Problem $1(15$pts$)$

Industrial wastewater effluent is discharged into a $1\mathrm{.}0{10}^9{m}^3$ lake and contains $7\mathrm{.}0{10}^{-6}M$ benzene $(C_6{H}_6).$ The industrial wastewater discharge stream has a flowrate of $8\frac{m^3}{s}.$ The stream feeding the lake has a benzene concentration of $1\mathrm{.}0\frac{g}{L}$ and a flowrate of $100\frac{m^3}{s}.$ Benzene has a decay rate of $0\mathrm{.}038$ day ${?}^{-1}.$

a$)$ What order is the reaction rate?

b$)$ What is the concentration of benzene in $\frac{g}{L}$ in the lake after mixing?

c$)$ What is the maximum contaminant limit $($MCL$)$ for benzene $($check Table $6-1)?$ Does the concentration you calculated in $($b$)$ meet the MCL set by the Safe Drinking Water Act?

Draw a diagram, write governing equations, and state all assumptions.

Problem $3(15$ pts$)$

Ethanol $(C_2{H}_{6}O)$ is produced from agricultural crops and is often added to gasoline. This decreases the amount of crude oil that must be imported and reduces the exhaust emissions. Ethanol combines with $O_2$ in a combustion reaction to produce $C{O}_2$ and $H_{2}O.$

a$)$ Write a balanced chemical equation for the complete combustion of ethanol.

b$)$ Determine the mass of $O_2($in grams$)$ consumed if $200g$ of ethanol are ignited. Show all your work.