Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 230 ml of a 32 % (w/v) solution to prepare 9 % w/v solution? |
| 2 | If 605 ml of a 50 % v/v solution is diluted to 2200 ml , what is the percent strength of the diluted solution? |
| 3 | If 240 ml of a 1 : 336 (w/v) solution is diluted to 700 ml, what is the ratio strength of the new solution? |
| 4 | If 23 ml of a 3.00 % nasal spray was diluted with 12 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 25 % elixir can be prepared from 50 ml of a 56 % elixir? |
| 6 | If a cough syrup contains 21 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 5 mg/ml? |
| 7 | What is the percentage strength (v/v) of an alcohol mixture that has a mix of 400 ml of 30 % alcohol, 225 ml of 55 % alcohol, and 150 ml of 15 % alcohol? |
| 8 | A pharmacist combines 10 pints of a 5 % w/v povidone-iodine solution with 7 quarts of 10 % w/v povidone-iodine solution. What is the strength of the resulting solution? |
| 9 |
How many milliliters of 6 % and a 15 % solution do you need to prepare 2 gallon of 11 % solution? |
| 10 |
What proportion of 10 % zinc oxide and 85 % zinc oxide do you need to make 65 % zinc oxide? |
| 11 |
How many grams of 5 % hydrocortisone cream be mixed with 860 g of 0.25 % hydrocortisone cream to make a 4.00 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 2.25 L of 1: 1500 w/v solution to make a 1: 6700 w/v solution? |
| 13 |
How many grams of a 5.00 % w/w benzocaine ointment can be prepared by diluting 1 lb of a 30 % w/w benzocaine ointment with white petrolatum? |
| 14 |
How many milliliters of a
16 % 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 300 ml of 42 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 200 ml of water, 900 ml of glycerin having a specific gravity of 1.25, and 1300 ml of alcohol having a specific gravity of 0.81? |
| 17 |
How many milliliters of a syrup having a specific gravity of 1.47 should be mixed with 1000 mL of a syrup having a specific gravity of 1.27 to obtain a product having a specific gravity of 1.30? |
Answers
The Answer to question 1 is: 587.78 ml
The Answer to question 2 is: 13.75 % v/v
The Answer to question 3 is: 1 : 980
The Answer to question 4 is: 1.97 %
The Answer to question 5 is: 112.00 ml
The Answer to question 6 is: 48.00 mg
The Answer to question 7 is: 34 % v/v
The Answer to question 8 is: 7.92 % w/v
The Answer to question 9 is: 4205.56 ml of 15 % , 3364.44 ml of 6 %
The Answer to question 10 is: 4 : 11
The Answer to question 11 is: 3225.00 grams
The Answer to question 12 is: 7800.00 ml
The Answer to question 13 is: 2724.00 grams
The Answer to question 14 is: 65.48 ml
The Answer to question 15 is: 122.51 ml
The Answer to question 16 is: 0.99
The Answer to question 17 is: 176.47 ml