Question

The molality of a solution that is made by dissolving a certain mass of ethanol in 85.4 g of water is 0.950 m. How many moles of ethanol were dissolved? Use mc028-1.jpg. 0.0811 mol 0.0899 mol 11.1 mol 81.1 mol

Answer 1

Molality = moles of solute /mass of solvent in kg = moles of solute x1000/mass of solvent in gm. Moles of solute = molality x mass of solvent /1000 = 0.95x85.4/1000= 0.0811moles.

Answer 2

The moles of ethanol is 0.0811 moles

calculation

molarity = moles of solute/ Kg of the solvent

where;

ethanol is the solute while water is the solvent

Molarity = 0.950 M

moles of the solute = ? moles

Kg of the solvent = 85.4 /1000 =0.0854 Kg

make moles of solute the subject of the formula by multiplying both side of the formula by Kg of the solvent

moles of solute = molarity x Kg of the solvent

= 0.950 x 0.0854 = 0.0811 moles