Chapter 3
1. Describe how the bonding of Hydrogen and Oxygen result in a polar molecule and
and Hydrogen bonds.
Oxygen holds the electrons more tightly than does Hydrogen, creating an
unequal sharing of the electrons and charges. This results in charged areas in
the water molecule.
H bonds form between the positive Hydrogen area of one molecule to the
negative area of another.
2. Identify and describe four emergent properties of water that contribute to Earth’s
fitness for life.
3. During periods of hot weather, the dew point (humidity level) is often linked to our
level of comfort. Discuss why high dew points make us feel miserable.
high humidity prevents water from evaporating and cooling our bodies.
4. How can freezing of water split rocks?
water expands when it freezes, forcing the rocks to crack and break apart.
5. A certain biological molecule has the ability to accept Hydrogen ions. If this
molecule is added to water, what will happen to the pH? Explain.
the pH will increase or become more basic
fewer H+ ions are present which raises the pH value
6. Describe how a buffer works.
buffers can absorb or give up H+ ions keeping the pH constant.
7. In areas where the bedrock is granite, acid precipitation is often a major problem.
However, in areas where limestone is the bedrock, acid precipitation is not usually a
concern. Why?
limestone soils have calcium carbonate which serves as a buffer against the acid
rain. Granite soils don’t have a buffer against pH changes.
8. Uncle Paul doesn’t understand what all of the fuss is about with acid rain. After all, a
change in pH from 6.5 to 5.5 is only 1 unit, so how could it be harmful? Educate
Uncle Paul about why this pH is actually a problem.
pH is a log scale and a change of 1 pH unit is a 10X change in H+ ions.
9. The search for extraterrestrial life is often a search for the presence of water. Why?
the properties of water are conducive to life. If water is present, the changes of
life being present is much higher.