Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 140 ml of a 38 % (w/v) solution to prepare 14 % w/v solution? |
| 2 | If 520 ml of a 30 % v/v solution is diluted to 900 ml , what is the percent strength of the diluted solution? |
| 3 | If 620 ml of a 1 : 60 (w/v) solution is diluted to 1900 ml, what is the ratio strength of the new solution? |
| 4 | If 44 ml of a 8.00 % nasal spray was diluted with 26 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 42 % elixir can be prepared from 90 ml of a 81 % elixir? |
| 6 | If a cough syrup contains 25 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 7 mg/ml? |
| 7 | What is the percentage strength (v/v) of an alcohol mixture that has a mix of 300 ml of 35 % alcohol, 275 ml of 75 % alcohol, and 260 ml of 15 % alcohol? |
| 8 | A pharmacist combines 8 pints of a 5 % w/v povidone-iodine solution with 3 quarts of 10 % w/v povidone-iodine solution. What is the strength of the resulting solution? |
| 9 |
How many milliliters of 7 % and a 19 % solution do you need to prepare 4 gallon of 15 % solution? |
| 10 |
What proportion of 5 % zinc oxide and 45 % zinc oxide do you need to make 10 % zinc oxide? |
| 11 |
How many grams of 3 % hydrocortisone cream be mixed with 380 g of 0.5 % hydrocortisone cream to make a 1.00 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 2.25 L of 1: 2200 w/v solution to make a 1: 9400 w/v solution? |
| 13 |
How many grams of a 5.50 % 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
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 170 ml of 76 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 200 ml of water, 1100 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 1.59 should be mixed with 4000 mL of a syrup having a specific gravity of 1.17 to obtain a product having a specific gravity of 1.40? |
Answers
The Answer to question 1 is: 240.00 ml
The Answer to question 2 is: 17.33 % v/v
The Answer to question 3 is: 1 : 184
The Answer to question 4 is: 5.03 %
The Answer to question 5 is: 173.57 ml
The Answer to question 6 is: 120.00 mg
The Answer to question 7 is: 42 % v/v
The Answer to question 8 is: 7.14 % w/v
The Answer to question 9 is: 10093.33 ml of 19 % , 5046.67 ml of 7 %
The Answer to question 10 is: 7 : 1
The Answer to question 11 is: 95.00 grams
The Answer to question 12 is: 7363.60 ml
The Answer to question 13 is: 1238.18 grams
The Answer to question 14 is: 53.57 ml
The Answer to question 15 is: 125.62 ml
The Answer to question 16 is: 1.03
The Answer to question 17 is: 4842.11 ml