C1V1 practice problems 1. If you need to make 375 mL of 1.25 M NaCl from a 5 M NaCl stock, what volume of 5 M NaCl do you need? 2. Your student helper has made up a stock of 5% glycerol by taking 110 mL of 60% glycerol and bringing the solution to a final volume of 1L. Did she make this solution correctly? 3. You are in charge of solutions for a teaching lab. You know that tomorrow’s experiment requires that each student will use 250 mL of 1X TBE to run a gel. There are twenty-five students in your class. You make the 1X TBE from a 10X stock. When you check your reagents, you see that you have 150 mL of 10X TBE remaining. Do you need to make up more 10X stock? 4. Your experimental protocol directed you to add 13 mL of 3 M KCl to a graduated cylinder, and bring to a final volume of 1 L to make a dilute KCl solution. When you are checking your notes, you realize that you added 15 mL of 3 M KCl. There is not enough 3 M KCl to start over, so how can you fix your mistake?