Question

Q2.
The SO2 content of a sample stack gas measured at 850°C and 2 atm pressure is 9 ppm. determine the SO2 concentration in micrograms per cubic meter​

Answer 1

Answer:

Problem :

An SO2 concentration is given as 830mg/m3 at 25°C and 1 atm. Express this concentration in parts per million (ppm).

Solution :

Step 1

Concentration of SO2 is 830 mg/m3

AT STP conditions (25°C and 1 atm), one mole of gas occupies 24.5 L

(V=nRT/P).

Molecular Weight of SO2 is 64g/mol

Step 2

ppm =

concentration(10 mg/m3) x 24.5 L/mol

molecular weight(g/mol) x 1000 (mL/m3*g)

Step 3

ppm =

830 (mg/m3) x 24.5 L/mol

64 (g/1 mol SO2) x 1000 (mL/m3*g)

= 0.32 ppm

Exercise: Carbon Monoxide concentration at 90°C and 6 atm is 90 mg/m3. Express this concentration in ppm.

(0.016 ppm)

Problem :

The exhaust from a 1981 Honda contains 1.5% by volume of carbon monoxide. Compute the concentration of CO in milligrams/m3 at 25°C and 1 atm of pressure.

Solution :

Step 1

1 percent by volume = 104 ppm.

1.5 percent by volume = 1.5*104 ppm.

Molecular Weight of CO is 28 g/mol

Step 2

concentration (mg/m3) =

ppm x molecular weight(g/mol) x 1000 (mg*L/m3*g)

24.5 (L/mol)

Step 3

concentration (mg/m3) =

1.5 x 104 ppm x 28(g/mol) x 1000 (mg*L/m3*g)

24.5 (L/mol)

= 1.71 x 107 ug/m3 = 1.71 x 104 mg/m3

Exercise: An exhaust gas containing 3.2 percent by volume SO2 is released at 25°C and 1 atm. Compute the concentration in mg/m3.

(8.36 x 104 mg/m3)