# Question #2b0e3

##### 1 Answer

The molarity of a solution is the number of moles of solute per liter of solution.

For example, a 0.10 M HCl solution (read as "point one molar") contains 0.10 mole of HCl in every liter of solution. Anytime you see the abbreviation M, you should think of it as mol/L.

**Problem 1.** What is the molarity of a solution that contains 1.724 moles of

Calculation:

The container for this solution would be labeled

**Problem 2.** 70.0 grams of glucose (

First determine the molar mass of glucose, which is 180.1559 g/mol. Next, divide the given mass by the molar mass to get moles.

Calculation:

Now determine the molarity of the glucose solution.

Calculation:

The container for this solution would be labeled

**Problem 3.** What is the molarity of a solution prepared by dissolving 15.0 g of sodium hydroxide (NaOH) in enough water to make a total of 225 mL of solution?

First determine the number of moles in 15.0 g of NaOH by dividing the given mass by the molar mass for NaOH, which is 39.997 g/mol.

Calculation:

The volume has been given in mL. You need to convert 225 mL to liters.

Calculation:

Now determine the molarity.

Calculation:

The container for this solution would be labeled "1.67 M NaOH".We would say that this is a 1.67 molar solution of NaOH or sodium hydroxide.

The following diagram can help you remember how to calculate moles from given mass and molar mass, and how to calculate molarity from moles and volume in liters.

Here is a video which discusses how to complete a calculation of molarity.

video from: Noel Pauller