1.Easy
Practice exercise (made-up values, not clinical guidance). How many g of dextrose are in 20 mL of 50% w/v solution? Find m.
50% w/v20 mL
m = g
Pharmacy calculations worksheet with answers
2.Easy
A solution is 5% w/v. You need 175 mg of the drug. Draw up the volume in the syringe: what volume V is that?
5% w/v175 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 18.2 mL of diluent. The prescribed dose is 300 000 units. What volume V do you draw up? Round to one decimal place.
18.2 mL → 250 000 units/mL300 000 units
V = mL
4.Medium
A solution has a ratio strength of 1:10 000. You need 0.6 mg. Draw up the volume in the 10 mL syringe: what volume V is that?
1:10 0000.6 mg
V = mL
5.Hard
A vial holds 500 mg of powder. You add 4.8 mL of diluent, and the powder adds 0.2 mL of volume. The prescription is 300 mg. Draw up the dose: what volume V do you give?
500 mg4.8 mL + 0.2 mL300 mg
V = mL
6.Hard
A vial holds 250 mg of powder. You add 9.6 mL of diluent, and the powder adds 0.4 mL of volume. The prescription is 90 mg. Draw up the dose: what volume V do you give?
250 mg9.6 mL + 0.4 mL90 mg
V = mL
Answer key
- 1. m = 10 g
- 2. V = 3.5 mL
- 3. V = 1.2 mL
- 4. V = 6 mL
- 5. V = 3 mL
- 6. V = 3.6 mL
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