Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 200 ml of a 32 % (w/v) solution to prepare 21 % w/v solution? |
| 2 | If 830 ml of a 75 % v/v solution is diluted to 1100 ml , what is the percent strength of the diluted solution? |
| 3 | If 860 ml of a 1 : 78 (w/v) solution is diluted to 900 ml, what is the ratio strength of the new solution? |
| 4 | If 30 ml of a 0.70 % nasal spray was diluted with 26 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 42 % elixir can be prepared from 60 ml of a 48 % elixir? |
| 6 | If a cough syrup contains 37 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 350 ml of 45 % alcohol, 150 ml of 55 % alcohol, and 160 ml of 20 % alcohol? |
| 8 | A pharmacist combines 2 pints of a 5 % w/v povidone-iodine solution with 3 quarts of 10 % w/v povidone-iodine solution. What is the strength of the resulting solution? |
| 9 |
How many milliliters of 4 % and a 18 % solution do you need to prepare 2 gallon of 12 % solution? |
| 10 |
What proportion of 20 % zinc oxide and 90 % zinc oxide do you need to make 70 % zinc oxide? |
| 11 |
How many grams of 3 % hydrocortisone cream be mixed with 760 g of 0.1 % hydrocortisone cream to make a 1.50 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 2.75 L of 1: 3100 w/v solution to make a 1: 7400 w/v solution? |
| 13 |
How many grams of a 5.50 % 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
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 830 ml of 52 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 300 ml of water, 750 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 1.56 should be mixed with 6000 mL of a syrup having a specific gravity of 1.21 to obtain a product having a specific gravity of 1.40? |
Answers
The Answer to question 1 is: 104.76 ml
The Answer to question 2 is: 56.59 % v/v
The Answer to question 3 is: 1 : 82
The Answer to question 4 is: 0.38 %
The Answer to question 5 is: 68.57 ml
The Answer to question 6 is: 96.00 mg
The Answer to question 7 is: 41 % v/v
The Answer to question 8 is: 8.75 % w/v
The Answer to question 9 is: 4325.71 ml of 18 % , 3244.29 ml of 4 %
The Answer to question 10 is: 2 : 5
The Answer to question 11 is: 709.33 grams
The Answer to question 12 is: 3814.50 ml
The Answer to question 13 is: 2063.64 grams
The Answer to question 14 is: 25.61 ml
The Answer to question 15 is: 419.64 ml
The Answer to question 16 is: 0.97
The Answer to question 17 is: 7125.00 ml