Question

10% (m/m) sodium hydroxide solution, NaOH, is used to break down wood fibre to make paper.

a) What mass of solute is needed to make 250mL of 10% (m/m) solution?

b) What mass of solvent is needed?

c) What is the molare concentration?

Answer 1

This question can't be answered exactly without knowing the density of q 10%(m/m) solution. That density based on the table at:
http://www.chembuddy.com/?left=CASC&right=density_tables
is 1.1111 g/ml. Use this density to find the mass of 250 mls.
(a) Calculate the mass of solute (10% of the mass of the solution).
(b) Find the mass of solvent (90% of the mass of the solution)
(c) Convert the mass of solute to moles by dividing it by the molar mass of NaOH.Then divide by 0.250 L to get the molar concentration.