Pollutants from Burning Fuels · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

What else comes out of the flame

Science · Matter & Materials · ages 15-16
Name ______________________   Date ____________

  1. Why can a faulty gas heater be dangerous even when its flame looks normal?

    • It may release CO that you could detect by smell.
    • It may release CO only when the flame turns yellow.
    • It may release colourless, odourless carbon monoxide.

  2. Which pair is produced by complete combustion of a hydrocarbon in enough oxygen?

    • Carbon monoxide and water
    • Carbon dioxide and water
    • Carbon dioxide and hydrogen

  3. Sulfur dioxide released by burning sulfur-containing fuel can contribute to acid rain.

    Circle one:   True   False

  4. A supplier wants less sulfur dioxide to form when its fuel burns. Which change addresses that pollutant's source?

    • Reduce the fuel's sulfur content
    • Increase the air supply
    • Fit a catalytic converter to the exhaust

  5. Nitrogen is normally unreactive. Why can engines still make nitrogen oxides from air?

    • Nitrogen oxides enter ready-made with the air.
    • High temperatures let nitrogen and oxygen react.
    • The catalyst in the exhaust makes them from nitrogen.

  6. A power plant fits scrubbers to remove sulfur dioxide from flue gas. Which evaluation gives a benefit and a cost?

    • They cut SO2 and use no energy.
    • They cut CO but use energy and materials.
    • They cut SO2 but use energy and materials.

  7. A town has no nearby fuel-burning plants. A student says this rules out acid rain caused by fuel emissions. Why does that conclusion not follow?

    • Winds can carry the source gases from distant places.
    • Acid rain forms only when gases stay beside their source.
    • Rain carries acids only after source gases settle on local soil.

  8. Someone has headaches in a room with a fuel-burning heater and notices soot nearby. Carbon monoxide is suspected. What is the safest next action?

    • Open a window, then wait beside the heater.
    • Leave for fresh air, tell an adult and get emergency help.
    • Switch the heater off, then stay to check the flame.
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Answer key

For grown-ups. Fold this page away before handing over the rest.

What else comes out of the flame W1-mt_DDiyDBy6YW-s1

  1. It may release colourless, odourless carbon monoxide. · Faulty combustion can release carbon monoxide. Flame appearance cannot rule out this colourless, odourless poison.
  2. Carbon dioxide and water · Complete hydrocarbon combustion forms carbon dioxide from carbon and water from hydrogen.
  3. True · Sulfur burns to SO2. Dissolution and reactions in the atmosphere can form acids that fall in rain.
  4. Reduce the fuel's sulfur content · Less sulfur in the fuel means less sulfur is available to burn into sulfur dioxide.
  5. High temperatures let nitrogen and oxygen react. · Very high engine temperatures allow nitrogen and oxygen from air to react chemically.
  6. They cut SO2 but use energy and materials. · Scrubbers reduce SO2 emissions, but installation, maintenance and operation cost money and use energy.
  7. Winds can carry the source gases from distant places. · Winds can transport source gases away from fuel-burning sites. Even without a nearby plant, a town can receive acid rain linked to distant emissions.
  8. Leave for fresh air, tell an adult and get emergency help. · Suspected CO needs immediate safety action. Leave, tell an adult and get emergency help rather than testing the appliance.
Worksheet · LightMySky