Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 210 ml of a 74 % (w/v) solution to prepare 15 % w/v solution? |
| 2 | If 790 ml of a 65 % v/v solution is diluted to 2600 ml , what is the percent strength of the diluted solution? |
| 3 | If 210 ml of a 1 : 262 (w/v) solution is diluted to 2000 ml, what is the ratio strength of the new solution? |
| 4 | If 22 ml of a 0.50 % nasal spray was diluted with 20 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 6 % elixir can be prepared from 40 ml of a 71 % elixir? |
| 6 | If a cough syrup contains 3 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 10 mg/ml? |
| 7 | What is the percentage strength (v/v) of an alcohol mixture that has a mix of 250 ml of 30 % alcohol, 200 ml of 60 % alcohol, and 130 ml of 20 % alcohol? |
| 8 | A pharmacist combines 6 pints of a 5 % w/v povidone-iodine solution with 6 quarts of 10 % w/v povidone-iodine solution. What is the strength of the resulting solution? |
| 9 |
How many milliliters of 7 % and a 16 % solution do you need to prepare 4 gallon of 8 % solution? |
| 10 |
What proportion of 25 % zinc oxide and 35 % zinc oxide do you need to make 30 % zinc oxide? |
| 11 |
How many grams of 5 % hydrocortisone cream be mixed with 580 g of 0.75 % hydrocortisone cream to make a 1.50 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 2.50 L of 1: 3500 w/v solution to make a 1: 5100 w/v solution? |
| 13 |
How many grams of a 8.50 % 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
13 % 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 710 ml of 64 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 100 ml of water, 1450 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 1.54 should be mixed with 6000 mL of a syrup having a specific gravity of 1.11 to obtain a product having a specific gravity of 1.41? |
Answers
The Answer to question 1 is: 826.00 ml
The Answer to question 2 is: 19.75 % v/v
The Answer to question 3 is: 1 : 2495
The Answer to question 4 is: 0.26 %
The Answer to question 5 is: 473.33 ml
The Answer to question 6 is: 564.00 mg
The Answer to question 7 is: 38 % v/v
The Answer to question 8 is: 8.33 % w/v
The Answer to question 9 is: 1682.22 ml of 16 % , 13457.78 ml of 7 %
The Answer to question 10 is: 1 : 1
The Answer to question 11 is: 124.29 grams
The Answer to question 12 is: 1142.90 ml
The Answer to question 13 is: 1068.24 grams
The Answer to question 14 is: 173.08 ml
The Answer to question 15 is: 441.81 ml
The Answer to question 16 is: 1.07
The Answer to question 17 is: 13846.15 ml