Calculate the molality of acetone in an aqueous solution with a mole fraction for acetone of 0.235. Answer in units of m.

To calculate the molality of a solute in a solution, we need the following information:

1. Moles of solute: This represents the amount of solute present in the solution. We can calculate the moles of solute using the mole fraction.

2. Mass of solvent: This represents the mass of the solvent present in the solution.

Molality (m) is defined as the moles of solute divided by the mass of the solvent in kilograms. The formula for calculating molality is:

m = (moles of solute) / (mass of solvent in kg)

In this case, the mole fraction of acetone is given as 0.235. The mole fraction is defined as the ratio of moles of solute to the total moles of all components in the solution. Therefore, we can assume that the mole fraction of the solvent (water) is 1 - mole fraction of acetone.

Since we do not have the actual quantities of the solution, we will assume a convenient value of 1 kilogram for the solvent (water). This means the mass of the solvent is 1 kg.

Now, we can calculate the moles of acetone:

moles of acetone = mole fraction of acetone * moles of all components

In this case, moles of all components = moles of acetone + moles of water. Since we have 1 mole of acetone and 1 mole of water, we can write the equation as:

1 = 0.235 * (moles of acetone + 1)

Simplifying the equation:

1 = 0.235 * moles of acetone + 0.235

0.765 = 0.235 * moles of acetone

moles of acetone = 0.765 / 0.235

moles of acetone = 3.26

Finally, we can use the mole value of acetone and the mass of the solvent to calculate the molality:

m = (moles of acetone) / (mass of solvent in kg)

m = 3.26 / 1

m = 3.26 m

Therefore, the molality of acetone in the aqueous solution is 3.26 m.

acetone = Ac2O

I would try something like this.
Take some value of g H2O, say 18 g (you may need to use more precise numbers than I).
moles H2O = 18/18 = 1 mole.
Then XH2O = 0.765 = (1 mole H2O/1 mole H2O + x moles Ac2O).
Solve for x moles Ac2O. Convert mols Ac2O to grams Ac2O remembering g = mols x molar mass.

Now you have grams water and mole Ac2O, molality = moles/kg solvent.
Post your work if you get stuck.