Section 4.5: Chemistry Journal
Section 4.5 Questions, page 171
1. Some mercury is released by the combustion of fossil fuels such as coal and is carried to the
Arctic by wind.
2. The bromide ion is less reactive than the bromine atom because its outer orbit of electrons is
complete. The atom, on the other hand is reactive because it is one electron short of having a
complete outer orbit.
3. Carbon compounds that contain mercury are a greater environmental concern than elemental
mercury because they can dissolve more readily in the fatty tissue of organisms and accumulate
in the food chain.
4. We can predict that mercury is unreactive because it is close to the bottom of the activity
series. Therefore, mercury can persist for a long time without reacting.
5. Mercury is a liquid at room temperature. Like any liquid, it evaporates into the air or becomes
a gas even at very low temperatures before it can be burned and destroyed at high temperatures.
6. Bottenheim uncovered clues to explain the disappearance of mercury when he examined data
collected by an atmospheric scientist studying the levels of bromine in the atmosphere.
7. Organisms at the top of Arctic food chains often have the highest levels of mercury because
they eat micro-organisms that have already absorbed mercury and converted it to organic
mercury compounds that readily accumulate in the fat tissue of larger organisms.
8. Less ice means that more ocean is exposed. More bromide ions would be available to react
with mercury in the atmosphere. As a result, mercury would disappear faster from the
atmosphere.
9. Answers may vary. Students’ answers will likely include fundamental research into the fate of
industrial pollutants, which is critical to understanding how these pollutants impact fragile
ecosystems like those in the Arctic.
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Chapter 4: The Effects of Chemical Reactions
4.5-1