Final answer:
The hot exhaust gases from an internal combustion engine mainly consist of nitrogen oxides and carbon monoxide, which are converted into less harmful substances by the catalytic converter.
Step-by-step explanation:
The hot exhaust gases of an internal combustion engine are a complex mixture of several substances. The key components in the gas emissions from a gasoline-powered vehicle include nitrogen oxides (NOx), which are formed when nitrogen reacts with oxygen under the high temperatures in an engine, and carbon monoxide (CO), which results from the incomplete combustion of hydrocarbons. In addition to these, other materials such as volatile hydrocarbons and particulate matter are also released. These substances can be harmful to the environment and human health. Thankfully, the presence of a catalytic converter helps in converting these pollutants into less harmful products such as carbon dioxide (CO₂) and water vapor (H₂O).