Calculate the mole fraction of phosphoric acid (H₃PO₄)in a 29.1% (by mass)aqueous solution. A)0.0702 B)0.0755 C)0.140 D)0.0351 E)The density of the solution is needed to solve the problem.

Question

Quizplus · Accepted Answer

To calculate the mole fraction of phosphoric acid, we need to know the molarity of the solution. However, we are only given the percent by mass (mass of solute/mass of solution).

Assuming we have 100 g of the solution, we have 29.1 g of phosphoric acid and 70.9 g of water.

To convert the mass of phosphoric acid to moles, we need to divide by its molar mass:

29.1 g / 98.0 g/mol = 0.297 mol

To convert the mass of water to moles, we need to divide by its molar mass:

70.9 g / 18.0 g/mol = 3.94 mol

The total moles of solute and solvent are:

moles of solute = 0.297 
moles of solvent = 3.94

The mole fraction of the solute is:

mol fraction = moles of solute / (moles of solute + moles of solvent) = 0.297 / (0.297 + 3.94) = 0.0702

Therefore, the answer is A) 0.0702.

Calculate the Mole Fraction of Phosphoric Acid (H3PO4)in a 29

Calculate the Mole Fraction of Phosphoric Acid (H₃PO₄)in a 29