Question

Solution Calculations for Celecoxib / C₁₇H₁₄F₃N₃O₂S

Directions: Clearly show the setups for your calculations.

1. You wish to prepare 50.0 mL of 2.30 x 10–2 M solution of your drug. Describe how to prepare this solution from the pure drug and deionized water. Analytical balances and volumetric flasks are available to you. (Assume that your drug dissolves in water, at least to the extent necessary for this problem.) Show any required calculations you would need to make.

2. Calculate how many milligrams of the drug are contained in 2.0 mL of a 3.0 % (wt/vol) solution of your drug

Answer 1

Q1. volume of solution = 50.0 mL

volume of solution = 50.0 mL * (1.00 L / 1000 mL)

volume of solution = 5.00 x 10^-2 L

molarity of drug = 2.30 x 10^-2 M

moles of drug = (molarity of drug) * (volume of solution)

moles of drug = (2.30 x 10^-2 M) * (5.00 x 10^-2 L)

moles of drug = 1.15 x 10^-3 mol

mass of drug = (moles of drug) * (molar mass C₁₇H₁₄F₃N₃O₂S)

mass of drug = (1.15 x 10^-3 mol) * (381.37 g/mol)

mass of drug = 0.445 g

To prepare the required solution, dissolve 0.445 g of drug in 50.0 mL deionized water.

Q2. Concentration of drug = 3.0 % (wt/vol) = 3.0 g drug/100 mL solution

volume of solution = 2.0 mL

mass of drug = (volume of solution) * (concentration of drug)

mass of drug = (2.0 mL) * (3.0 g drug/100 mL solution)

mass of drug = 0.060 g

mass of drug = 0.060 g * (1000 mg / 1 g)

mass of drug = 60 mg