Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 70 ml of a 36 % (w/v) solution to prepare 11 % w/v solution? |
| 2 | If 315 ml of a 65 % v/v solution is diluted to 2500 ml , what is the percent strength of the diluted solution? |
| 3 | If 800 ml of a 1 : 136 (w/v) solution is diluted to 1100 ml, what is the ratio strength of the new solution? |
| 4 | If 11 ml of a 6.50 % nasal spray was diluted with 8 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 26 % elixir can be prepared from 30 ml of a 54 % elixir? |
| 6 | If a cough syrup contains 22 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 30 % alcohol, 225 ml of 75 % alcohol, and 180 ml of 25 % alcohol? |
| 8 | A pharmacist combines 9 pints of a 5 % w/v povidone-iodine solution with 7 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 12 % solution? |
| 10 |
What proportion of 20 % zinc oxide and 40 % zinc oxide do you need to make 25 % zinc oxide? |
| 11 |
How many grams of 2 % hydrocortisone cream be mixed with 300 g of 0.25 % hydrocortisone cream to make a 0.50 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 4.50 L of 1: 1200 w/v solution to make a 1: 7500 w/v solution? |
| 13 |
How many grams of a 7.50 % w/w benzocaine ointment can be prepared by diluting 1 lb of a 20 % 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 400 ml of 70 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 100 ml of water, 550 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 1.45 should be mixed with 4500 mL of a syrup having a specific gravity of 1.15 to obtain a product having a specific gravity of 1.21? |
Answers
The Answer to question 1 is: 159.09 ml
The Answer to question 2 is: 8.19 % v/v
The Answer to question 3 is: 1 : 187
The Answer to question 4 is: 3.76 %
The Answer to question 5 is: 62.31 ml
The Answer to question 6 is: 276.00 mg
The Answer to question 7 is: 43 % v/v
The Answer to question 8 is: 8.04 % w/v
The Answer to question 9 is: 6728.89 ml of 13 % , 841.11 ml of 4 %
The Answer to question 10 is: 3 : 1
The Answer to question 11 is: 50.00 grams
The Answer to question 12 is: 23625.00 ml
The Answer to question 13 is: 1210.67 grams
The Answer to question 14 is: 88.38 ml
The Answer to question 15 is: 272.24 ml
The Answer to question 16 is: 0.94
The Answer to question 17 is: 1125.00 ml