Reactivity 1.3—Energy from fuels

What is the general equation for the complete combustion of a hydrocarbon?

• CxHy + CO2 → H2 + O2

• CxHy + O2 → CO2 + H2O

• CxHy + H2O → CO + O2

• CxHy + N2 → CO2 + H2O

Write the balanced equation for the combustion of ethanol (C2H5OH).

• C2H5OH + O2 -> C2H4 + H2O

• C2H5OH + 3 O2 -> 2 CO2 + 3 H2O

• C2H5OH + 4 O2 -> 3 CO2 + 4 H2O

• C2H5OH + 2 O2 -> CO2 + 2 H2O

What are the products of complete combustion of methane (CH4)?

• Carbon monoxide (CO) and hydrogen (H2)

• Carbon dioxide (CO2) and water (H2O)

• Nitrogen oxides (NOx) and sulfur dioxide (SO2)

• Methane (CH4) and oxygen (O2)

Explain why high activation energy is considered beneficial for fuels.

• High activation energy prevents accidental ignition and ensures efficient combustion.

• Low activation energy is safer for storage and transport.

• High activation energy increases the energy output of fuels.

• High activation energy leads to faster combustion rates.

Identify the oxidizing agent in the combustion of propane (C3H8).

• Oxygen (O2)

• Water (H2O)

• Carbon dioxide (CO2)

• Propane (C3H8)

What is the role of a reducing agent in a combustion reaction?

• The reducing agent acts as a catalyst to speed up the reaction.

• The reducing agent donates electrons and facilitates the combustion process by reducing the oxidizing agent.

• The reducing agent absorbs heat and prevents combustion.

• The reducing agent increases the amount of oxygen in the reaction.

Write the equation for the incomplete combustion of butane (C4H10).

• C4H10 + 5 O2 -> 4 CO2 + 5 H2O

• 2 C4H10 + 9 O2 -> 8 CO + 10 H2O

• 2 C4H10 + 8 O2 -> 6 CO + 10 H2O

• C4H10 + 3 O2 -> 2 CO + 4 H2O

What are the potential health risks associated with carbon monoxide production during incomplete combustion?

• Health risks include headaches, dizziness, confusion, loss of consciousness, and potential death due to reduced oxygen delivery in the body.

• Enhanced physical endurance and strength

• Improved cognitive function and memory

• Increased appetite and weight gain

Describe the observable changes when methane is burned in a limited supply of oxygen.

• Burning methane in limited oxygen produces a yellow flame, smoke, and carbon monoxide.

• Methane burning in limited oxygen results in a clean flame and carbon dioxide.

• Combustion of methane in excess oxygen creates soot and nitrogen gas.

• Burning methane produces a blue flame and water vapor.

What is the difference between complete and incomplete combustion?

• Complete combustion produces only carbon monoxide; incomplete combustion produces carbon dioxide and water.

• Complete combustion results in soot and ash; incomplete combustion results in only carbon dioxide.

• Complete combustion produces carbon dioxide and water; incomplete combustion produces carbon monoxide and soot.

• Complete combustion occurs in the absence of oxygen; incomplete combustion occurs in the presence of oxygen.