Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 210 ml of a 86 % (w/v) solution to prepare 4 % w/v solution? |
| 2 | If 400 ml of a 55 % v/v solution is diluted to 900 ml , what is the percent strength of the diluted solution? |
| 3 | If 850 ml of a 1 : 286 (w/v) solution is diluted to 1400 ml, what is the ratio strength of the new solution? |
| 4 | If 34 ml of a 10.00 % nasal spray was diluted with 2 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 33 % elixir can be prepared from 20 ml of a 65 % elixir? |
| 6 | If a cough syrup contains 17 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 350 ml of 45 % alcohol, 100 ml of 75 % alcohol, and 150 ml of 10 % alcohol? |
| 8 | A pharmacist combines 1 pints of a 5 % w/v povidone-iodine solution with 4 quarts of 10 % w/v povidone-iodine solution. What is the strength of the resulting solution? |
| 9 |
How many milliliters of 3 % and a 14 % solution do you need to prepare 2 gallon of 12 % solution? |
| 10 |
What proportion of 20 % zinc oxide and 50 % zinc oxide do you need to make 35 % zinc oxide? |
| 11 |
How many grams of 3 % hydrocortisone cream be mixed with 780 g of 0.25 % hydrocortisone cream to make a 0.50 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 2.25 L of 1: 3300 w/v solution to make a 1: 5100 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
20 % 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 110 ml of 64 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 400 ml of water, 950 ml of glycerin having a specific gravity of 1.25, and 1400 ml of alcohol having a specific gravity of 0.81? |
| 17 |
How many milliliters of a syrup having a specific gravity of 1.55 should be mixed with 2500 mL of a syrup having a specific gravity of 1.11 to obtain a product having a specific gravity of 1.13? |
Answers
The Answer to question 1 is: 4305.00 ml
The Answer to question 2 is: 24.44 % v/v
The Answer to question 3 is: 1 : 471
The Answer to question 4 is: 9.44 %
The Answer to question 5 is: 39.39 ml
The Answer to question 6 is: 216.00 mg
The Answer to question 7 is: 41 % v/v
The Answer to question 8 is: 9.44 % w/v
The Answer to question 9 is: 6193.64 ml of 14 % , 1376.36 ml of 3 %
The Answer to question 10 is: 1 : 1
The Answer to question 11 is: 78.00 grams
The Answer to question 12 is: 1227.30 ml
The Answer to question 13 is: 2724.00 grams
The Answer to question 14 is: 33.65 ml
The Answer to question 15 is: 68.45 ml
The Answer to question 16 is: 0.99
The Answer to question 17 is: 119.05 ml