Question

a) At standard conditions, the exhaust gas from a well-controlled coal-burning power plant contains 5 ppmv sulfur dioxide (SO2). At STP (0° C and 1 atm), determine the concentration of SO2 emitted on a µg/m3 basis.

b) What is the equilibrium concentration of a gas in water if its partial pressure is 0.1 atm and its Henry’s law constant is 0.1 mole/(liter.atm)?

Answer 1

Answer – a) We are given the 5 ppmv SO₂ and we need to calculate the concentration of SO₂ emitted on a µg /m³ basis.

We know,

mg/m³ = ppmv * M/0.08205*T

M = molecular weight of gas = 64.064 g/mol

mg/m³ = 5 ppmv *64.064 g.mol^-1/ 0.08205 * 273.15 K

       = 14.28 mg/m³

Now we know

1 mg = 1000 µg

So, 14.258 mg = ?

= 14280 µg/m³

b) We are given, partial pressure. P = 0.1 atm ,

Henry’s law constant = 0.1 mole/(liter.atm)

We know Henry’s law

C = Kh*P

    = 0.10 mol/L.atm * 0.10 atm

     = 0.01 mol/L

     = 0.01 M

So, the equilibrium concentration of a gas in water is 0.01 M.