Qrtr 4 final

The Learning Goal for this assignment is:
Take note over the following chapter. Use the Headings provided to organize your notes. Define and number all highlighted vocabulary (total 22 ) as well
as summarize and take notes over the sections. You may add pictures where needed. The pictures should be an appropriate size. Use Arial 12 for all
text. This document should be 2 pages and should be saved as a pdf before you submit it into Angel.
Chapter 15 Water and Aqueous Systems
Pages 488 - 507
15.1 Water and Its Properties
Water in the Liquid State
Water is essential for all life on earth. It is most abundant in the oceans and underground as liquid
water, in the poles as solid ice, and in the air as water vapor. Water as a molecule is polar so this
affects its solubility. In addition to being a great solvent, the hydrogen bond of water gives it unique
characteristics like high surface tension and high boiling point. These characteristics are so important
because of the role water plays in life on earth. Surface tension 1, or the inward force the tends to
minimize the surface area of a liquid, also explains why water will pool and bead when spilled on the
floor or on plants when it rains. A surfactant 2 will interfere with the hydrogen bonds in water to reduce
surface tension. Surfactants are used in soaps and cleaning agents to wet the surface more readily
and to emulsify oily substances. Low vapor pressure is also due to hydrogen bonds since the bonds
hold water molecules together. These bonds are not readily broken so the tendency of the molecules
to escape is low and at a lower rate than other liquids. Lastly, a high boiling point is due to the
aforementioned hydrogen bond. It takes a lot more energy to disrupt the hydrogen bonds in water.
Water in the Solid State
Water in the solid state also possesses unique traits. Ice cubes float in beverages and other water
based liquids because solid water has a lower density than liquid water. This is a unique
characteristic of water because when liquids cool, they contract and slowly build up
density until they are solid. The solid ends up being denser than the liquid which is
not true of ice and water. This is due to the fact that the structure of ice is a regular
open framework of water molecules in a hexagonal arrangement. The fact that ice
floats on top of water is important for organisms because ice on bodies of water acts
as an insulator and keeps all the water from freezing solid. The fact that liquid water
remains in the places like the north and south poles ensures that aquatic organisms stay alive in the
winter months.
15.2 Homogeneous Aqueous Systems
Solutions
Water is such a great solvent that it is near impossible to find pure water in nature. An aqueous
solution 3 is defined as water that contains dissolved substances. A dissolving medium like water is
called a solvent 4 . The substance being dissolved is called the solute 5 . Solutions are homogeneous
mixtures which basically means any given sample will contain the same amount of solvent and solute.
It is the same (homo) throughout. Like dissolves like when talking about solutions. Polar compounds
will dissolve polar compounds, and vice versa. However, non-polar compounds like gasoline and oil
are not easily dissolved in polar compounds like water. The process of solvation 6 is where the
positive and negative ions become surrounded by solvent molecules. Some ionic compounds have
ionic attractions stronger than the attraction exerted by water and are therefore nearly insoluble.