Write the balanced chemical equation for the complete combustion of hexane (l).
The correct answer and explanation is:
Balanced Chemical Equation for the Complete Combustion of Hexane (l):
2 C₆H₁₄ (l) + 19 O₂ (g) → 12 CO₂ (g) + 14 H₂O (g)
Explanation (300 words):
Complete combustion is a chemical reaction where a hydrocarbon reacts fully with oxygen to produce carbon dioxide and water. In this case, the hydrocarbon is hexane, which has the chemical formula C₆H₁₄. Hexane is a liquid alkane consisting of six carbon atoms and fourteen hydrogen atoms. The goal of complete combustion is to ensure all carbon becomes carbon dioxide and all hydrogen becomes water.
To balance the equation, begin by writing the unbalanced form:
C₆H₁₄ + O₂ → CO₂ + H₂O
Start with carbon atoms. Hexane has 6 carbon atoms, so the equation must produce 6 CO₂ molecules:
C₆H₁₄ + O₂ → 6 CO₂ + H₂O
Next, balance the hydrogen atoms. Hexane has 14 hydrogen atoms, so the equation must produce 7 H₂O molecules:
C₆H₁₄ + O₂ → 6 CO₂ + 7 H₂O
Now count the total oxygen atoms on the right side. There are 6 CO₂ (6×2 = 12 oxygen atoms) and 7 H₂O (7×1 = 7 oxygen atoms), giving a total of 19 oxygen atoms. Since each O₂ molecule contains 2 oxygen atoms, 19 ÷ 2 = 9.5 O₂ molecules are required.
To eliminate the fraction, multiply the entire equation by 2:
2 C₆H₁₄ + 19 O₂ → 12 CO₂ + 14 H₂O
This is now the balanced equation for the complete combustion of liquid hexane. This reaction is exothermic, releasing a large amount of heat, which makes hexane a useful fuel. Complete combustion requires sufficient oxygen; otherwise, incomplete combustion occurs, producing carbon monoxide or soot, which are hazardous byproducts.
