Isooctane, C₈H₁₈, is the component of gasoline from which the term octane rating derives. (a) Write a balanced equation for the combustion of isooctane(l) with O₂ to yield CO₂(g) and H₂O(l)

Verified step by step guidance

1. Start by writing the unbalanced chemical equation for the combustion of isooctane: C_8H_{18}(l) + O_2(g) \rightarrow CO_2(g) + H_2O(l)
2. Balance the carbon atoms first. Isooctane has 8 carbon atoms, so you need 8 CO_2 molecules: C_8H_{18}(l) + O_2(g) \rightarrow 8CO_2(g) + H_2O(l)
3. Next, balance the hydrogen atoms. Isooctane has 18 hydrogen atoms, so you need 9 H_2O molecules: C_8H_{18}(l) + O_2(g) \rightarrow 8CO_2(g) + 9H_2O(l)
4. Now, balance the oxygen atoms. There are 8 CO_2 molecules and 9 H_2O molecules, which require a total of 25 oxygen atoms. Therefore, you need \frac{25}{2} O_2 molecules: C_8H_{18}(l) + \frac{25}{2}O_2(g) \rightarrow 8CO_2(g) + 9H_2O(l)
5. To eliminate the fraction, multiply the entire equation by 2 to get whole numbers: 2C_8H_{18}(l) + 25O_2(g) \rightarrow 16CO_2(g) + 18H_2O(l)

Key Concepts

Combustion Reaction

A combustion reaction is a chemical process in which a substance reacts rapidly with oxygen, producing heat and light. In the case of hydrocarbons like isooctane, the products of complete combustion are carbon dioxide (CO2) and water (H2O). Understanding this type of reaction is essential for writing balanced equations and predicting the products formed.

Balancing Chemical Equations

Balancing chemical equations involves ensuring that the number of atoms of each element is the same on both sides of the equation. This is based on the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. Proper balancing is crucial for accurately representing the stoichiometry of the reaction.

Stoichiometry

Stoichiometry is the quantitative relationship between the reactants and products in a chemical reaction. It allows chemists to calculate the amounts of substances consumed and produced, based on the balanced equation. In the context of combustion, stoichiometry helps determine how much oxygen is needed to completely combust a given amount of isooctane.