Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 110 ml of a 76 % (w/v) solution to prepare 13 % w/v solution? |
| 2 | If 265 ml of a 20 % v/v solution is diluted to 1700 ml , what is the percent strength of the diluted solution? |
| 3 | If 965 ml of a 1 : 100 (w/v) solution is diluted to 2500 ml, what is the ratio strength of the new solution? |
| 4 | If 45 ml of a 5.00 % nasal spray was diluted with 4 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 26 % elixir can be prepared from 75 ml of a 65 % elixir? |
| 6 | If a cough syrup contains 36 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 450 ml of 30 % alcohol, 100 ml of 55 % alcohol, and 280 ml of 25 % alcohol? |
| 8 | A pharmacist combines 7 pints of a 5 % w/v povidone-iodine solution with 8 quarts of 10 % w/v povidone-iodine solution. What is the strength of the resulting solution? |
| 9 |
How many milliliters of 5 % and a 16 % solution do you need to prepare 3 gallon of 12 % solution? |
| 10 |
What proportion of 20 % zinc oxide and 75 % zinc oxide do you need to make 65 % zinc oxide? |
| 11 |
How many grams of 2 % hydrocortisone cream be mixed with 440 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: 400 w/v solution to make a 1: 9700 w/v solution? |
| 13 |
How many grams of a 2.50 % w/w benzocaine ointment can be prepared by diluting 1 lb of a 25 % 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 640 ml of 52 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 400 ml of water, 1250 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 1.58 should be mixed with 1000 mL of a syrup having a specific gravity of 1.12 to obtain a product having a specific gravity of 1.43? |
Answers
The Answer to question 1 is: 533.08 ml
The Answer to question 2 is: 3.12 % v/v
The Answer to question 3 is: 1 : 259
The Answer to question 4 is: 4.59 %
The Answer to question 5 is: 187.50 ml
The Answer to question 6 is: 108.00 mg
The Answer to question 7 is: 31 % v/v
The Answer to question 8 is: 8.48 % w/v
The Answer to question 9 is: 7225.91 ml of 16 % , 4129.09 ml of 5 %
The Answer to question 10 is: 2 : 9
The Answer to question 11 is: 220.00 grams
The Answer to question 12 is: 52312.50 ml
The Answer to question 13 is: 4540.00 grams
The Answer to question 14 is: 67.70 ml
The Answer to question 15 is: 323.58 ml
The Answer to question 16 is: 1.02
The Answer to question 17 is: 2066.67 ml