Pharmacy Calculations Quizzes

1. An injection for dental anesthesia contains 4% (w/v) of prilocaine hydrochloride and 1:200,000 (w/v) of epinephrine. Express the concentration of epinephrine as a percentage. Answer to the fourth decimal place

0.0005

1. A formula for 1,000 ml contains:Ingredient A 48 gIngredient B 1.3 gAlcohol qs ad 1,000 ml If you want to prepare 50 ml of the formula above, how many grams would you need of ingredient B?

0.0065

1. What is the percentage of a solution of a drug at a ratio of 1:15,000? Answer to the fourth decimal place

0.0066

What is the change in pH on adding 0.02 mol of sodium hydroxide to a liter of a buffer solution containing 0.5 M of sodium acetate and 0.5M acetic acid? The pKa value of acetic acid is 4.76 at 25°C.

0.03

1. How many grams of sodium chloride should be used in compounding the following prescription? Homatropine Hydrobromide 0.6 g (E=0.17)Sodium Chloride qsPurified water qs 30mLMake isotonic solution

0.168

What is the change in pH with the addition of 0.01 mol hydrochloric acid to a liter of a buffer solution containing 0.05 M of ammonia and 0.05 M of ammonium chloride? The Kb value of ammonia is 1.80 ×10−5 at 25°C - Careful here! Kb is not pKb!

0.17

Calculate the change in pH after adding 0.04 mol of sodium hydroxide to a liter of a buffer solution containing 0.2 M of sodium acetate and 0.2 M of acetic acid. The pKa value of acetic acid is 4.76 at 25°C.

0.18

1. Ketorolac ophthalmic solution 0.5%Disp. 5 mLSig: One drop q.i.d. prn allergic conjunctivitis How many milligrams of the active constituent would be present in each drop of the ophthalmic solution if the dropper delivers 20 drops per milliliter?

0.25 mg

What is the concentration, in grams per milliliter, of a solution containing 4 mEq of calcium chloride per milliliter? Answer with three decimal places. CaCl2 · 2H2O MW = 147, V = 2, generates 3 ions.

0.294

Sodium Phosphate, dibasic 6.2 g Sodium Phosphate, monobasic 4.5 g Water q.s. 1000 mL What is the pH change in this buffer if 3 mL of a 5-M hydrochloric acid solution are added to the buffer? Assume negligible volume displacement by the hydrochloric acid solution. The pKa value of sodium phosphate monobasic is 7.21 at 25°C and serves as an acid in this buffer because it is more acidic than sodium phosphate dibasic. The molecular weight of sodium phosphate monobasic is 120 and of sodium phosphate dibasic is 142.

0.33

A pharmacist received a medication order to add 40,000 units of heparin sodium to 1 L of dextrose 5% in water for a 180 lb patient. The rate of the infusion was prescribed as 2000 units/h. What is the dose of heparin sodium received by the patient, on a unit/kg/minute basis? Answer with two decimal places.

0.41

1. An electrolyte solution has the following formula: Sodium chloride 9.4 g Potassium chloride 0.5 g Calcium chloride 0.45 g PEG 3350 70.0 g Water for injection ad 1,000 ml Assuming that 950 ml of water are used in preparing the irrigation, calculate its specific gravity

1.03

Serum lactate (MW = 89, Valence = 1) concentration is 15 mg/dL. Express this concentration in mEq/L with two decimal places.

1.69

1. Isotonic sodium chloride solution contains 0.9% w/v sodium chloride. If the E-value of boric acid is 0.52, calculate the percentage strength (w/v) of an isotonic solution of boric acid.

1.73

How many grams of calcium chloride would be needed to prepare 100 mL of a solution containing 50 mOsmol? Answer with two decimal places.CaCl2 MW = 111, V = 2, generates 3 ions.

1.85

What molar ratio of salt/acid is required to prepare a sodium acetate/acetic acid buffer solution with a pH of 5.76? The pKa value of acetic acid is 4.76 at 25°C. Answer with an integer. Example: Answer 6 (instead of 6/1 or 6:1) or 22 ( instead of 22/1 or 22:1)

10

What is the pH of a buffer solution prepared with 0.05 M sodium borate and 0.005 M boric acid? The pKa value of boric acid is 9.24 at 25°C

10.24

Calculate the osmolarity in mOsmols/L of a 3% sodium chloride solution. Answer with two decimal places. NaCl MW = 58.5, V = 1, generates 2 ions.

1025.64

How many mg of potassium chloride are in two 8 mEq tablets of Klor-Con (KCl) tablets? MW of KCL = 74.5

1192

1. If 100 mL of a solution contains 250 mg of a drug, how many milligrams of the drug will be in a 5mL dose taken by a patient?

12.5

A physician writes an order for micafungin 50 mg in 100 mL 0.9% NaCl to be administered over 1 h in an infusion set that delivers 10 gtt/mL. Reconstitution with 5 mL of 0.9% NaCl results in a micafungin concentration of 20 mg/mL. How many drops per minute should be administered to deliver 50 mg of micafungin? Round to the next integer.

17

How many grams of sodium chloride should be used in preparing 20 liters of a solution containing 154 mEq/L? NaCl MW = 58.5, V = 1, generates 2 ions. Answer with two decimal places.

180.18

1. How many grams of sucrose are necessary to prepare 1 gallon of a 5% solution? Consider 1 gallon = 3.785L and answer with two decimal places.

189.25

1. If 50 g of a drug are present in a total of 1 liter of solution, what is the ratio strength? Your answer should look like "x:y", no spaces.

1:20

1. A formula for 1,000 ml contains: Ingredient A 48 g Ingredient B 1.3 g Alcohol qs ad 1,000 ml If you want to prepare 50 ml of the formula above, how many grams would you need of ingredient A?

2.4

1. How many grams of atropine I will need to prepare 250 mL of a 1% solution?

2.5

1. If 500 mL of a 5% (w/v) solution are diluted to 1 L, what is the new percentage strength (w/v) of the preparation.

2.5

Serum calcium (MW = 40.1) concentration is expressed as mg/dL on the biochemical profile. Express a 10 mg/dL serum calcium concentration in mmol/L. Answer with one decimal place.

2.5

A pharmacist received a medication order to add 40,000 units of heparin sodium to 1 L of dextrose 5% in water for a 180 lb patient. The rate of the infusion was prescribed as 2000 units/h. How long will the infusion run, in hours?

20

1. Ephedrine sulfate 0.3 g (E-Value = 0.23)Sodium chloride qs Purified water qs 30 mL Make isoton. sol.Sig. use as directed How many milligrams of sodium chloride should be used in compounding the prescription? Please answer with a whole number, no decimals.

201

1. How many mg of sodium chloride should be used in compounding this prescription? Answer with two decimal places. Benoxinate Hydrochloride 0.4% w/v (E=0.17)Fluorescein Sodium 0.25% w/v (E=0.31)Sodium chloride qsPurified water qs 30 mL Make an isotonic solution

226.35

1. Given the following formula for 100 prednisone capsules, how many milligrams of prednisone would be required to make 30 capsules? Prednisone 80 mg Lactose 5 g

24

A few years ago there was a shortage of sterile 0.9% sodium chloride solution (normal saline - NS) in the United States, forcing pharmacists around the country to sometimes prepare it by dilution from vials of concentrated sodium chloride. How many milliliters of NS can be made using two 50 mL vials, each containing 23.4% of sodium chloride?

2600

What is the osmolarity (mOsmole/L) of a 5% dextrose solution? (MW = 180). Round to the nearest whole number.

28

A patient is receiving a slow intravenous infusion containing 40 mEq of potassium chloride in 1000 mL of fluid. If, after 12 hours, 720 mL of infusion had been infused, how many millimoles of potassium chloride were administered? Answer with one decimal place. KCl MW = 74.5, V = 1, generates 2 ions.

28.8

1. If 4 tablets contain 960 milligrams of aspirin, how many milligrams should be contained in 12 tablets?

2880

A physician prescribes 3 mEq/kg of NaCl to be administered to a 165-lbpatient. How many milliliters of a half-normal saline solution (0.45%NaCl) should be administered? NaCl MW = 58.5, V = 1, generates 2 ions.

2925

What is the concentration (in mg/mL) of a solution containing 4 mEq/mL of KCl (MW =74.5)?

298

A medication order for an IV infusion for a patient weighing 110 lb calls for 0.5 mEq of ammonium chloride per kilogram of body weight to be added to 500 ml of D5W. How many milliliters of a sterile solution containing 100 mEq of ammonium chloride per 20 ml should be used in preparing the infusion?

3

A medication order for a patient weighing 154 lb. calls for 0.25 mg of amphotericin B per kilogram of body weight to be added to 500 mL of 5% dextrose injection. If the amphotericin B comes from a vial containing 50 mg/10 mL, how many milliliters of this vial should be added to the dextrose injection? Answer with one decimal place

3.5

1. If 100g of a preparation contains 3mg of a drug, the drug concentration in ppm is:

30

1. If 5mL of a medicated suspension contains 250 mg of drug, how many milligrams of drug will be in 2 fl oz of suspension? (use 1 fl oz =30 mL)

3000

How many mEq of sodium chloride are in a 250-mL bag of D5NS* for intravenous infusion? Answer with two decimal places. *D5NS = Dextrose 5% in Normal Saline NaCl MW = 58.5, V = 1, generates 2 ions.

38.46

1. A pharmacist had 5 g of promethazine HCl. How many grams were left after he compounded the following prescriptions? Answer with one decimal place. ℞1: 6 suppositories each containing 10 mg ℞2: 6 suppositories each containing 25 mg ℞3: 10 suppositories each containing 40 mg

4.40

1. Dextrose anhydrous 2.5% (E=0.18)Sodium Chloride q.s.Sterile water for injection ad 1000 mLLabel: Isotonic dextrose and saline solution How many grams of sodium chloride should be used in preparing this solution?

4.5

1. After a long day of pharmacy school, you decide to treat yourself to an arctic-cold beer. Much to your dismay, when you look at the label you are reminded of Pharmacy Calculations class. The label says that your beer contains 6% alcohol (ethanol) by volume (in other words v/v). If you drink 2 cans of the beer (12 fluidounces each), how many mL of alcohol (ethanol) have you consumed? Consider 1 fluid ounce=30 mL, answer with one decimal place.

43.2

1. If 200 g sodium chloride are dissolved in 250 mL of water, what is the percentage (w/w) of sodium chloride in the solution?

44.44

1. If 50 g of drug are present in 1 liter of a solution, what is the percent (w/v) of the solution?

5

1. You have a 10-ml vial of aminophylline labeled "25 mg per ml". How many milliliters must be injected to administer a dose of 125 mg?

5

What is the pH of a buffer solution prepared with 0.055 M sodium acetate and 0.01 M acetic acid? The pKa value of acetic acid is 4.76 at 25°C. pH = pKa + log (salt/acid)

5.5

1. You are babysitting your neighbor's 16-month old daughter and you have to give her Mylicon® (simethicone) drops for gas. After looking at the label, you again find yourself thinking about your favorite class, Pharmacy Calculations. The label says that there are 20 mg of simethicone in every 0.3 mL of the drops. What is the percent strength (w/w)? The specific gravity of the drops is 1.12. Answer with two decimal places

5.95

1. A pre-filled syringe contains 20 mg of drug in 2 mL of solution. How many micrograms of drug would be administered by an injection of 0.5 mL of the solution?

5000

1. How many milligrams of boric acid should be used in compounding this prescription? E-Values: Boric Acid = 0.52, Zinc Sulfate = 0.15 Zinc sulfate 0.06g Boric acid qsPurified water qs 30 mLMake an isotonic solution

501.92

1. In a clinical study of niacin as a lipid-altering agent, 60% of the 90 patients in the study group developed flushing. Calculate the number of patients having this reaction

54

How many milliosmoles of dextrose are found in two liters of a solution of dextrose 5% in water (D5W)? Dextrose MW = 180, V = none, generates 1 particle Answer with two decimal places.

555.55

A physician ordered 450,000 units of Penicillin G to be added to 100 mL Dextrose 5% in water and infused over 3 h. Assuming that a 10 mL solution results when a vial containing 1 million units of penicillin G potassium is reconstituted and using an IV set that delivers 10 drops/mL, what would be the flow rate in drops per minute? Round to the next integer.

6

1. If a patient received the following doses of a drug in four days, what is the total amount of drug received by the patient in mg? Four doses each containing 0.25 mg Three doses each containing 0.5 mg Two doses each containing 1.25 mg One dose containing 1.5 mg

6.5

1. How many 0.00025 g doses can be prepared with 0.150 g of a pure drug?

600

How many mOsmols of dextrose are in a 250-mL bag of D5NS* for intravenous infusion? *D5NS = Dextrose 5% in Normal Saline Dextrose MW = 180, V = none, generates 1 particle

69.44

1. Calculate the pH of the following buffer: Sodium Phosphate, dibasic 6.2 g Sodium Phosphate, monobasic 4.5 g Water q.s. 1000 mL

7.28

Calculate the total number of drops delivered by 250 mL of an infusion when using an administration sets delivering 15 drops/mL

7500

1. Aspirin tablets generally contain 325 mg of aspirin in each tablet. How many of these tablets can be prepared from 2500 g of aspirin?

7692

1. A certain tablet contains 32.5 mg of phenobarbital. What is the number of milligrams of phenobarbital in 24 tablets?

780

The molar ratio of salt to acid needed to prepare a sodium acetate-acetic acid buffer solution is 1:1. Assuming that the total buffer concentration is 0.1 mol/L, how many grams of sodium acetate (MW = 82) should be used in preparing 2 liters of the solution? The pKa value of acetic acid is 4.76 at 25°C.

8.2

1. If 200 g of sodium chloride are dissolved in enough water to make a final volume of 250 mL, what is the percentage strength (w/v) of sodium chloride in the solution?

80

Potassium chloride for injection comes in 60 ml vials containing 2 mEq/ml. How many milligrams of KCl are in each vial? MW of KCL = 74.5

8940

What is the pH of a buffer solution prepared with 0.05 M ammonia and 0.05 M ammonium chloride? The Kb value of ammonia is 1.80 × 10−5 at25°C

9.26

A 154-lb patient is to receive 36 mg/kg of ammonium chloride. How many milliliters of an ammonium chloride (NH4Cl, MW = 53.5) injection containing 5 mEq/mL should be added to the patient's intravenous infusion? Answer with two decimal places.

9.4

An aluminum hydroxide gel suspension contains 320 mg of aluminum hydroxide in each teaspoonful dose. How many milliequivalents of aluminum would a patient receive each day if he is ingesting two teaspoonfuls of the suspension four times daily? Answer with two decimal places. Al(OH)3, MW=78, V = 3, generates 4 particles.

98.46

1. How many grams of sodium chloride should be used to make the following prescription isotonic? E-value of chlorobutanol = 0.24 Chlorobutanol 0.25% Sodium Chloride q.s. Purified water qs ad 30 mL

DNE

1. Suprax suspension contains 100 mg/5mL of the drug cefixime. If the patient takes one teaspoonful of the suspension twice daily for ten days, how many grams of the drug does the patient consume?

DNE

1. When adding 100 mL of water to 50 mL of alcohol, what would be the final concentration of alcohol v/v in %? Round to two decimal places.

DNE

A local ophthalmologist is treating one of his patients for a post-LASIK eye infection that is not responding to topical ciprofloxacin. These infections, although rare, can occur after laser in situ keratomileusis (LASIK) surgery for vision correction. Topical amikacin sulfate has been shown to be effective for the treatment of eye infections due to ciprofloxacin- resistant Pseudomonas, Burkholderia ambifaria,Mycobacterium chelonae, and Mycobacterium fortuitum. The ophthalmologist prescribes 60 mL of a 2.5% amikacin sulfate isotonic solution, two drops in the affected eye every 2 hours.Amikacin sulfate USP (C22H43N5O13·2H2SO2), m.w., 781.76, E-Value = 0.108, is an aminoglycoside-type antibiotic containing three ions. How many milliliters of 23.5% sodium chloride injection should be used to obtain the amount of sodium chloride needed? Answer with two decimal places.

DNE

PLASMA-LYTE 56 contains 32 mg of magnesium acetate tetrahydrate,128 mg of potassium acetate, and 234 mg of sodium chloride in each 100 mL of solution. What is the osmolarity of this solution? Assume complete dissociation. Magnesium acetate tetrahydrate (Mg(C2H3O2)2 · 4H2O): MW=214 Potassium acetate (KC2H3O2): MW= 98 Sodium chloride: MW= 58.5

DNE

What is the osmolarity (in mOsmoles/L) of one liter of a 50% dextrose solution (MW = 180)? Answer with two decimal places

DNE

1. If you add 118 mg of Zyrtec (cetirizine) to a 4 fl oz bottle of Zyrtec (cetirizine) syrup with an initial concentration of 1 mg/mL, the new concentration would be 3 mg/mL (assume no change in volume) T/F.

fasle

1. We have a solution containing 10g of chloramphenicol sodium succinate (E=0.10) and 0.5g of lidocaine hydrochloride (E=0.22) in 100 mL of an aqueous solution. Is this solution hypotonic, isotonic or hypertonic?

hypertonic