Question

If 69 g ethanol is dissolved in 250 g of water. What is the molality of solutions

Answer 1

Answer:

molality =  (moles of [solute])/(kilograms of [solvent])

Ethanol = C2H5OH

Therefore, Molecular mass = (24 + 5 + 16 +5) = 50

 moles of Ethanol = (0.69/50)  =0.0138 moles

moles of water = (250/18) = 13.88 moles

Kilograms of H₂O = (250 g H₂O)/ (1000) =0.400 kg H₂O

molality = (moles of solute)/(kilograms of solvent)

= (0.0138 mol)/( 0.400)

= 0.0345 mol/kg