Cell Compounds:
B1. Describe how the polarity of the water molecule results in hydrogen bonding:
Water is classified as a polar molecule because of the unequal sharing of electrons
between the hydrogen and oxygen ions. Because the oxygen ions are larger, they create a
greater pull on the orbiting electrons. This causes the electrons to orbit the oxygen ions
more frequently, granting the oxygen with a slightly negative charge. This leaves the
hydrogen ions with a slightly positive charge. Because of these charges, oxygen ions
from one water molecule and the hydrogen ions from another water molecule are
attracted together. This bond between water molecules is called a hydrogen bond. It is a
weak bond, but is very important in giving water some specific, unique characteristics.
Water is attracted to itself by cohesion and by adhesion to other molecules. This is why
water creates a meniscus in a beaker- it is attracted to the plastic material of the beaker
and this pulls the water up on the
sides of the test tubes.
B2. Describe the role of water as a solvent, temperature regulator, and lubricant:
Water acts as a great solvent, temperature regulator, and lubricant. It is a chemical, and
very important for it's chemical properties. Water dissolves inorganic, polar materials
(like dissolves like.) Water is used to regulate temperature in many places, including our
bodies. Because of the thickness of water due to hydrogen bonding, water has a high heat
capacity. This means it requires a lot of energy in order for the temperature of water to
raise. This allows us to maintain a very precise body temperature, even with different
temperatures around us. This is vital because the proteins in our body will only function
in a narrow temperature range. Because water molecules have a fixed space in between
themselves when they freeze, it makes the density of frozen water less than the density of
liquid water.
Water is also a lubricant.
In our eyes (tears)
in our joints (reduces friction) also around our lungs, heart
as saliva (swallowing),
in our skull (as a protective fluid) may result in a concussion
It is also used in our joints, our digestion, our organs, and even our
Another quality of water is it's surface tension. Because of hydrogen bonding, water is
pulled together to create the smallest surface area possible.
Water is a lubricant.