1.Easy
A solution is 2% w/v. You need 38 mg of the drug. Draw up the volume in the syringe: what volume V is that?
2% w/v38 mg
V = mL
Pharmacy calculations worksheet with answers
2.Easy
A solution is 1% w/v. You need 11 mg of the drug. Draw up the volume in the syringe: what volume V is that?
1% w/v11 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 1 500 000 units. What volume V do you draw up? Round to one decimal place.
8.2 mL → 500 000 units/mL1 500 000 units
V = mL
4.Medium
A solution has a ratio strength of 1:10 000. You need 0.84 mg. Draw up the volume in the 10 mL syringe: what volume V is that?
1:10 0000.84 mg
V = mL
5.Hard
Practice exercise (made-up values, not clinical guidance). You have 20 g of 5% coal tar ointment. How many grams m of 1% coal tar ointment must you add to make a 2% ointment? Round to the nearest whole gram.
20 g · 5%1%2%
m = g
6.Hard
Practice exercise (made-up values, not clinical guidance). You must prepare 250 mL of 40% dextrose by mixing 70% and 10% dextrose. How many mL V of the 70% solution do you need? Round to the nearest whole mL.
70%10%40%250 mL
V = mL
Answer key
- 1. V = 1.9 mL
- 2. V = 1.1 mL
- 3. V = 3 mL
- 4. V = 8.4 mL
- 5. m = 60 g
- 6. V = 125 mL
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