1. You have a bottle of NaCl (f.w. 58) in front of you. How much should you weigh out to make 100 mL of a 1% aqueous solution?

     

  2. You have a bottle of NaCl (f.w. 58) in front of you. How much should you weigh out to make 1.0 liter that is 1.0 M?

     

  3. You have a flast of 2% NaCl (f.w. 58) in front of you. How much of it should you use to make 100 mL that is 1%?

     

  4. You have a bottle of NaCl (f.w. 58) in front of you. How much should you weigh out to make 200 mL that is 1.5%?

     

  5. You have a bottle of NaCl (f.w. 58) in front of you. How much should you weigh out to make a liter that is 0.5 M?

     

  6. You have a flask of 10% sucrose (mol.wt. 348) in front of you. How much should you use to make 100 mL that is 1%?

     

  7. You have the bottle in front of you, which contains powdered MacConkey agar. You want to test whether your strain of E.coli is capable of using the sugar lactose. If the colonies that grow up are red, it uses lactose, but if they grow up light pink, they do not use lactose. How much of the MacConkey powder do you add to water to make 100 mL that 1%?

     

    How much to make 300 mL that is 0.5%?

     

  8. You are making stabs (or "deeps") for long-term storage of your cultures. While ordinary nutrient agar works fairly well, it would be better to use a nutrient agar that has only 1% agar - a bit slushy. So you find a bottle of nutrient broth, and make up 300 mL as per its label. How much pure agar powder do you weigh out to make that 300 mL to 1% in agar?

     

  9. You are microscopically comparing the erythrocytes of yourself with those from a person with sickle-cell anemia. You find your stock of normal saline (aka physiological saline) is depleted. How much NaCl do you add to 1000 mL of water to make it 0.9%?