Xinyi saw a poster showing carbon monoxide and asked John, “Where does it come from?” Which is a common source of carbon monoxide in urban areas?

While working on their smog awareness project, Xinyi explains the role of unburnt hydrocarbons and ozone. Which condition is necessary for photochemical smog to form?

A region experienced unusually high temperatures and smog. Satellite data showed a spike in atmospheric ozone levels. Which combination of gases and conditions most likely caused this?

Trying to neutralise the sulfur dioxide, Xinyi grabbed a beaker of calcium hydroxide solution. Which balanced equation shows what happened next?

John then decided to introduce sulfur dioxide into the jar 'for fun'. Xinyi immediately started coughing. Which property of sulfur dioxide explains this reaction?

A student sets up two sealed flasks: one with oxygen and methane, and one with oxygen and nitrogen dioxide. Both are exposed to UV light. Which flask would most likely contribute to the formation of ground-level ozone?