Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 130 ml of a 58 % (w/v) solution to prepare 19 % w/v solution? |
| 2 | If 985 ml of a 45 % v/v solution is diluted to 1100 ml , what is the percent strength of the diluted solution? |
| 3 | If 510 ml of a 1 : 296 (w/v) solution is diluted to 1500 ml, what is the ratio strength of the new solution? |
| 4 | If 29 ml of a 8.00 % nasal spray was diluted with 22 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 20 % elixir can be prepared from 55 ml of a 36 % elixir? |
| 6 | If a cough syrup contains 41 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 10 mg/ml? |
| 7 | What is the percentage strength (v/v) of an alcohol mixture that has a mix of 200 ml of 30 % alcohol, 125 ml of 65 % alcohol, and 230 ml of 15 % alcohol? |
| 8 | A pharmacist combines 7 pints of a 5 % w/v povidone-iodine solution with 1 quarts of 10 % w/v povidone-iodine solution. What is the strength of the resulting solution? |
| 9 |
How many milliliters of 1 % and a 14 % solution do you need to prepare 1 gallon of 8 % solution? |
| 10 |
What proportion of 15 % zinc oxide and 70 % zinc oxide do you need to make 40 % zinc oxide? |
| 11 |
How many grams of 5 % hydrocortisone cream be mixed with 300 g of 0.25 % hydrocortisone cream to make a 2.00 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 1.00 L of 1: 3600 w/v solution to make a 1: 5800 w/v solution? |
| 13 |
How many grams of a 3.50 % w/w benzocaine ointment can be prepared by diluting 1 lb of a 15 % w/w benzocaine ointment with white petrolatum? |
| 14 |
How many milliliters of a
17 % 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 490 ml of 42 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 900 ml of water, 600 ml of glycerin having a specific gravity of 1.25, and 1000 ml of alcohol having a specific gravity of 0.81? |
| 17 |
How many milliliters of a syrup having a specific gravity of 1.58 should be mixed with 4500 mL of a syrup having a specific gravity of 1.28 to obtain a product having a specific gravity of 1.38? |
Answers
The Answer to question 1 is: 266.84 ml
The Answer to question 2 is: 40.30 % v/v
The Answer to question 3 is: 1 : 871
The Answer to question 4 is: 4.55 %
The Answer to question 5 is: 99.00 ml
The Answer to question 6 is: 108.00 mg
The Answer to question 7 is: 32 % v/v
The Answer to question 8 is: 6.11 % w/v
The Answer to question 9 is: 2038.08 ml of 14 % , 1746.92 ml of 1 %
The Answer to question 10 is: 6 : 5
The Answer to question 11 is: 175.00 grams
The Answer to question 12 is: 611.10 ml
The Answer to question 13 is: 1945.71 grams
The Answer to question 14 is: 26.32 ml
The Answer to question 15 is: 200.10 ml
The Answer to question 16 is: 0.98
The Answer to question 17 is: 2250.00 ml