L⁻¹ × 0.2100

= 0.315 mol·L⁻¹