G3 Properties of Fuel Gases 2

Question 1

What is the ignition temperature of natural gas?

Accepted Answer

593°C (1,100°F)

Answer

250°C (482°F)

Answer

400°C (752°F)

Answer

815°C (1,500°F)

Question 2

How does propane's specific gravity differ from natural gas?

Accepted Answer

Propane is heavier than air (SG ~1.52); natural gas is lighter (SG ~0.60)

Answer

Propane is lighter; natural gas is heavier

Answer

Both have the same specific gravity

Answer

Natural gas is heavier than propane

Question 3

What is propane's heating value compared to natural gas?

Accepted Answer

Propane has approximately 2.5 times the value per cubic foot

Answer

Propane has lower heating value

Answer

Both are identical

Answer

Natural gas has twice propane's value

Question 4

What is the flammable range of propane in air?

Accepted Answer

2.1% to 9.5%

Answer

5% to 15%

Answer

1% to 5%

Answer

10% to 20%

Question 5

What determines flame speed and why does it matter?

Accepted Answer

Rate a flame front travels through gas-air mixture; affects burner design

Answer

Flame colour; affects aesthetics

Answer

Time to maximum temperature; affects pipe sizing

Answer

Rate of gas flow; affects noise

Question 6

What is the chemical equation for complete methane combustion?

Accepted Answer

CH4 + 2O2 → CO2 + 2H2O

Answer

CH4 + O2 → CO + H2O

Answer

CH4 + 3O2 → CO2 + 3H2O

Answer

2CH4 + O2 → 2CO2 + H2O