The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
pH refers to the amount of acid or base in an aqueous solution. It comes from a French word meaning "hydrogen power", or essentially the strength of the hydrogen ion. pH is defined as the negative log (in base 10) of the hydrogen ion concentration. A neutral solution has a pH of 7.0, acidic solutions are those with a pH less than 7, and basic solutions are those greater than 7. Since this is a logarithmic scale, the difference between each increment is a factor of 10. Thus, a solution of pH 5.0 is 10 times more acidic than a solution of pH 6.0, and 100 times more acidic than the solution of pH 7.0. Battery acid has a pH of nearly 1.0, normal stomach acidity ranges from 1.0 to 3.0, lemon juice is around 2.3, vinegar and soft drinks about 3.0, fresh tomatoes about 4.0, black coffee about 5.0, pure water 7.0, blood 7.3-7.5, sea water 7.8-8.3, baking soda and bleach 9.0, household ammonia and detergents 10.5-12.0, hair remover 12.5, and oven cleaner 13.5.
The pH of a solution can be measured using an electronic pH meter with electrodes, and by various indicators which change color depending upon the pH of the solution. For example, phenophthalein is colorless in an acidic solution but turns pink around pH 8.3.
Normal rain water has a pH of approximately 5.6 due to the reaction of carbon dioxide gas and water vapor in the atmosphere, producing weak carbonic acid. Acid rain is rain water with a pH less than this, and areas receiving high amounts of nitrous oxide and sulfur dioxide emissions receive more acidic rain water due to the production of the stronger nitric and sulfuric acids in the atmosphere. Acid deposition (both wet and dry) can cause considerable damage to unbuffered aquatic and terrestrial environments. It can also erode marble statues.