Calculate the molality of ethanol in a solution of water, if the mole fraction of ethanol is
0.300.
How do I even start? Please help me!
Let's suppose we start with 1 mole of material. That means we will have 0.3 mole ethanol and 0.7 mole of water.
Now convert 0.7 mole water to kg.
That will be 0.7 mole x (18.015 g/mole) x (1 kg/1000 g) = ?? kg solvent (water).
molality = m = moles ethanol/kg solvent.
You know moles ethanol = 0.3 and you have kg water above. Done.
Oh, okay. Thank you so much!
that is incorrect. the actual answer is 34.6 m
34.3
Answers question?
To calculate the molality of ethanol in a solution of water, you need to know the mole fraction of ethanol.
Mole fraction is the ratio of the number of moles of a particular component to the total number of moles of all components in the solution.
Given that the mole fraction of ethanol is 0.300, we can assume that the total number of moles of all components in the solution is 1.00 (since mole fractions always add up to 1).
Now, to find the mole fraction of ethanol, we can use the formula:
Mole fraction of ethanol = Moles of ethanol / Total moles in solution
0.300 = Moles of ethanol / 1.00
Rearranging the formula, we get:
Moles of ethanol = 0.300 * 1.00
Moles of ethanol = 0.300
So, the moles of ethanol in the solution is 0.300.
Now, to find the molality of ethanol, you need to know the mass of the solvent (water) in kilograms. Let's assume that the mass of water is 1000 grams (1 kilogram).
Molality is defined as the number of moles of solute per kilogram of solvent. Using this definition, we can calculate the molality:
Molality = Moles of ethanol / Mass of water (in kg)
Molality = 0.300 / 1.00
Molality = 0.300 mol/kg
Therefore, the molality of ethanol in the solution is 0.300 mol/kg.