Oxygen percentage (by weight) in atmospheric air is_________________?

Related Mcqs:

1. Furnace oil consumption in a furnace for a given duty employing preheated combination air (at 300°) may be reduced by about ______________ percent as compared to the use of atmospheric combustion air?

   A. 5
   B. 10
   C. 20
   D. 35

2. Pure carbon is completely burnt in oxygen. The flue gas analysis is 70%CO2, 20%CO and 10%O2. The percent excess oxygen used is __________________?

   A. 20
   B. 12.5
   C. 0
   D. 10

3. Tolerable concentration of toxic carbon monoxide in atmospheric air is about ______________ ppm?

   A. 50
   B. 1000
   C. 5000
   D. 10000

4. Volumetric ratio of N2 to O2 in dry atmospheric air is ______________?

   A. 0.21
   B. 3.76
   C. 4.76
   D. 0.79

5. The maximum adiabatic flame temperature in air is _____________ the maximum flame temperature in pure oxygen?

   A. Lower than
   B. Higher than
   C. Same as
   D. Not related to

6. The maximum adiabatic flame temperature in air as compared to that in pure oxygen is_______________?

   A. Much lower
   B. Much higher
   C. Same
   D. Either lower or higher, depends on the type of fuel

7. The ratio of maximum adiabatic flame temperature in air to that in pure oxygen is always___________________?

   A. 1
   B. < 1
   C. > 1
   D. Unpredictable

8. Oxygen content in a flue gas was found to be 4%. It implies that excess air used for combustion was around ______________ percent?

   A. 4
   B. 96
   C. 20
   D. 40

9. Gasification of the solid fuel converts its organic part into combustible by interaction with air/oxygen and steam so as to obtain a secondary gaseous fuel of high calorific value having no ash. Gasification reactions are normally carried out at about _____________ °C?

   A. 400-500
   B. 900-1000
   C. 1400-1500
   D. 1700-1800

10. Ignition temperature of a fuel in air is ______________ that in pure oxygen?

    A. More than
    B. Less than
    C. Equal to
    D. Either more or less; depends on the type of fuel