Practice exercise (made-up values, not clinical guidance). 1.125 g of sodium chloride is dissolved in water to a total volume of 250 mL. What is the percentage strength p (% w/v)?
Pharmacy calculations worksheet with answers
A solution is 5% w/v. You need 95 mg of the drug. Draw up the volume in the syringe: what volume V is that?
A solution has a ratio strength of 1:10 000. You need 0.38 mg. Draw up the volume in the 10 mL syringe: what volume V is that?
A solution has a ratio strength of 1:1000. You need 0.57 mg. Draw up the volume in the 1 mL syringe: what volume V is that?
A vial holds 250 mg of powder. You add 4.8 mL of diluent, and the powder adds 0.2 mL of volume. The prescription is 60 mg. Draw up the dose: what volume V do you give?
A vial holds 250 mg of powder. You add 9.2 mL of diluent, and the powder adds 0.8 mL of volume. The prescription is 117.5 mg. Draw up the dose: what volume V do you give?
Answer key
- 1. p = 0.45 %
- 2. V = 1.9 mL
- 3. V = 3.8 mL
- 4. V = 0.57 mL
- 5. V = 1.2 mL
- 6. V = 4.7 mL
Full step-by-step solutions: practise this topic on examproblems.com.