Worksheet: Incomplete Combustion of Hydrocarbons

In this worksheet, we will practice describing the incomplete combustion of hydrocarbons by writing, balancing, and interpreting chemical equations.


Which of the following combustion reactions is incomplete?

  • AC+OCO22
  • BCH+OC+2HO422
  • CCH+3O2CO+2HO24222
  • D2CH+5O4CO+2HO22222
  • E2CH+7O4CO+6HO26222


For a fuel to undergo incomplete combustion, which of the following must be present in insufficient quantities?

  • AFuel
  • BLight
  • CHeat
  • DWater
  • EOxygen


Which toxic, colorless and odorless gas may be produced by the incomplete combustion of a hydrocarbon?

  • ASulfur dioxide
  • BHydrogen peroxide
  • CCarbon dioxide
  • DCarbon monoxide
  • ESteam


Which of the following compounds is least likely to be produced during the incomplete combustion of a hydrocarbon?

  • AC
  • BCO2
  • CHO2
  • DCO
  • EHO22


Why is carbon monoxide a poisonous gas?

  • AIt irritates mucous membranes in the eyes.
  • BIt causes suffocation.
  • CIt irritates the respiratory tract.
  • DIt inhibits the ability of the blood to carry oxygen.
  • EIt causes blindness.


Which three numbers in the correct order balance the following incomplete combustion reaction? CH+OCO+CO+HO38222𝑥𝑦𝑧

  • A2, 1, 2
  • B4, 4, 2
  • C2, 2, 4
  • D4, 2, 4
  • E2, 2, 2


Hexane was burnt in a crucible and incomplete combustion occurred. Which equation represents incomplete combustion?

  • ACH+3O6CO+6H61222
  • BCH+6O6CO+6H6122
  • CCH+12O6CO+6HO6122
  • DCH+9O6CO+6HO612222
  • ECH+6O6CO+6HO61222


Which of the following word equations represents the incomplete combustion of methane?

  • AMethane + oxygen → carbon monoxide + hydrogen
  • BMethane + oxygen → carbon monoxide + water
  • CMethane + oxygen → carbon dioxide + hydrogen
  • DMethane + oxygen → carbon dioxide + water
  • EMethane + water → carbon dioxide + hydrogen


Which of the following can only be produced from an incomplete combustion reaction?

  • ASmaller hydrocarbons
  • BMethane
  • CHydrogen
  • DCarbon
  • ECarbon dioxide


Which of the following observations is a difference between a complete and an incomplete combustion reaction?

  • AA dirty flame is observed.
  • BMore energy is produced.
  • CSoot is formed.
  • DA toxic gas is formed.
  • EBlack smoke is formed.


Which poisonous gas, produced by incomplete combustion, is monitored by gas detectors fitted in some homes?

  • AMethane
  • BOxygen
  • CWater vapor
  • DCarbon dioxide
  • ECarbon monoxide


Which of the following statements is true?

  • AIncomplete combustion produces a high amount of energy.
  • BIncomplete combustion occurs when a high amount of O2 is available.
  • CIncomplete combustion is the complete oxidation of fuel.
  • DIncomplete combustion produces carbon dioxide and water as the only products.
  • EIncomplete combustion is the partial oxidation of fuel.


What are the main products formed during incomplete combustion?

  • ACO+HO+C22 (soot)
  • BHO+CO2
  • CCO+C (soot)
  • DCO+HO22
  • ECO+HO+C2 (soot)


What is the environmental impact of incomplete combustion reactions?

  • AGlobal warming from carbon and smoke
  • BAir pollution from carbon dioxide and water
  • CAir pollution from carbon dioxide and smoke
  • DAir pollution from carbon monoxide and smoke
  • EGlobal warming from carbon dioxide


Which of the following statements is false?

  • AIncomplete combustion produces CO+HO+C2 (soot) as byproducts.
  • BIncomplete combustion produces a poisonous gas.
  • CIncomplete combustion is the complete oxidation of fuel.
  • DIncomplete combustion is the partial oxidation of fuel.
  • EIncomplete combustion occurs when there is not enough amount of O2 available.


Fill in the blank: Incomplete combustion of hydrocarbons occurs if not enough is present.

  • Ahydrogen
  • Bcarbon monoxide
  • Chydrogen peroxide
  • Dcarbon dioxide
  • Eoxygen


During incomplete combustion of a hydrocarbon the carbon atoms react with oxygen to produce instead of .

  • Acarbon monoxide, carbon dioxide
  • Bcarbon monoxide, water
  • Ccarboxylic acid, carbon monoxide
  • Dcarbon dioxide, carbon monoxide
  • Ecarbon dioxide, water


Fill in the blank: In incomplete combustion, a flame is usually produced, while in complete combustion, a flame is produced.

  • Ablue, orange
  • Bblack, blue
  • Corange, yellow
  • Dred, yellow
  • Eyellow, blue


Methane is a simple hydrocarbon. Complete the following word equation to show what happens when methane is incompletely combusted. Methane++

  • Aoxygen, carboxylic acid, water
  • Boxygen, carbon, hydrogen
  • Coxygen, carbon monoxide, carbon dioxide
  • Doxygen, carbon monoxide, water
  • Eoxygen, carbon dioxide, water

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