490g of Na2SO4 are dissolved in 80g of water. Determine the molality of this solution

43.13mol/kg

Explanation:

since molality is the concentration of a solution in moles of solute per kilogram of solvent.

moles of Na2SO4 = mass/molar mass

= 490/142

= 3.45 mol

mass of water in kg= 80/1000

=0.08kg

molality is therefore= 3.45/0.08

=43.5mol/kg

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