Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 140 ml of a 88 % (w/v) solution to prepare 26 % w/v solution? |
| 2 | If 460 ml of a 55 % v/v solution is diluted to 1400 ml , what is the percent strength of the diluted solution? |
| 3 | If 840 ml of a 1 : 238 (w/v) solution is diluted to 2400 ml, what is the ratio strength of the new solution? |
| 4 | If 36 ml of a 0.70 % nasal spray was diluted with 14 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 13 % elixir can be prepared from 45 ml of a 89 % elixir? |
| 6 | If a cough syrup contains 44 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 200 ml of 35 % alcohol, 250 ml of 75 % alcohol, and 300 ml of 15 % alcohol? |
| 8 | A pharmacist combines 8 pints of a 5 % w/v povidone-iodine solution with 4 quarts of 10 % w/v povidone-iodine solution. What is the strength of the resulting solution? |
| 9 |
How many milliliters of 2 % and a 9 % solution do you need to prepare 1 gallon of 4 % solution? |
| 10 |
What proportion of 20 % zinc oxide and 90 % zinc oxide do you need to make 30 % zinc oxide? |
| 11 |
How many grams of 2 % hydrocortisone cream be mixed with 440 g of 0.1 % hydrocortisone cream to make a 1.00 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 1.50 L of 1: 500 w/v solution to make a 1: 9900 w/v solution? |
| 13 |
How many grams of a 3.50 % w/w benzocaine ointment can be prepared by diluting 1 lb of a 35 % w/w benzocaine ointment with white petrolatum? |
| 14 |
How many milliliters of a
14 % 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 220 ml of 34 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 500 ml of water, 800 ml of glycerin having a specific gravity of 1.25, and 1400 ml of alcohol having a specific gravity of 0.81? |
| 17 |
How many milliliters of a syrup having a specific gravity of 1.54 should be mixed with 1000 mL of a syrup having a specific gravity of 1.09 to obtain a product having a specific gravity of 1.38? |
Answers
The Answer to question 1 is: 333.85 ml
The Answer to question 2 is: 18.07 % v/v
The Answer to question 3 is: 1 : 680
The Answer to question 4 is: 0.50 %
The Answer to question 5 is: 308.08 ml
The Answer to question 6 is: 12.00 mg
The Answer to question 7 is: 40 % v/v
The Answer to question 8 is: 7.50 % w/v
The Answer to question 9 is: 1081.43 ml of 9 % , 2703.57 ml of 2 %
The Answer to question 10 is: 6 : 1
The Answer to question 11 is: 396.00 grams
The Answer to question 12 is: 28200.00 ml
The Answer to question 13 is: 4540.00 grams
The Answer to question 14 is: 30.27 ml
The Answer to question 15 is: 72.73 ml
The Answer to question 16 is: 0.98
The Answer to question 17 is: 1812.50 ml