Practice problems
| # | Question |
|---|---|
| 1 | How many milliliters of water should be added to 110 ml of a 86 % (w/v) solution to prepare 7 % w/v solution? |
| 2 | If 245 ml of a 45 % v/v solution is diluted to 2300 ml , what is the percent strength of the diluted solution? |
| 3 | If 780 ml of a 1 : 212 (w/v) solution is diluted to 2900 ml, what is the ratio strength of the new solution? |
| 4 | If 9 ml of a 0.50 % nasal spray was diluted with 8 ml of normal saline solution, what would be the final drug concentration? |
| 5 | How many milliliters of a 37 % elixir can be prepared from 40 ml of a 64 % elixir? |
| 6 | If a cough syrup contains 11 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 6 mg/ml? |
| 7 | What is the percentage strength (v/v) of an alcohol mixture that has a mix of 400 ml of 45 % alcohol, 150 ml of 70 % alcohol, and 270 ml of 15 % alcohol? |
| 8 | A pharmacist combines 5 pints of a 5 % w/v povidone-iodine solution with 8 quarts of 10 % w/v povidone-iodine solution. What is the strength of the resulting solution? |
| 9 |
How many milliliters of 5 % and a 15 % solution do you need to prepare 1 gallon of 12 % solution? |
| 10 |
What proportion of 20 % 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 940 g of 0.1 % hydrocortisone cream to make a 0.50 % hydrocortisone cream? |
| 12 |
How many milliliters of water should be added to 3.75 L of 1: 1100 w/v solution to make a 1: 6700 w/v solution? |
| 13 |
How many grams of a 3.50 % w/w benzocaine ointment can be prepared by diluting 1 lb of a 35 % w/w benzocaine ointment with white petrolatum? |
| 14 |
How many milliliters of a
12 % 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 210 ml of 72 % (w/v) lactic acid solution? |
| 16 |
What is the specific gravity of a mixture containing 700 ml of water, 1100 ml of glycerin having a specific gravity of 1.25, and 1100 ml of alcohol having a specific gravity of 0.81? |
| 17 |
How many milliliters of a syrup having a specific gravity of 1.41 should be mixed with 3500 mL of a syrup having a specific gravity of 1.30 to obtain a product having a specific gravity of 1.31? |
Answers
The Answer to question 1 is: 1241.43 ml
The Answer to question 2 is: 4.79 % v/v
The Answer to question 3 is: 1 : 788
The Answer to question 4 is: 0.26 %
The Answer to question 5 is: 69.19 ml
The Answer to question 6 is: 228.00 mg
The Answer to question 7 is: 40 % v/v
The Answer to question 8 is: 8.81 % w/v
The Answer to question 9 is: 2649.50 ml of 15 % , 1135.50 ml of 5 %
The Answer to question 10 is: 1 : 2
The Answer to question 11 is: 83.56 grams
The Answer to question 12 is: 19090.90 ml
The Answer to question 13 is: 4540.00 grams
The Answer to question 14 is: 87.96 ml
The Answer to question 15 is: 147.01 ml
The Answer to question 16 is: 1.02
The Answer to question 17 is: 350.00 ml