Molarity Calculations

Front

What is molarity?

Back

Molarity (M) is a measure of concentration defined as the number of moles of solute per liter of solution.

Front

How do you calculate molarity?

Back

Molarity = moles of solute / liters of solution.

Front

What is the molarity of a solution containing 180 g of NaCl in 1.0 L of solution?

Back

Molarity = (180 g / 58.44 g/mol) / 1.0 L = 3.09 M.

Front

If you have 2 moles of solute in 4 L of solution, what is the molarity?

Back

Molarity = 2 moles / 4 L = 0.5 M.

Front

What is the molarity of a solution made by dissolving 10 g of KCl in 500 mL of water?

Back

Molarity = (10 g / 74.55 g/mol) / 0.5 L = 0.268 M.

Front

Calculate the molarity of a solution with 5 moles of solute in 2.5 L of solution.

Back

Molarity = 5 moles / 2.5 L = 2 M.

Front

What is the final concentration of a solution made by dissolving 20 g of NaOH in 1 L of water?

Back

Molarity = (20 g / 40 g/mol) / 1 L = 0.5 M.

Front

How many moles are in 250 mL of a 0.2 M solution?

Back

Moles = Molarity x Volume = 0.2 M x 0.25 L = 0.05 moles.

Front

What is the molarity of a solution containing 0.5 moles of solute in 1.5 L of solution?

Back

Molarity = 0.5 moles / 1.5 L = 0.333 M.

Front

If you dilute a 2 M solution to 4 L, what is the new molarity if you add 2 L of water?

Back

Molarity = (2 M x 2 L) / 4 L = 1 M.