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## Homework Statement

Question 2.

Tetraethyl lead was used in early model cars to help reduce engine knocking, boost octane ratings, and help with wear and tear on valveseats within the motor. In Australia, our petrol

contained lead between approximately 1950 and 2002. Consider the impact of lead in petrol on a lake used for drinking water supply. The lake has a steady state water volume of 8.2 x 107m3 with an inflow and outflow of 6.0 x 107m3/year. From 1950, the lead concentration in the lake inflow water was 40 ppb and the deposition rate of lead onto the lake surface was 120 kg/y. Assume the lead concentration in the lake water was zero when lead first started being added to petrol and that the lake is completely mixed.

a.Calculate the steady state concentration of lead in

the lake water (in μg/L) for the time period when lead was included in petrol.

## Homework Equations

I was thinking since output rate = reaction rate... QC = G-kCV

## The Attempt at a Solution

We've got pretty much all of the variables.. Except for C and k...

Rearranging for C...

C = G / (Q + kV)

To find k... k = G/VC

(120kg/year) / 8.2x10^7 * 40 ppb

= 120 kg/year / 8.2*10^10L * 4x10^-8 kg/L

= 120/year / 3936

= 0.0366/year

...

c = 120 kg/year / 6.0*10^7 m3/year + 0.0366/year * 8.2*10^7m3

However I get some ridiculous number.