Answer:
1 C₂H₆O
Step-by-step explanation:
The given equation:
C₂H₆O + 3 O₂ ---> 2 CO₂ + 3 H₂O
Reactants: 2 carbon, 6 hydrogen, 7 oxygen
Products: 2 carbon, 6 hydrogen, 7 oxygen
As you can see, the amount of each element on both sides is identical. Therefore, the reaction is already balanced. This means that the coefficient in front of C₂H₆O is 1. When writing the equation, writing the one is insignificant and usually left out.