Can somebody please help with questions 1 through 7 Dont for

Can somebody please help with questions 1 through 7?

Don\'t forget si units.

1. You are testing an antibiotic which is a solid in pure form. You have a 2% solution. If you inject 5 ml into a volunteer, how many grams did you inject?

2. You need to make more of your 2% antibiotic solution. You have 1 gram; how much sterile water do you add to make a 2% solution, using all of the antibiotic?

3. You plan a big study of the antibiotic for which you will need 500 ml of the 2% solution. How many grams will you need to buy (minimum)?

4.You have a 20% glucose stock solution for making media to grow your experimental bacteria. If you are making 1 L (1000 ml) of medium and add 50 ml of your stock solution, what will the final concentration be?

5. You are preparing a reaction mixture to test a reaction that requires copper ion. You need there to be 1 mM copper chloride in the reaction mix, and you need 10 ml of mix. Your stock solution is 100 mM. How much do you need to add to your mix?

6. Your assistant goofed up and made 50 ml of a 10% stock solution of the drug you are studying. It was supposed to be 5%. If you add water to dilute it to the correct concentration, how much total stock solution will you now have? How much water did you add to get that?

7. You are measuring protein produced by your bacteria. You take 2 ml of the protein solution and add water to make 5 ml. You now measure the concentration of the protein and find it to be 2 mg/ml. What was the original concentration?

Solution

1. You are testing an antibiotic which is a solid in pure form. You have a 2% solution. If you inject 5 ml into a volunteer, how many grams did you inject?

Ans: 2% solution is prepared by mixing 2 gms of antibiotic in 100 ml of solution. Hence, 5 ml contains 0.1 gm (100 mg).

2. You need to make more of your 2% antibiotic solution. You have 1 gram; how much sterile water do you add to make a 2% solution, using the entire antibiotic?

Ans: 2% solution is prepared by mixing 2 gms of antibiotic in 100 ml of solution. Hence, you need 50 ml of sterile to dissolve 1 gm of antibiotic powder to get 2% antibiotic solution.

3. You plan a big study of the antibiotic for which you will need 500 ml of the 2% solution. How many grams will you need to buy (minimum)?

Ans: You need minimum of 10 gms of antibiotic powder to get 500 ml of the 2% solution.

4. You have a 20% glucose stock solution for making media to grow your experimental bacteria. If you are making 1 L (1000 ml) of medium and add 50 ml of your stock solution, what will the final concentration be?

Ans: You can use C1V1=C2V2 formula,

Concentration_(start) x Volume_(start) = Concentration_(final) x Volume_(final)

The final concentration of 1 L solution is 0.1%