What is the molarity (M) of a solution prepared by placing 10 g of NaOH (MW = 40) in a flask and diluting to 500 mL?

Question

Quizplus · Accepted Answer

The solution prepared in the problem has a concentration of 10 g/500 mL.The definition of a molar (M) solution is the number of moles of solute per liter of solution, mol/L.This problem requires converting g/mL to mol/L.For the numerator, the molecular weight is used to convert 10 g to 0.25 mol.At this point, 10 g/500 mL is equal to 0.25 mol/500 mL.These units do not, however, meet the definition of the units for a molar solution.For the denominator, the desired unit is L (which is equal to 1000 mL).To make this conversion, multiply the numerator and the denominator by 2.This gives 0.5 mol/1000 mL which equals 0.5 mol/L, the proper units for molarity.This solution is a 0.5 M solution.

What Is the Molarity (M) of a Solution Prepared by Placing