[KH502]

I'm a bit stuck on this question which should be quite easy to solve, I think. I'm thinking of solving the task by finding moles/litres of NaOH solution, and then use dilution formula c1 * v1 = c2 * v2. But I find it hard to convert from % to molar concentration. Is this the wrong way to do it? Anybody who can help?

Question:
What is the molar concentration of sodium hydroxide solution when 1mL of 1% solution of
NaOH (assume that density of this solution is 1g/mL) was mixed (fill up) with water in the
volumetric flask to give 0.1 L (final volume)?

[mjc123]

Unless otherwise specified, % as a unit of aqueous solution concentration usually means g solute in 100 mL solution. So 1% NaOH is 1g NaOH per 100 mL - which can be easily converted into mol/L.

[KH502]

Thank you! My mistake was not thinking that the % equals the same molarity regardless of volume. I tried to calculate with g/mL etc. and got strange numbers because of all the conversion. Thanks