1.Upstream of a discharge point, a stream has a discharge of 400 cfs and a BOD5 of 12.5 mg/L. A pipe discharges 150 gpm of water containing 120 mg/L of BOD5. What is the downstream BOD5?
2.A batch system is assumed to be first order. The initial concentration is 225 mg/L. If the reaction rate constant is 0.65 hr^-1, how long will it take for the concentration to be one-quarter the starting concentration?
3.If 5 mg of NaOCl are added to one liter of water and the pH is measured to be 7.8, what is the concentration of hypochlorite ion (OCl-) in mg/L?
4.Apoint charge of -4.00 nC is located at (0,1.00) m . what is the x component of the electric field due to the point charge at (4.00, - 2.00) m ?