What is the definition of molarity?

Calculate the molarity of a solution containing 2 moles of solute in 4 liters of solution.

If you have a 3.0 M solution and you need 9.0 moles of solute, how many liters of solution do you need?

How many grams of NaCl are in 0.5000 liters of a 2.000 M NaCl solution? (Molar mass of NaCl = 58.44 g/mol)

You need to prepare 250. mL of a 0.100 M HCl solution from a 1.00 M stock solution. How much of the stock solution and water will you use?