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Consider the air over a city to be a box 100 km on a side that reaches up to an

ID: 1921136 • Letter: C

Question

Consider the air over a city to be a box 100 km on a side that reaches up to an altitude of 1.0 km. Clean air is blowing into the box along one of its sides with a speed of 4 m/s. Suppose an air pollutant with rate constant k= 0.20/hr is emitted into the box at a total rate of 10.0 kg/s. Find the steady-state concentration if the air is assumed to be completely mixed. Consider the air over a city to be a box 100 km on a side that reaches up to an altitude of 1.0 km. Clean air is blowing into the box along one of its sides with a speed of 4 m/s. Suppose an air pollutant with rate constant k= 0.20/hr is emitted into the box at a total rate of 10.0 kg/s. Find the steady-state concentration if the air is assumed to be completely mixed. Consider the air over a city to be a box 100 km on a side that reaches up to an altitude of 1.0 km. Clean air is blowing into the box along one of its sides with a speed of 4 m/s. Suppose an air pollutant with rate constant k= 0.20/hr is emitted into the box at a total rate of 10.0 kg/s. Find the steady-state concentration if the air is assumed to be completely mixed.

Explanation / Answer

V= 100*100*1 = 10000 km^3
Q = 4/1000*1*100 = 0.4 km^3/s
m (loading) = 10kg/s, k = 0.20/hr
1 km^3 = 10^12 L (if u want kg/L as concentration)

Cin = 10kg/s / 0.4 km^3/s = 25 kg/km^3

for CSTR: Cout = Cin/(1+k*t), t = V/Q = 25000 s or 6.94 hr

Cout = 25/(1+0.20*6.94) = 10.47 kg/km^3