How many grams of NaCl should be added to 4.78 kg of water if a 6.48m solution is needed?

Answer 1

Start with the equation for molality: molality = moles of solute / mass of solvent

Rearrange this to solve for moles of solute: moles of solute = molality * mass of solvent

moles of solute = 6.48m * 4.78kg = 30.97 moles

Finally, convert moles to grams: 58.44(g/mol) * 30.97mol = 1810 grams.

Answer 2

Hi Kaela M.,

So use the definition of molality = moles of solute:kg of solvent (here, water). You also will need to calculate or look up the molar mass of NaCl -- think you can handle that? Then convert the number of moles of NaCl in to mass in grams, using that molar mass. P.S. Why exactly did that require a question? Are you keeping up-to-date on your curriculum (textbook or workbook) reading?

-- Cheers, --Mr. d.