CHEMISTRY 31

Quiz 1 - KEY

Sept. 7

The concentration of a solution of sildenafil (or Viagra, molecular weight = 474.6 g/mol) was found to be 87.1 ppm (parts per million by weight). If the density of the solution is 1.02 g/mL, calculate the concentration in μM.

We want to get the concentration in μM which is μmol sildenafil/L sol’n

Conc. = (87.1 g sildenafil/10⁶ g sol’n)∙(1.02 g sol’n/mL sol’n)∙

(1 mol sildenafil /474.6 g sildenafil)∙(1000 mL/1 L)∙(10⁶ mol/1 mol)

Conc. = 187 μmol sildenafil/L sol’n = 187 μM