Chapter+III+Review+Page

=Water and the Fitness of the Environment= __Water's Polarity__ The atoms in a water molecule form a polar covalent bond (the Oxygen part has the positive charge and the Hydrogen part has the negative charge.) Water is polar because the opposite sides of the molecule have opposite charges.

__Cohesion__- The Hydrogen bonds that hold a substance together. __Adhesion__- The clinging of one substance to another. __Surface Tension__- Measure of how difficult it is to stretch or break the surface of a liquid. __Heat and Temperature__- all atoms have kinetic energy since they are always moving around. Heat is the measurement of total kinetic energy in a body. A calorie is the amount of heat energy it takes to raise the temperature of one gram of water one Celsius degree. Water has a **high specific heat**. Specific heat is the amount of heat that must be absorbed or lost for one gram of a substance to change its temperature by one Celsius degree. An example of this is how you can burn yourself on the pot that contains the water when the water inside is still just warm. Going along with high specific heat is the **heat of evaporation,** which is how much heat is absorbed in order for 1g of liquid to change to a gas. Because of the heat of evaporation, **evaporative cooling** happens. Evaporative cooling is when the "hottest" molecules evaporate and leave the "cooler" molecules behind with less kinetic energy. Ice does not float because of the hydrogen bonds making it less dense than water. __Solutions__ In an **aqueous solutions** water is the is **solvent** while the **solute** is the substance that dissolves.

__pH__ The dissociation of substances with H increases the H+ concentration which affects pH. pH is the measure of concentration of H ions in a solution. The pH scale ranges from acids 1-7 and bases 7-14.[|What is acid rain?]