What is the mole fraction of NaOH in an aqueous solution that contains 33.4% NaOH by mass?
To find the mole fraction of NaOH in the solution, we need to determine the number of moles of NaOH and the total number of moles of all components in the solution.
First, let's assume we have 100 g of the solution. Since the solution is 33.4% NaOH by mass, this means we have 33.4 g of NaOH and 66.6 g of water (or any other solvent).
Next, we need to convert the mass of NaOH to moles. To do this, we will use the molar mass of NaOH, which is approximately 40 g/mol.
Moles of NaOH = Mass of NaOH / Molar mass of NaOH
= 33.4 g / 40 g/mol
= 0.835 mol NaOH
Now, let's calculate the moles of water. To do this, we will use the molar mass of water, which is approximately 18 g/mol.
Moles of water = Mass of water / Molar mass of water
= 66.6 g / 18 g/mol
= 3.7 mol water
Finally, the mole fraction of NaOH is given by the moles of NaOH divided by the total moles of all components in the solution.
Mole fraction of NaOH = Moles of NaOH / (Moles of NaOH + Moles of water)
= 0.835 mol / (0.835 mol + 3.7 mol)
= 0.184
Therefore, the mole fraction of NaOH in the solution is approximately 0.184.