Molarity and Dilution 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 the number of moles from molarity and volume?

Back

Number of moles = Molarity (M) × Volume (L).

Front

What is the formula for dilution?

Back

C1V1 = C2V2, where C1 and V1 are the concentration and volume of the stock solution, and C2 and V2 are the concentration and volume of the diluted solution.

Front

If you dilute a solution from 1.0 M to 0.5 M, what happens to the volume?

Back

The volume increases; dilution means adding more solvent.

Front

How many moles of solute are in 1 L of a 2 M solution?

Back

2 moles of solute.

Front

What is the molarity of a solution made by dissolving 0.5 moles of NaCl in 1 L of water?

Back

0.5 M.

Front

How do you prepare a 0.1 M solution from a 1 M stock solution?

Back

Use the dilution formula: C1V1 = C2V2. For example, take 10 mL of 1 M solution and dilute it to 100 mL.

Front

What is the molarity of a solution if 0.2 moles of solute are dissolved in 0.5 L of solution?

Back

0.4 M.

Front

How many mL of a 3 M solution are needed to obtain 0.6 moles of solute?

Back

200 mL (using V = n/C).

Front

What is the concentration of a solution if 5 grams of NaCl are dissolved in 250 mL of water? (Molar mass of NaCl = 58.44 g/mol)

Back

0.34 M.