Calculate the mole fraction of HCl in a 7.20% (by mass)aqueous solution.
A)0.0369
B)0.0383
C)0.0739
D)0.0185
E)The density of the solution is needed to solve the problem.

Question

Quizplus · Accepted Answer

The mole fraction of HCl can be calculated using the formula:Mole fraction of HCl = (moles of HCl) / (total moles of solution)To calculate the moles of HCl, we need to know the mass of HCl in the solution. We can calculate this using the mass percentage:Mass of HCl = (mass percentage of HCl) * (mass of solution)Mass of HCl = (7.20%) * (100 g) = 7.20 gTo convert the mass of HCl to moles, we need to divide by the molar mass of HCl:Moles of HCl = (mass of HCl) / (molar mass of HCl)Moles of HCl = (7.20 g) / (36.46 g/mol) = 0.198 molTo calculate the total moles of solution, we need to know the mass of the solution. We can assume that the density of the solution is 1 g/mL, so the mass of the solution is equal to the volume of the solution:Mass of solution = (volume of solution) * (density of solution)Mass of solution = (100 mL) * (1 g/mL) = 100 gTo convert the mass of the solution to moles, we need to divide by the molar mass of water:Total moles of solution = (mass of solution) / (molar mass of water)Total moles of solution = (100 g) / (18.02 g/mol) = 5.55 molNow we can calculate the mole fraction of HCl:Mole fraction of HCl = (moles of HCl) / (total moles of solution)Mole fraction of HCl = (0.198 mol) / (5.55 mol) = 0.0369Therefore, the mole fraction of HCl in the solution is 0.0369.

Calculate the Mole Fraction of HCl in a 7