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The Learning Goal for this assignment is: The students will learn how interactions<br />
between water molecules account for the unique properties of water and how aqueous<br />
solutions form.<br />
Take note over the following chapter. Use the Headings provided to organize your notes. Define and number all highlighted vocabulary (total 22<br />
) as well<br />
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<br />
text. This document should be 2 pages and should be saved as a pdf before you submit it into Angel.<br />
Chapter 15 Water and Aqueous Systems<br />
Pages 488 - 507<br />
15.1 Water and Its Properties<br />
Water in the Liquid State<br />
Water is a simple molecule consisting of one oxygen and two hydrogen atoms. The bond between<br />
oxygen and hydrogen is highly polar; the oxygen atom to have a partial negative charge and the<br />
hydrogen atoms to have partial positive charges. The water molecule as whole is polar and its polarity<br />
gives the molecule is bent shape. Polar molecules are attracted to one another by dipole interactions<br />
which causes hydrogen bonds. High surface tension, low vapor pressure, and high boiling point are<br />
factors that result from hydrogen bonding. Surface tension 1 is the inward force, or pull, that tends to<br />
minimize surface area of a liquid. That is why the surface of water is not flat and water droplets on<br />
leaves look spherical. The surface tension of water can be reduced by a surfactant2 which is, any<br />
substance that interferes with hydrogen bonding between water molecules. Vapor pressure results<br />
from molecules escaping from the surface of the liquid and entering the vapor phase. The tendency of<br />
water molecules to break is low because of the hydrogen bonds. Water has a high boiling point<br />
because it takes more heat to disrupt attraction between water molecules.<br />
Solutions<br />
Water is usually found as an aqueous solution 3 which is, water that contains dissolved substances<br />
like minerals and gases. The solvent4 is the the dissolving medium in a solution while the solute5 is<br />
the dissolved particles in a solution. Solvents and solutes may be gases liquids or solids. Solutions<br />
are homogeneous mixtures, meaning both the solute and the solvent pass through the filter. Ionic<br />
compounds and polar covalent compounds are substances that dissolve most readily in water. The<br />
solution process occurs when individual solute ions break away from the crystal and the negatively<br />
and positively charged ions become surrounded by solvent molecules and the ionic crystal dissolves.<br />
The process by which the positive and negative ions of an ionic solid become surrounded by solvent<br />
molecules is called solvation 6 . Some ionic compounds are insoluble because the attractions among<br />
the ions are stronger than the attractions exerted by water. The expression “like dissolves like”<br />
explaims why polar and ionic compounds dissolve each other while non-polar and non-polar<br />
compounds dissolve each other<br />
130<br />
Electrolytes and Nonelectrolytes<br />
An electrolyte 7 is a compound that conducts an electric current when it is in aqueous solution or in the<br />
molten state. All ionic compounds are electrolytes because they dissociate into ions. An electrolyte<br />
can conduct electricity if ions are present in the solution. They carry electrical charge from one<br />
electrode to the other, completing the electrical circuit. A nonelectrolyte 8 is a compound that does not
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