Consider the unbalanced equation for the combustion of hexane: C6H14(g) + O2(g) → CO2(g) + H2O(g). Balance the equation and determine how many moles of O2 are required to react completely with 7.2 moles of C6H14.

Verified step by step guidance

1. Write the unbalanced chemical equation: \( \text{C}_6\text{H}_{14}(g) + \text{O}_2(g) \rightarrow \text{CO}_2(g) + \text{H}_2\text{O}(g) \).
2. Balance the carbon atoms by ensuring the number of \( \text{CO}_2 \) molecules equals the number of carbon atoms in hexane: \( \text{C}_6\text{H}_{14}(g) + \text{O}_2(g) \rightarrow 6\text{CO}_2(g) + \text{H}_2\text{O}(g) \).
3. Balance the hydrogen atoms by ensuring the number of \( \text{H}_2\text{O} \) molecules equals half the number of hydrogen atoms in hexane: \( \text{C}_6\text{H}_{14}(g) + \text{O}_2(g) \rightarrow 6\text{CO}_2(g) + 7\text{H}_2\text{O}(g) \).
4. Balance the oxygen atoms by adjusting the \( \text{O}_2 \) molecules: \( \text{C}_6\text{H}_{14}(g) + 19\text{O}_2(g) \rightarrow 6\text{CO}_2(g) + 7\text{H}_2\text{O}(g) \).
5. Use the balanced equation to determine the moles of \( \text{O}_2 \) needed for 7.2 moles of \( \text{C}_6\text{H}_{14} \) by multiplying the moles of \( \text{C}_6\text{H}_{14} \) by the ratio of \( \text{O}_2 \) to \( \text{C}_6\text{H}_{14} \) from the balanced equation.

Key Concepts

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 achieved by adjusting the coefficients in front of the chemical formulas. For combustion reactions, it is essential to balance the carbon, hydrogen, and oxygen atoms to reflect the conservation of mass.

Stoichiometry

Stoichiometry is the quantitative relationship between reactants and products in a chemical reaction. It allows us to calculate the amount of one substance needed to react with a given amount of another. In this case, stoichiometry will help determine how many moles of O2 are required for the complete combustion of 7.2 moles of C6H14 based on the balanced equation.

Combustion Reactions

Combustion reactions are exothermic reactions that typically involve a hydrocarbon reacting with oxygen to produce carbon dioxide and water. In the case of hexane, the combustion reaction releases energy and is characterized by the formation of CO2 and H2O. Understanding the products and the general form of combustion reactions is crucial for balancing and calculating reactant requirements.