Weigh out 7.3 g of the dried potassium hydrogen phthalate (MW:204.22 g/mol) and prepare 250 ml solution by dissolving in deionized water. Calculate the molar concentration of the

Question

Weigh out 7.3 g of the dried potassium hydrogen

phthalate (MW:204.22 g/mol) and prepare 250 ml

solution by dissolving in deionized water. Calculate the

molar concentration of the potassium hydrogen phthalate

solution

Answer 1

Molar concentration (M) = moles solute/liter of solution

moles of solute = 7.3 g x 1 mol / 204.22 g = 0.0357 moles

liters of solution = 250 ml x 1 L/1000 ml = 0.250 L

Molar concentration (M) = 0.0357 moles / 0.250 L = 0.1428 M = 0.14 M (2 sig. figs.)