Question

Suppose the average concentration of copper in water is measured to be 2.5 x 10" M. a. Express this concentration in mg/L. b. Express this concentration in ug/L. c. Does this concentration of copper exceed the freshwater acute criteria maximum concentration of 65 ppb?

Answer 1

Answer:

a) C Cu = 1588.6 mg/L

b) C Cu = 1588600 μg/L

c) this concentration exceeds the acute freshwater criteria:

∴ C Cu = 1588.6 mg/L >> 0.065 mg/L

Explanation:

∴ C Cu = 2.5 E-2 mol/L

∴Mw Cu = 63.546 g/mol

a) C Cu = 2.5 E-2 mol/L * 63.546 g/mol = 1.5886 g/L

⇒ C Cu = 1.5886 g/L * ( 1000 mg/g ) = 1588,6 mg/L

b) C Cu =  1588.6 mg/L * ( μg / 0.001 mg ) = 1588600 μg/L

c) C Cu = 65 ppb * ( ppm / 1000ppb ) = 0.065 ppm = 0.065 mg/L

∴ ppm ≡ mg/L

⇒ C Cu = 1588.6 mg/L >> 0.065 mg/L; this concentration exceeds the acute freshwater criteria