Video Transcript
Engineers record how much toxic nitrogen monoxide gas is released from the exhaust of
five different cars. They make a bar chart to show how much nitrogen monoxide gas is produced by each car
over the course of one day. Which car seems to have the most effective catalytic converter? (A) Car A, (B) car D, (C) car C, (D) car E, (E) car B.
Manufacturers have been building cars with catalytic converters for decades. Catalytic converters usually have a honeycomb structure and they are part of the car
exhaust system. They contain metals that speed up the decomposition of toxic gases into less harmful
products. The diagram describes the structure and function of a catalytic converter. It shows that catalytic converters are part of the car exhaust system. The diagram also indicates that toxic gas reactants turn into less harmful products
when they pass through a catalytic converter.
Nitrogen monoxide is a toxic gas that is generated by a car. It can damage the human respiratory system if it is inhaled. It may make people develop asthma and chronic obstructive pulmonary disorder as
well. Effective catalytic converters turn nitrogen monoxide into harmless elemental
nitrogen and oxygen products. Cars do not generate much nitrogen monoxide if they have an effective catalytic
converter. We can see from the bar chart that car C releases the least amount of nitrogen
monoxide. Car C therefore has the most effective catalytic converter. (C) is the correct answer.
