In the balanced chemical reaction for aerobic respiration, glucose (C₆H₁₂O₆) is converted into carbon dioxide (CO₂) and water (H₂O) with the consumption of oxygen (O₂). The balanced equation is:
\[ C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O \]
In this equation, the missing coefficient for O₂ is 6.