1.Easy
Practice exercise (made-up values, not clinical guidance). 0.9 g of sodium chloride is dissolved in water to a total volume of 100 mL. What is the percentage strength p (% w/v)?
0.9 g100 mL
p = %
Pharmacy calculations worksheet with answers
2.Easy
Practice exercise (made-up values, not clinical guidance). How many g of sodium chloride are in 100 mL of 0.9% w/v solution? Find m.
0.9% w/v100 mL
m = g
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 0.82 mg. Draw up the volume in the 10 mL syringe: what volume V is that?
1:10 0000.82 mg
V = mL
5.Hard
Practice exercise (made-up values, not clinical guidance). You must prepare 600 mL of 5% sodium chloride by mixing 23% and 3% sodium chloride. How many mL V of the 3% solution do you need? Round to the nearest whole mL.
23%3%5%600 mL
V = mL
6.Hard
A vial holds 1000 mg of powder. You add 9.2 mL of diluent, and the powder adds 0.8 mL of volume. The prescription is 440 mg. Draw up the dose: what volume V do you give?
1000 mg9.2 mL + 0.8 mL440 mg
V = mL
Answer key
- 1. p = 0.9 %
- 2. m = 0.9 g
- 3. V = 1.2 mL
- 4. V = 8.2 mL
- 5. V = 540 mL
- 6. V = 4.4 mL
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