Final answer:
Without the model, one cannot accurately determine which chemical formula is represented by it. However, it is established how to indicate the number of formula units or molecules and moles in a balanced chemical equation.
Step-by-step explanation:
The question 'Which chemical formula is represented by the model?' can be answered if the model shows specific atoms and the bonds between them. Unfortunately, the model is not provided here to determine the correct formula. However, in typical chemistry notation:
- C₄H would represent a carbon chain with four carbon atoms and one hydrogen, which is unlikely as it suggests an incomplete or charged species.
- CH₄ is the formula for methane, a common and stable compound with one carbon atom and four hydrogen atoms.
- H₂O is the chemical formula for water, consisting of two hydrogen atoms bonded to one oxygen atom.
- CO₄ does not represent a commonly known stable molecule under standard conditions.
Looking at the provided reaction, 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, we can indicate the number of formula units or molecules: 2 formula units of C₂H₆, 7 formula units of O₂, 4 formula units of CO₂, and 6 formula units of H₂O. The number of moles corresponds to the coefficients in front of each chemical formula, representing the mole ratio in which reactants are consumed and products are formed.