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ERIC Number: EJ1452924
Record Type: Journal
Publication Date: 2023-Dec
Pages: 6
Abstractor: As Provided
ISBN: N/A
ISSN: ISSN-0021-9584
EISSN: EISSN-1938-1328
Available Date: N/A
Visualization of Validity Ranges for Acid Approximations: Error Contour Plots as a Function of Concentration and K[subscript a]
Journal of Chemical Education, v100 n12 p4884-4889 2023
Approximate mathematical treatments are commonly taught in undergraduate chemistry, but the validity ranges of these approximations have rarely been properly defined. We present error contour plots of commonly used quadratic approximations for calculating equilibrium proton concentrations of monoprotic acids. Students and instructors can easily read these plots to estimate the error in their approximation of proton concentration (1%, 5%, 10%, and 25%) at a given initial acid concentration [HA][subscript 0] and dissociation constant K[subscript a] value. In addition, we introduce a new quadratic expression which will always deliver an error no larger than 25% (or 0.1 pH unit) in ideal solution irrespective of the acid strength and concentration. These results extend readily to their analogue of pOH, K[subscript b], and [A[superscript --]] for bases. Our novel approach here could significantly reduce many different situations students must master into one that can be computed straightforwardly without caveats or conditions.
Division of Chemical Education, Inc. and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail: eic@jce.acs.org; Web site: http://pubs.acs.org/jchemeduc
Publication Type: Journal Articles; Reports - Research
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A
Author Affiliations: N/A