Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 130 ml of a 46 % (w/v) solution to prepare 27 % w/v solution? |
| 2 | If 695 ml of a 65 % v/v solution is diluted to 2500 ml , what is the percent strength of the diluted solution? |
| 3 | If 760 ml of a 1 : 270 (w/v) solution is diluted to 2000 ml, what is the ratio strength of the new solution? |
| 4 | If 40 ml of a 0.90 % nasal spray was diluted with 18 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 26 % elixir can be prepared from 80 ml of a 47 % elixir? |
| 6 | If a cough syrup contains 35 mg of a drug in each teaspoonful, how many mg of drug needs to be added to a 60 ml container of the syrup to make the concentration 9 mg/ml? |
| 7 | What is the percentage strength (v/v) of an alcohol mixture that has a mix of 250 ml of 45 % alcohol, 275 ml of 65 % alcohol, and 110 ml of 15 % alcohol? |
| 8 | A pharmacist combines 8 pints of a 5 % w/v povidone-iodine solution with 10 quarts of 10 % w/v povidone-iodine solution. What is the strength of the resulting solution? |
| 9 |
How many milliliters of 5 % and a 13 % solution do you need to prepare 4 gallon of 7 % solution? |
| 10 |
What proportion of 25 % zinc oxide and 90 % zinc oxide do you need to make 65 % zinc oxide? |
| 11 |
How many grams of 4 % hydrocortisone cream be mixed with 740 g of 0.25 % hydrocortisone cream to make a 3.50 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 1.25 L of 1: 600 w/v solution to make a 1: 5800 w/v solution? |
| 13 |
How many grams of a 7.00 % w/w benzocaine ointment can be prepared by diluting 1 lb of a 25 % w/w benzocaine ointment with white petrolatum? |
| 14 |
How many milliliters of a
28 % w/v stock solution benzalkonium chloride
should be used in preparing the following prescription? |
| 15 |
How many milliliters of 85 % (w/w) lactic acid with a specific gravity of 1.21 be used to prepare 130 ml of 68 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 200 ml of water, 750 ml of glycerin having a specific gravity of 1.25, and 1100 ml of alcohol having a specific gravity of 0.81? |
| 17 |
How many milliliters of a syrup having a specific gravity of 1.49 should be mixed with 5000 mL of a syrup having a specific gravity of 1.13 to obtain a product having a specific gravity of 1.27? |
Answers
The Answer to question 1 is: 91.48 ml
The Answer to question 2 is: 18.07 % v/v
The Answer to question 3 is: 1 : 711
The Answer to question 4 is: 0.62 %
The Answer to question 5 is: 144.62 ml
The Answer to question 6 is: 120.00 mg
The Answer to question 7 is: 48 % v/v
The Answer to question 8 is: 8.57 % w/v
The Answer to question 9 is: 3785.00 ml of 13 % , 11355.00 ml of 5 %
The Answer to question 10 is: 5 : 8
The Answer to question 11 is: 4810.00 grams
The Answer to question 12 is: 10833.30 ml
The Answer to question 13 is: 1621.43 grams
The Answer to question 14 is: 29.62 ml
The Answer to question 15 is: 85.95 ml
The Answer to question 16 is: 0.99
The Answer to question 17 is: 3181.82 ml