Think about burning fuel in a car. That “combustion” reaction requires octane gas to burn in the presence of oxygen. The products are “lower energy” carbon dioxide and water. Which graph above best represents the general reaction? (left or right) Explain your answer.

Answer 1

To determine which direction the reaction graph should go (left or right), we need to consider the energy change during the combustion reaction of octane gas.

In the reaction of octane gas with oxygen, the reactants (octane gas and oxygen) have a certain amount of energy. During combustion, the reactants are converted into products (carbon dioxide and water) which have a lower energy than the reactants. This means that energy is released during the reaction.

Looking at the provided left and right graphs, we can observe that the left graph represents a reaction where the products have a lower energy than the reactants. This is consistent with the combustion of octane gas. On the other hand, the right graph does not show a decrease in energy from reactants to products.

Hence, the left graph best represents the general reaction of burning fuel in a car, where octane gas combusts in the presence of oxygen to form lower-energy products (carbon dioxide and water).