Concentration and Dilution Practice Problems

How many mL of stock solution of 2M NaCl do you need to prepare 100 mL of 0.150M NaCl?

• 7.5 mL

• 15 mL

• 1333 mL

• 200 mL

How many mL of 1.0M KBr solution would you need to prepare 250 mL of a 0.2M dilution?

• 175 mL

• 250 mL

• 50 mL

• 5 mL

What would the molarity of a solution be if you took 10 mL of a 13M stock solution and made a 300 mL solution?

• 390M

• 230M

• 0.43M

• 0.26M

You are adding a chlorine solution to a swimming pool. The stock solution of chlorine is 1000M. Your swimming pool (75,000 L) needs to be at a concentration of 0.1M. How much of the stock solution should you add?

• 7500 L

• .75 L

• 750 L

• 7.5 L

What is the molarity of a solution made by diluting 26.5 mL of 6.00M HNO₃ to a volume of 250 mL?

• 15.9 M
• 0.636 M
• 0.642 M
• 1.59 M

What would you do to make a solution more concentrated?

• add more solvent

• add more solute

• add more solvent and solute

• pour some of the solution out

Which action would NOT change the concentration of a solution at all?

• adding more solvent

• pouring out some of the solution

• evaporating some of the solute

• removing some solvent

To make a Kool-Aid solution less concentrated, which would you do?

• add more solute

• add more solvent

• pour out some of the Kool-Aid

• add more solvent AND solute

If you make a solution of Kool-Aid and it is too concentrated, what would be true about its taste?

• it would be too watery

• it would taste just right

• it would taste too sugary

• it would be too salty

What could you do to increase the concentration of a solution?

• pour out some of the solution

• add more solvent

• pour it into a larger container

• add more solute