Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 260 ml of a 74 % (w/v) solution to prepare 13 % w/v solution? |
| 2 | If 775 ml of a 90 % v/v solution is diluted to 2700 ml , what is the percent strength of the diluted solution? |
| 3 | If 895 ml of a 1 : 68 (w/v) solution is diluted to 2300 ml, what is the ratio strength of the new solution? |
| 4 | If 13 ml of a 0.70 % nasal spray was diluted with 6 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 48 % elixir can be prepared from 40 ml of a 80 % elixir? |
| 6 | If a cough syrup contains 42 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 300 ml of 45 % alcohol, 125 ml of 50 % alcohol, and 200 ml of 25 % 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 4 % and a 13 % solution do you need to prepare 2 gallon of 11 % solution? |
| 10 |
What proportion of 20 % zinc oxide and 80 % zinc oxide do you need to make 75 % 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 1.00 L of 1: 2400 w/v solution to make a 1: 8100 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
26 % 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 160 ml of 64 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 500 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 1.45 should be mixed with 1500 mL of a syrup having a specific gravity of 1.14 to obtain a product having a specific gravity of 1.16? |
Answers
The Answer to question 1 is: 1220.00 ml
The Answer to question 2 is: 25.83 % v/v
The Answer to question 3 is: 1 : 175
The Answer to question 4 is: 0.48 %
The Answer to question 5 is: 66.67 ml
The Answer to question 6 is: 36.00 mg
The Answer to question 7 is: 40 % v/v
The Answer to question 8 is: 7.63 % w/v
The Answer to question 9 is: 5887.78 ml of 13 % , 1682.22 ml of 4 %
The Answer to question 10 is: 1 : 11
The Answer to question 11 is: 95.00 grams
The Answer to question 12 is: 2375.00 ml
The Answer to question 13 is: 2724.00 grams
The Answer to question 14 is: 29.72 ml
The Answer to question 15 is: 99.56 ml
The Answer to question 16 is: 1.02
The Answer to question 17 is: 103.45 ml