Difference between revisions of "Base"
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== pH Scale ==
== pH Scale ==
The pH scale measures how acidic or basic a substance. the scale goes from 0 to 14; the middle of the scale, 7, is
The pH scale measures how acidic or basic a substance. the scale goes from 0 to 14; the middle of the scale, 7, is neutral. Any substance that has a pH above 7 is basic and any substance below 7 is acidic. Weak bases are those that are closer to pH while strong bases are closer to 14.[http://www.elmhurst.edu/~chm/vchembook/184ph.html]
== Uses ==
== Uses ==
Revision as of 21:58, 3 May 2009
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The most defining property of bases is their ability to readily accept hydrogen ions. Another major property of bases is their reaction with acids. When an acid and a base are mixed the base reacts with the acid and neutralizes its acidity. A slippery sensation is attributed to basic solutions when touched. When tasted, bases are very bitter and give certain foods their bitter taste where they are present. When red litmus is exposed to a basic solution, it changes from a red hue to a blue one.
The three most prominent definitions of bases are Arrhenius bases, Brönsted-Lowry bases, and Lewis bases.
An Arrhenius base is one that gives up hydroxide ions into aqueous solutions. This definition was put forth by the Swedish chemist Svante Arrhenius in the 1880s. This definition is outdated because it only concerns bases in aqueous solutions and does not take into consideration basic compounds that do not have an OH group. As a result this is the most narrow of the three definitions of bases(Cox, Porch, Wetzel, p389-390).
A Brönsted-Lowry base is defined as a substance which receives protons. This definition was created by a Danish chemist by the name of J. N. Brönsted and a British chemist named I. M. Lowry in 1923 (Cox, Porch, Wetzel, p391). Brönsted-Lowry bases are paired with acids, forming what is referred to as conjugate pairs. When a Brönsted-Lowry acid goes through deprotonation (the process of losing a proton) it forms something that will readily receive a proton, forming the conjugate base. The same is true when the process is reversed and a Brönsted-Lowry base becomes the conjugate acid. All bases that fall under the definition of an Arrhenius base are also a Brönsted-Lowry base and, because the Brönsted-Lowry definition is more broad, it includes bases that do not fall under the Arrhenius definition.
(Cox, Porch, Wetzel, p389-340)
The pH scale measures how acidic or basic a substance. the scale goes from 0 to 14; the middle of the scale, 7, is neutral. Any substance that has a pH above 7 is basic and any substance below 7 is acidic. Weak bases are those that are closer to pH 7 while strong bases are closer to pH 14.
Bases are used in cleaning solutions because they can dissolve grease.
Bases are used in nature. In the human body, bases are used to neutralize the acidity of acids to prevent them from harming organs.
- Bases ScienceByJones.com, Larry Jones, March 2, 2007.
- Chemistry for Christian Schools, Heather E. Cox, Thomas E. Porch, D.M.D., John S Wetzel, M.S,. Bob Jones University Press.
- pH Scale Virtual Chembook. Elmhurst College. Charles E. Ophardt. 2003.