As pure water approaches its freezing point, the density ...

[bobbie]

As pure water approaches its freezing point, the density decreases. Why does this happen?
  a. The water compresses into ice.
  b. The hydrogen bonds become rigid, allowing it to expand slightly.
  c. The hydrogen bonds break as the molecules compress.
  d. Ice takes up a smaller surface area than liquid water

Question 2

What is a hydrothermal vent? What process is involved in their making? Who is responsible for
  discovering these vents? What will be an ideal response?

[momo1250]

Answer to Question 1

ANS: B
When water molecules begin to freeze, the bond angles become wider. This allows the molecules to
precisely come together in hexagonal patterns. This particular lattice pattern causes water to expand as
it becomes a solid. The ice then becomes less dense than water. Information can be found in the
section Water Has Unusual Thermal Characteristics

Answer to Question 2

ANS:Answer
should include:
 Hydrothermal vents are hot springs that are found on ocean ridges. The water that is
released at these sites is super heated and enriched with metals. The acidity of the water
is often higher than normal sea water.
 These vents are created by the process of convection. It is thought that water seeps into
cracks and fissures of rocks where the seafloor is spreading. The super heated and
chemically active water then dissolves minerals and gases which escape through these
vents. Sometimes the minerals in these vents can turn the water different colors as it is
being released. An example of this would be black smoker hydrothermal vents.
 These vents are not limited to the ocean. They can be found in lakes and even on land.
Iceland has many of these hydrothermal vents because the mid-ocean ridge has risen
above ground. These vents are named fumaroles. The water immediately phase changes
once released and becomes steam.

[bobbie]

TY

[momo1250]

You're welcome