Octane (c8h18) reacts with oxygen (o2) to form carbon dioxide (co2) and water (h2o). when the equation below is balanced, the coefficient of octane is: c8h18 + o2 → co2 + h2o

2 C₈H₁₈ + 25 O₂ → 16 CO₂ + 18 H₂O

Solution:

Step 1: Write down the unbalanced chemical equation,

C₈H₁₈ + O₂ → CO₂ + H₂O

Step 2: Balance the Carbon atoms as,

As there are 8 carbon atoms in octane, therefore we will multiply CO₂ by 8 in order to balance it i. e.

C₈H₁₈ + O₂ → 8 CO₂ + H₂O

Step 3: Balance the Hydrogen atoms;

C₈H₁₈ + O₂ → 8 CO₂ + 9 H₂O

Step 4: Balance the Oxygen atoms as,

C₈H₁₈ + 12.5 O₂ → 8 CO₂ + 9 H₂O

Step 5: Multiply last equation by 2 in order to remove fractions as,

2 C₈H₁₈ + 25 O₂ → 16 CO₂ + 18 H₂O