1.Easy
Practice exercise (made-up values, not clinical guidance). 50 g of dextrose is dissolved in water to a total volume of 500 mL. What is the percentage strength p (% w/v)?
50 g500 mL
p = %
Pharmacy calculations worksheet with answers
2.Easy
Practice exercise (made-up values, not clinical guidance). 125 g of dextrose is dissolved in water to a total volume of 250 mL. What is the percentage strength p (% w/v)?
125 g250 mL
p = %
3.Medium
Practice exercise (made-up values, not clinical guidance). A vial contains cefazolin 1000 mg as a powder. The practice label says to add 4.5 mL of sterile water; the powder adds 0.5 mL to the volume. What is the concentration C in mg/mL after reconstitution?
1000 mg4.5 mL+0.5 mL
C = mg/mL
4.Medium
A solution has a ratio strength of 1:1000. You need 0.23 mg. Draw up the volume in the 1 mL syringe: what volume V is that?
1:10000.23 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 100 mg. Draw up the dose: what volume V do you give?
500 mg4.8 mL + 0.2 mL100 mg
V = mL
6.Hard
A vial holds 1000 mg of powder. You add 2.1 mL of diluent, and the powder adds 0.4 mL of volume. The prescription is 600 mg. Draw up the dose: what volume V do you give?
1000 mg2.1 mL + 0.4 mL600 mg
V = mL
Answer key
- 1. p = 10 %
- 2. p = 50 %
- 3. C = 200 mg/mL
- 4. V = 0.23 mL
- 5. V = 1 mL
- 6. V = 1.5 mL
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