Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 40 ml of a 58 % (w/v) solution to prepare 11 % w/v solution? |
| 2 | If 790 ml of a 60 % v/v solution is diluted to 2500 ml , what is the percent strength of the diluted solution? |
| 3 | If 625 ml of a 1 : 148 (w/v) solution is diluted to 1800 ml, what is the ratio strength of the new solution? |
| 4 | If 33 ml of a 8.00 % nasal spray was diluted with 6 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 49 % elixir can be prepared from 80 ml of a 85 % 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 8 mg/ml? |
| 7 | What is the percentage strength (v/v) of an alcohol mixture that has a mix of 250 ml of 35 % alcohol, 275 ml of 60 % alcohol, and 50 ml of 5 % alcohol? |
| 8 | A pharmacist combines 1 pints of a 5 % w/v povidone-iodine solution with 10 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 2 gallon of 11 % solution? |
| 10 |
What proportion of 10 % zinc oxide and 60 % zinc oxide do you need to make 35 % zinc oxide? |
| 11 |
How many grams of 3 % hydrocortisone cream be mixed with 120 g of 0.25 % hydrocortisone cream to make a 2.00 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 3.50 L of 1: 1400 w/v solution to make a 1: 9900 w/v solution? |
| 13 |
How many grams of a 4.50 % 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 660 ml of 64 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 700 ml of water, 1450 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 1.65 should be mixed with 7500 mL of a syrup having a specific gravity of 1.19 to obtain a product having a specific gravity of 1.24? |
Answers
The Answer to question 1 is: 170.91 ml
The Answer to question 2 is: 18.96 % v/v
The Answer to question 3 is: 1 : 426
The Answer to question 4 is: 6.77 %
The Answer to question 5 is: 138.78 ml
The Answer to question 6 is: 48.00 mg
The Answer to question 7 is: 44 % v/v
The Answer to question 8 is: 9.76 % w/v
The Answer to question 9 is: 4129.09 ml of 16 % , 3440.91 ml of 5 %
The Answer to question 10 is: 1 : 1
The Answer to question 11 is: 210.00 grams
The Answer to question 12 is: 21250.00 ml
The Answer to question 13 is: 1513.33 grams
The Answer to question 14 is: 28.94 ml
The Answer to question 15 is: 410.70 ml
The Answer to question 16 is: 1.03
The Answer to question 17 is: 914.63 ml