Final answer:
The substance that is oxidized in the provided reaction is n-heptane (C₂H₁₆), which corresponds to option 1: C8H7ON. This is determined by assessing the changes in oxidation numbers where carbon is oxidized from an oxidation state of -3 to +4.
Step-by-step explanation:
To determine which substance is oxidized, we need to consider changes in oxidation numbers during a chemical reaction. Oxidation refers to the loss of electrons, which corresponds to an increase in oxidation state, while reduction involves a gain of electrons, corresponding to a decrease in oxidation state. Taking the provided reaction C₂H₁₆ + O₂ → 7CO₂ + 8H₂O, we can assign oxidation numbers to the carbon in n-heptane (C₂H₁₆) and oxygen in O₂.
In n-heptane, the oxidation number for carbon is -3, as in hydrocarbons, carbon has a lower oxidation number due to its bonding with hydrogen (which is assigned an oxidation number of +1). In the O₂ molecule, the oxidation number for oxygen is 0 since it is in its elemental state.
During the reaction, carbon is oxidized from -3 to +4 in CO₂, while oxygen is reduced to -2 in CO₂ and H₂O. Therefore, the substance that gets oxidized is the n-heptane (C₂H₁₆), corresponding to option 1: C8H7ON.