Explain how nitrogen monoxide (NO\text{NO}NO) is formed in internal combustion engines.
State one environmental or health hazard associated with the emission of oxides of nitrogen.
Exhaust gas treatment systems utilize ammonia, NH3\text{NH}_3NH3, to reduce emissions of nitrogen monoxide, NO\text{NO}NO. In the presence of a catalyst, ammonia reacts with nitrogen monoxide to form nitrogen and water.
Rhodium in catalytic converters acts as a heterogeneous catalyst to convert harmful pollutants. State the meaning of the term heterogeneous catalyst.
Carbon monoxide (CO\text{CO}CO) is another pollutant formed in car engines during fuel combustion. Explain why carbon monoxide is formed instead of carbon dioxide.