1.Easy
Practice exercise (made-up values, not clinical guidance). How many g of sodium chloride are in 250 mL of 3% w/v solution? Find m.
3% w/v250 mL
m = g
Pharmacy calculations worksheet with answers
2.Easy
A solution is 2% w/v. You need 26 mg of the drug. Draw up the volume in the syringe: what volume V is that?
2% w/v26 mg
V = mL
3.Medium
Practice exercise (made-up values, not clinical guidance). A vial contains ceftriaxone 1000 mg as a powder. The practice label says to add 9.6 mL of sterile water; the powder adds 0.4 mL to the volume. The prescribed dose is 600 mg. What volume V do you draw up? Round to one decimal place.
1000 mg9.6 mL+0.4 mL600 mg
V = mL
4.Medium
Practice exercise (made-up values, not clinical guidance). A vial of penicillin G contains 5 000 000 units. Its practice label gives three strengths (see the table). You add 18.2 mL of diluent. The prescribed dose is 1 500 000 units. What volume V do you draw up? Round to one decimal place.
18.2 mL → 250 000 units/mL1 500 000 units
V = mL
5.Hard
Practice exercise (made-up values, not clinical guidance). You have 120 g of 5% coal tar ointment. How many grams m of 1% coal tar ointment must you add to make a 3% ointment? Round to the nearest whole gram.
120 g · 5%1%3%
m = g
6.Hard
A vial holds 1000 mg of powder. You add 4.8 mL of diluent, and the powder adds 0.2 mL of volume. The prescription is 240 mg. Draw up the dose: what volume V do you give?
1000 mg4.8 mL + 0.2 mL240 mg
V = mL
Answer key
- 1. m = 7.5 g
- 2. V = 1.3 mL
- 3. V = 6 mL
- 4. V = 6 mL
- 5. m = 120 g
- 6. V = 1.2 mL
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