Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 230 ml of a 46 % (w/v) solution to prepare 26 % w/v solution? |
| 2 | If 660 ml of a 80 % v/v solution is diluted to 2800 ml , what is the percent strength of the diluted solution? |
| 3 | If 630 ml of a 1 : 114 (w/v) solution is diluted to 2500 ml, what is the ratio strength of the new solution? |
| 4 | If 29 ml of a 5.00 % nasal spray was diluted with 16 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 17 % elixir can be prepared from 35 ml of a 67 % elixir? |
| 6 | If a cough syrup contains 4 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 400 ml of 30 % alcohol, 200 ml of 55 % alcohol, and 390 ml of 5 % alcohol? |
| 8 | A pharmacist combines 7 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 4 % and a 12 % solution do you need to prepare 4 gallon of 8 % solution? |
| 10 |
What proportion of 20 % zinc oxide and 50 % zinc oxide do you need to make 40 % zinc oxide? |
| 11 |
How many grams of 4 % hydrocortisone cream be mixed with 840 g of 0.75 % hydrocortisone cream to make a 2.50 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 4.75 L of 1: 900 w/v solution to make a 1: 5500 w/v solution? |
| 13 |
How many grams of a 6.50 % 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
21 % 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 630 ml of 30 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 800 ml of water, 1250 ml of glycerin having a specific gravity of 1.25, and 1000 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 1500 mL of a syrup having a specific gravity of 1.18 to obtain a product having a specific gravity of 1.32? |
Answers
The Answer to question 1 is: 176.92 ml
The Answer to question 2 is: 18.86 % v/v
The Answer to question 3 is: 1 : 452
The Answer to question 4 is: 3.22 %
The Answer to question 5 is: 137.94 ml
The Answer to question 6 is: 372.00 mg
The Answer to question 7 is: 25 % v/v
The Answer to question 8 is: 7.67 % w/v
The Answer to question 9 is: 7570.00 ml of 12 % , 7570.00 ml of 4 %
The Answer to question 10 is: 1 : 2
The Answer to question 11 is: 980.00 grams
The Answer to question 12 is: 24277.80 ml
The Answer to question 13 is: 1047.69 grams
The Answer to question 14 is: 34.39 ml
The Answer to question 15 is: 183.76 ml
The Answer to question 16 is: 1.04
The Answer to question 17 is: 750.00 ml