Question

What is the molality of a solution made by dissolving 50.00 g of glucose, C6H12O6, in 500.0 g water. Give your answer to 3 significant figures.

Answer 1

Answer:

m = 0.5556 mol/kg

Explanation:

The molality of any solution is calculated using the following expression:

m = moles solute / kg solvent (1)

So in order to calculate the molality of this solution, we need to calculate the moles of the glucose using the expression:

n = mass / molecular weight  (2)

The molecular weight of glucose, can be calculated using the molecular mass of the atoms in the glucose:

C = 12 g/mol; H = 1 g/mol; O = 16 g/mol

the molecular weight is:

MW = (12*6) + (12*1) + (6*16) = 180 g/mol

Then, the moles of glucose:

moles = 50 / 180 = 0.2778 moles

The solvent in this case is water, and 500 g of water is 0.5 kg of water, so the molality is:

m = 0.2778 / 0.5

m = 0.5556 mol/kg