Acids/Bases - Theory

History

Explore the discoverer's biography, including general facts about his life and anecdotes regarding how he made this particular discovery. Also see other significant scientific discoveries built largely on this concept and other real-world applications in history that may not still be relevant.

Discoverer/Developer

Gilbert Lewis (1875-1946) was born in Weymouth, Massachusetts. At the age of 14, Lewis started college at the University of Nebraska. After getting his PhD at Harvard, he taught at MIT. He eventually became a professor at the University of California, Berkeley. Lewis became part of the National Science Academy in 1913. He did work on relativity and light and matter interactions that complimented Einstein's work on the subject. His student Harold Urey received the Nobel Prize in Chemistry for discovering deuterium. In 1916, he published a paper on the covalent bond, and in 1923 he published his theory on acids and bases. The idea of giving students problem sets from which to practice and learn chemistry was largely due to Lewis and his teaching philosophy. Lewis was nominated for the Nobel Prize 35 times, but never received it. Found dead on the floor of his laboratory in Berkely, there is debate as to whether Lewis's death might have been a suicide.

 

Concept Definition

Study the primary definition of this concept, broken into general, basic, and advanced English definitions. Also see the mathematical definition and any requisite background information, such as conditions or previous definitions.

Basic

A Lewis acid accepts a pair of electrons while a Lewis base donates a pair of electrons.

Advanced

A Lewis acid accepts a pair of electrons while a Lewis base donates a pair of electrons.

Some examples include:

1. $\text{BF}_3{(g)} + \text{:NH}_3{(g)} \to \text{F}_3\text{BNH}_3{(s)}$

2. $\text{:NH}_3{(g)} + \text{HCl}{(aq)} \to \text{NH}_4\text{Cl}{(s)}$

3. $\text{Cr}^{3+}{(aq)} +\text{6H}_2\text{O}{(l)} \to \text{Cr(H}_2\text{O})_6^{3+}{(aq)}$

 

Vocabulary

Learn important vocabulary for this concept, including words that might appear in assessments (tests, quizzes, homework, etc.) that indicate the use of this concept.

 Important Vocabulary

Term Context

 

Classroom Demonstations

Investigate lab procedures suitable for live classroom demonstrations or guided student exploration.

Students requiring adaptations to gain the full benefit of a demonstration may find a worksheet with guided observations useful. Alternatively, a teacher may wish to use a worksheet with guided observations to model what observations all students should be making during a demonstration.

The Demonstration Observation Worksheet is available in

  • PDF [ready to print]
  • Word 2007/2008 DOCX [free to edit/adapt further]

 Demos

White Smoke



Demonstrations

   
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White Smoke

No Picture
 
Author: brendzel
Description:
In this Lewis acid/base reaction, the combination of HCl (the Lewis acid) and Ammonia (the Lewis base) forms ammonium chloride, a white gas.
Usage:
No Description available
 
 
Safety:
Do experiment in a fume hood. Wear googles and gloves when preforming the experiment.
 
Equipment:
2 glass jars or beakers the same size that are around 250 mL A piece of cardboard big enough to cover the top of a jar/beaker
 
Materials:
Around 20 mL of ammonia Around 20 mL of hydrochloric acid (HCl)
 
Procedure:
Put a tiny amount of HCl in one beaker.  Pour in just enough to coat the sides and bottom of the beaker, and pour the excess down the sink.  Place cardboard on top of beaker. In the other beaker, add the ammonia. Invert the beaker with the HCl and cardboard so it is on top of the beaker with ammonia. Pull out the cardboard.  White smoke should appear.
 
Notes:
No Description available
 
Disposal:
All materials may go down the drain.
 
Difficulty:No specific experience required
Preparation Time:5 minutes Demonstration Time: 1 minutes
Availability of Materials:Local grocery store
Cost of materials:
Last Updated:Tue 09 Aug 2011 12:45:25 EDT Viewed:14762 times viewed
Source:Sarah Brendzel, May 5, 2011, About.com

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Works Cited

Review the works cited to write the researched parts of this page, such as the discover's biographical information and other areas.

 Works Cited

http://www.woodrow.org/teachers/ci/1992/Lewis.html

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