Question

A solution is 0.0440 m LiF. What is the molarity of the solution if the density is 1.10 g/mL?

Answer 1

let the mass of solvent be 1000 g

now

we know that

molality = moles of LiF x 1000 / mass of solvent (g)

so

0.044 = moles of LiF x 1000 / 1000

moles of LiF = 0.044

now

we know that

mass = moles x molar mass

so

mass of LiF = 0.044 x 26

mass of LiF = 1.144

now

total mass of solution = 1000 + 1.144

mass of solution = 1001.144

now

we know that

volume = mass / density

so

volume of solution = 1001.144 / 1.1

volume of solution = 910.131 ml

now

we know that

molarity = moles of LiF x 1000 / volume of solution (ml)

so

molarity = 0.044 x 1000 / 910.131

molarity = 0.0483447

so

the molarity of the solution is 0.0483447 M