[Thomas]

Hi,

If I'm given two densities (one is of NaCl in water, the other is water,) how can I determine the mass fraction and mol % of NaCl in water?

[Borek]

You mean like water is 1 g/mL and some NaCl solution is 1.1 g/mL and what is NaCl concentration? Only using density tables. The fastest approach will be to use CASC concentration calculator - but it does the same thing, just the density table is built into the program.

OTOH - what do you mean by mass fraction? Percentage w/w? And by the mol %? Molar fraction sounds closest.

[Thomas]

No, I'm given the densities of both water (g/cm^3) and NaCl dissolved in water (g/cm^3.) I'm trying to find the mass fraction (mass of NaCl/total mass of solution) and mol % (mol of NaCl/total mol of solution x 100.)

Any ideas?

[Borek]

Sorry, no idea about what do you mean by density of

NaCl dissolved in water (g/cm^3.)

You may have either density of the solution, or density of NaCl crystals. Tertium non datur