Chemistry Project: Acids and Bases & the pH Scale
Acids and Bases are two groups of chemical compounds that generally have opposite
characteristics. They have there own unique traits, acids taste sour, turn litmus red while
bases taste bitter and turn litmus blue. The term pH relates to measuring the acidity or
alkalinity of a solution, such as vinegar, or even a damp substance like soul.
The neutral pH is 7, which is essentially water, with lower numbers indicating acidity and
higher numbers indicating alkalinity. Hydronium ions (H3O+) are formed when water
molecules (H2O) bond with hydrogen ions (H+). Hydronium ions are positively charged
because of their extra hydrogen ion. Hydroxide ions (OH-) are produced when water
molecules (H2O) ionize to become hydronium ions (H3O+) and hydroxide ions (OH-).
Substances with a high concentration of hydroxide ions are bases. Bases have a pH rating
of seven or higher. Solutions of ions conduct an electric current, similar in the way that
wire does. Ions can move about in a solution and carry a charge. If they can do carry the
charge they are electrolytes.
The Bronsted-Lowry theory states that an acid is a proton donor and a base a
proton acceptor. Although the acid must still contain hydrogen, the Bronsted-Lowry
theory does not require an aqueous medium. The Bronsted-Lowry definition of acids and
bases also explains why a strong acid displaces a weak acid from its compounds and
likewise for strong and weak bases. In the Lewis theory of acid-base reactions, bases
donate pairs of electrons and acids accept pairs of electrons. A Lewis acid is any
substance, such as the H+ ion, that can accept a pair of nonbonding electrons. Therefore, a
Lewis acid is an electron-pair acceptor. A Lewis base is any substance, such as the OH-
ion, that can donate a pair of nonbonding electrons. A Lewis base is therefore an
electron-pair donor.
Svante Arrhenius was a Swedish chemist who helped lay the foundation of
modern day chemistry. When he was a student, he studied the
characteristics. They have there own unique traits, acids taste sour, turn litmus red while
bases taste bitter and turn litmus blue. The term pH relates to measuring the acidity or
alkalinity of a solution, such as vinegar, or even a damp substance like soul.
The neutral pH is 7, which is essentially water, with lower numbers indicating acidity and
higher numbers indicating alkalinity. Hydronium ions (H3O+) are formed when water
molecules (H2O) bond with hydrogen ions (H+). Hydronium ions are positively charged
because of their extra hydrogen ion. Hydroxide ions (OH-) are produced when water
molecules (H2O) ionize to become hydronium ions (H3O+) and hydroxide ions (OH-).
Substances with a high concentration of hydroxide ions are bases. Bases have a pH rating
of seven or higher. Solutions of ions conduct an electric current, similar in the way that
wire does. Ions can move about in a solution and carry a charge. If they can do carry the
charge they are electrolytes.
The Bronsted-Lowry theory states that an acid is a proton donor and a base a
proton acceptor. Although the acid must still contain hydrogen, the Bronsted-Lowry
theory does not require an aqueous medium. The Bronsted-Lowry definition of acids and
bases also explains why a strong acid displaces a weak acid from its compounds and
likewise for strong and weak bases. In the Lewis theory of acid-base reactions, bases
donate pairs of electrons and acids accept pairs of electrons. A Lewis acid is any
substance, such as the H+ ion, that can accept a pair of nonbonding electrons. Therefore, a
Lewis acid is an electron-pair acceptor. A Lewis base is any substance, such as the OH-
ion, that can donate a pair of nonbonding electrons. A Lewis base is therefore an
electron-pair donor.
Svante Arrhenius was a Swedish chemist who helped lay the foundation of
modern day chemistry. When he was a student, he studied the
Bibliography: (1) Introduction to pH. Omega Engineering Inc. 2001 http://www.omega.com/techref/ph.html Accessed June 2nd, 2004 (2) What do pH, Blood, and Food have in Common? http://ndnd.essortment.com/phbloodfood_rvbk.htm Accessed on June 6th, 2004 (3) Carpi, Anthony. Acids and Bases: An Introduction. National Science Foundation. 2003 http://www.visionlearning.com/library Accessed June 6th, 2004 (4) Clark, Jim http://www.chemguide.co.uk/physical/acidbaseeqia/indicators.html Accessed on June 5th, 2004 (6) Nance, Matthew. General Chemistry Lecture Demonstrations and Audio Visual Resources. University of Indiana, 2003 Accessed on June 4th, 2004. (7) Senese, Fred. What is pH?. General Chemistry Online. 1997-2004 http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/what-is-pH.shtml Accessed on June 4th, 2004 (8) Visuals: Accessed June 5th, 2004