What is the molarity of a solution of KCl if 1500. mL contains 149.2 grams of KCl? (Atomic mass of K = 39.10 g/mol and Cl = 35.45 g/mol)

The molarity of a solution of KCl is 1.33

Explanation:

The Molarity (M) or Molar Concentration is the number of moles of solute that are dissolved in a given volume. In other words, the molarity is the number of moles of solute per liter of solution.

Molarity is determined by the expression:

Molarity is expressed in units ().

So in this case you need to know the number of moles. For that you must know the molar mass of KCl. You know:

So the molar mass of KCl is: KCl= 39.10 g/mol + 35.45 g/mol=  74.55 g/mol

Then the following rule of three applies: if 74.55 grams of KCl are in 1 mole, 149.2 grams of KCl in how many moles will they be?

moles= 2

So you know:

Replacing in the definition of molarity:

Solving:

Molarity= 1.33

The molarity of a solution of KCl is 1.33