Final answer:
The maximum permissible molarity of antimony discharged as antimony trioxide (Sb2O3) in the sewer system, as regulated by the EPA, is 2.06 × 10^-5 M when the concentration limit for antimony is 6.0 µg/L.
Step-by-step explanation:
The US Environmental Protection Agency (EPA) sets limits on the quantities of toxic substances that may be discharged into the sewer system, such as antimony, which is limited to 6.0 µg/L. To calculate the maximum permissible molarity of antimony discharged as antimony trioxide (Sb2O3), we can use the molar mass of antimony trioxide and the given concentration limit.
Firstly, we need to convert the limit from micrograms per liter (µg/L) to milligrams per liter (mg/L), since molarity is based on moles per liter and molar mass is typically given in g/mol. 1 µg/L is equal to 0.001 mg/L, so the limit for antimony in mg/L is 0.006 mg/L.
Next, we determine the molar mass of Sb2O3. The molar mass of antimony (Sb) is approximately 121.76 g/mol, and the molar mass of oxygen (O) is approximately 16.00 g/mol. Therefore, the molar mass of Sb2O3 is:
(2 × 121.76 g/mol) + (3 × 16.00 g/mol) = 291.52 g/mol
To find the molarity, we divide the mass limit per liter by the molar mass:
0.006 mg/L ÷ 291.52 mg/mmol = 2.06 × 10 - 5 M
Thus, the maximum permissible molarity of antimony trioxide in the discharge is 2
.0 6 x 1 0- 5 M