Question

The sulfur dioxide (so2) stack-gas concentration from fossil-fuel combustion is 12 ppmv. determine the stack-gas so2 concentration in units of µg/m3. assume 0 °c and 1 atm pressure. express answer to nearest unit.

Answer 1

The concentration of $SO_{2}$ in the stack gas = 12 ppmv

That means 12 L of  $SO_{2}$ is present per $10^{6} L gas$

The given temperature is 273 K (0 C) and pressure is 1 atm. At these conditions, 1 mol of gas would occupy,

$PV = nRT$

$(1 atm) (V) = (1 mol)(0.08206\frac{L.atm}{mol.K}) (273 K)$

V = 22.4 L

1 mol $SO_{2}$ occupies 22.4 L

Moles of $SO_{2}$ = $12 L *\frac{1 mol}{22.4 L} = 0.5357 mol SO_{2}$

Mass of  $SO_{2}$ =$0.5357 mol *\frac{64.06 g}{1 mol} = 34.32 g SO_{2} *\frac{10^{6} microgram}{1 g}$ =$3.432 *10^{7}$μg

Converting $10^{6} L to m^{3}$:

$10^{6} L *\frac{1 m^{3}}{1000 L}$ = $10^{3} m^{3}$

Calculating the concentration in μg/$m^{3}$:

$\frac{3.432 * 10^{7} microgram}{10^{3} L} = 3.432 * 10^{4} microgram/m^{3}$