Water is a solvent with special biological properties. It is polar, meaning one side (oxygen) has a partial negative charge and the other (hydrogens) has a partial positive charge. It also has an emergent property, hydrogen bonding, that emerges when many molecules are present but not when one is alone, because the hydrogens can form weak bonds with oxygens on other molecules. This stabilizes the liquid and makes it more cohesive. It can undergo transpiration, has high adhesion and high surface tension, and also has a high heat capacity which lets it absorb a lot of heat energy without going up much in temperature. It has a high heat of evaporation, so it takes a lot of heat to vaporize it. This lecture also covers the basics of acids, bases, and pH.
is polar. The electrons are more strongly attracted to the more
electronegative oxygen molecule than to the hydrogen molecule..
Water molecules are held together through hydrogen bonds. This
bonding is responsible for some of the properties of water.
special properties make it essential to life. Water is both strongly
cohesive and adhesive, has a high surface tension and both high heat
capacity and a high heat of evaporation.
can be divided into either hydrophilic, meaning water loving,
or hydrophobic, meaning water fearing.
dissolves like. For example, hydrophilic substances dissolve in
increase the concentration of H+ in a solution. Bases decrease the
concentration of H+ in a solution.
pH scale is used to describe how acidic or basic a solution is.
Solutions with a lower pH are more acidic. Those with a higher pH
are more basic. A solution with a pH of 7 is neutral.
Properties of Water
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.
The book and CD package include two full length practice exams that are presented with all questions answered and explained. The author also presents detailed reviews of all test topics and includes multiple-choice and free-response questions with answers at the end of each topic's chapter.
This book includes a review of the AP Biology exam format and scoring, proven strategies for answering multiple-choice questions, and hints for tackling the essay questions. The practice tests include answers and explanations and there is also proven test-taking strategies for both the multiple choice and essay parts.