Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 150 ml of a 74 % (w/v) solution to prepare 16 % w/v solution? |
| 2 | If 430 ml of a 55 % v/v solution is diluted to 2600 ml , what is the percent strength of the diluted solution? |
| 3 | If 910 ml of a 1 : 78 (w/v) solution is diluted to 1000 ml, what is the ratio strength of the new solution? |
| 4 | If 8 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 43 % elixir can be prepared from 30 ml of a 88 % elixir? |
| 6 | If a cough syrup contains 20 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 250 ml of 35 % alcohol, 100 ml of 65 % alcohol, and 190 ml of 10 % alcohol? |
| 8 | A pharmacist combines 9 pints of a 5 % w/v povidone-iodine solution with 5 quarts of 10 % w/v povidone-iodine solution. What is the strength of the resulting solution? |
| 9 |
How many milliliters of 3 % and a 15 % solution do you need to prepare 3 gallon of 8 % solution? |
| 10 |
What proportion of 15 % zinc oxide and 90 % zinc oxide do you need to make 75 % zinc oxide? |
| 11 |
How many grams of 3 % hydrocortisone cream be mixed with 480 g of 0.5 % hydrocortisone cream to make a 1.50 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 3.50 L of 1: 900 w/v solution to make a 1: 7700 w/v solution? |
| 13 |
How many grams of a 8.50 % 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
11 % 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 780 ml of 44 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 900 ml of water, 900 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 1.60 should be mixed with 6000 mL of a syrup having a specific gravity of 1.16 to obtain a product having a specific gravity of 1.57? |
Answers
The Answer to question 1 is: 543.75 ml
The Answer to question 2 is: 9.10 % v/v
The Answer to question 3 is: 1 : 86
The Answer to question 4 is: 0.25 %
The Answer to question 5 is: 61.40 ml
The Answer to question 6 is: 360.00 mg
The Answer to question 7 is: 32 % v/v
The Answer to question 8 is: 7.63 % w/v
The Answer to question 9 is: 4731.25 ml of 15 % , 6623.75 ml of 3 %
The Answer to question 10 is: 1 : 4
The Answer to question 11 is: 320.00 grams
The Answer to question 12 is: 26444.40 ml
The Answer to question 13 is: 801.18 grams
The Answer to question 14 is: 24.53 ml
The Answer to question 15 is: 333.69 ml
The Answer to question 16 is: 1.01
The Answer to question 17 is: 82000.00 ml