The products of the incomplete combustion of octane, C8H18, are carbon monoxide (CO) and water. The balanced chemical equation for this reaction is: 2 C8H18 + 17 O2 → 16 CO + 18 H2O
The Correct Answer and Explanation is:
To begin, the equation you’ve given for the incomplete combustion of octane (C8H18) is:
2 C8H18 + 17 O2 → 16 CO + 18 H2O
This represents a situation where octane reacts with oxygen but not enough oxygen is present to convert all the carbon atoms into carbon dioxide (CO2). Instead, carbon monoxide (CO) is produced as a result of incomplete combustion. Let’s break this down.
Explanation:
1. Combustion Reaction:
Combustion is a chemical reaction where a substance (in this case, octane) reacts with oxygen, releasing energy in the form of heat and light. In a complete combustion reaction, the products are carbon dioxide (CO2) and water (H2O). However, in incomplete combustion, not enough oxygen is available for all the carbon atoms to combine fully with oxygen. As a result, carbon monoxide (CO), a toxic gas, is produced along with water.
2. The Balanced Equation:
In the balanced equation:
- 2 C8H18 (liquid octane) reacts with 17 O2 (gaseous oxygen).
- This produces 16 CO (carbon monoxide) and 18 H2O (water).
The coefficients are balanced to ensure that the number of atoms on both sides of the equation is the same. For instance:
- On the left, we have 16 carbon atoms from 2 molecules of C8H18.
- On the right, we also have 16 carbon atoms from the 16 CO molecules.
- Similarly, for hydrogen, oxygen, and other elements, the equation maintains balance.
3. Why Incomplete Combustion Happens:
Incomplete combustion typically occurs when there is insufficient oxygen, either due to low oxygen supply or the system’s design (e.g., an engine not getting enough air). Under these conditions, carbon monoxide (CO), which is dangerous to health, is produced instead of carbon dioxide (CO2). In engines, such incomplete combustion can also lead to the production of soot (unburnt carbon particles).
4. Risks of Carbon Monoxide:
Carbon monoxide is a colorless, odorless gas that can be harmful when inhaled, as it reduces the oxygen-carrying capacity of blood. This is why ensuring complete combustion is important in processes like internal combustion engines.
In summary, the incomplete combustion of octane results in carbon monoxide and water due to the limited availability of oxygen. The balanced equation ensures that the conservation of mass is maintained, and the stoichiometry can be used for further calculations such as determining the amount of CO produced under specific conditions.
