Question

is/are created when raw fuel evaporates into the atmosphere or when it does not burn at all in the combustion chamber and is exhausted out the tailpipe. a. oxygen molecules b. particulate matter c. oxides of nitrogen d. hydrocarbons

Explanation:

Hydrocarbons are organic compounds consisting of hydrogen and carbon. When raw fuel evaporates or doesn't burn completely (as in the described scenario), hydrocarbons are released. Oxygen molecules (\(O_2\)) are part of air and not directly related to un - burned fuel in this context. Particulate matter is solid or liquid particles, not the result of un - burned fuel evaporation or incomplete combustion in this sense. Oxides of nitrogen (\(NO_x\)) form from nitrogen in the air reacting at high temperatures, not from un - burned fuel.

Answer:

d. Hydrocarbons