1.Easy
Practice exercise (made-up values, not clinical guidance). How many g of dextrose are in 250 mL of 10% w/v solution? Find m.
10% w/v250 mL
m = g
Pharmacy calculations worksheet with answers
2.Easy
A solution is 0.5% w/v. You need 6 mg of the drug. Draw up the volume in the syringe: what volume V is that?
0.5% w/v6 mg
V = mL
3.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 8.2 mL of diluent. The prescribed dose is 2 400 000 units. What volume V do you draw up? Round to one decimal place.
8.2 mL → 500 000 units/mL2 400 000 units
V = mL
4.Medium
A solution has a ratio strength of 1:10 000. You need 0.68 mg. Draw up the volume in the 10 mL syringe: what volume V is that?
1:10 0000.68 mg
V = mL
5.Hard
A vial holds 1000 mg of powder. You add 4.5 mL of diluent, and the powder adds 0.5 mL of volume. The prescription is 500 mg. Draw up the dose: what volume V do you give?
1000 mg4.5 mL + 0.5 mL500 mg
V = mL
6.Hard
Practice exercise (made-up values, not clinical guidance). You have 30 g of 10% salicylic acid ointment. How many grams m of 2% salicylic acid ointment must you add to make a 3% ointment? Round to the nearest whole gram.
30 g · 10%2%3%
m = g
Answer key
- 1. m = 25 g
- 2. V = 1.2 mL
- 3. V = 4.8 mL
- 4. V = 6.8 mL
- 5. V = 2.5 mL
- 6. m = 210 g
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