pH 역설: 수소 이온 농도를 이용하여 정의한 pH의 내재적 한계와 이에 대한 예비과학교사의 이해
pH paradox: Inherent limitation of pH defined using hydrogen ion concentration and preliminary science teachers’ understanding
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초록
본 연구에서는 로 산의 세기를 정의하는 간략화된 지식 속에 내재된 한계를 되짚어보고, 이에 대한 예비과학교사들의 이해를 조사하기 위하여 ‘pH 2.0 염산 용액 만들기 활동’을 실시하였다. 현재 pH의 정의는 수소 이온 농도에 기반을 두었기 때문에 수용액의 농도가 감소하면서 활동도는 증가하는 경우 이론과 반대되는 결과가 나타나는 역설적 상황이 발생할 수 있다. 또한, 학교 현장에서 pH를 정량적으로 측정하는 데에 사용하는 장치인 pH 미터가 수소 이온의 농도가 아닌 수용액의 전위 값을 측정하기 때문에 학생들이 계산한 pH 값과 차이를 나타내기도 한다. 연구 결과 예비과학교사들은 의 내재적 한계를 이해하고 있으나, 이것이 pH를 계산하는 데에 있어서 유용하게 사용될 수 있다는 것을 받아들이고 있었다. 하지만 일부 예비과학교사들은 pH 미터의 값을 지나치게 신뢰하는 모습을 보이기도 하였다.
Abstract
In this study, an activity of ‘Making pH 2.0 Hydrochloric Acid Solution’ was conducted to reflect on the inherent limitations in the simplified knowledge of defining the acidity of a solution as and to investigate the understanding of preliminary science teachers. Since the current definition of pH is based on hydrogen ion concentration, a paradoxical situation may occur contrary to the theory where the activity increases as the concentration of the aqueous solution decreases. It also differs from the pH value calculated by students because the pH meter, a device used to quantitatively measure pH at school sites, measures the potential value of an aqueous solution rather than the concentration of hydrogen ions. We showed that preliminary science teachers understood the inherent limitations of , but accepted that it could be useful in calculating pH. However, some preliminary science teachers showed their excessive confidence in the value of the pH meter.
참고문헌 (34)
- 교육부, "2015 개정 과학과 교육과정", ~ (2015)
- 교학사, "고등학교 화학Ⅰ" (2015)
- 동아출판, "고등학교 화학Ⅰ" (2015)
- 미래엔, "고등학교 화학Ⅰ" (2015)
- 비상교육, "고등학교 화학Ⅰ" (2015)
- 와이비엠, "고등학교 화학Ⅰ" (2015)
- 이화심, "pH 측정 시스템의 표준화에 관한 연구", 대한화학회지, 42(4), pp.432~442 (1998)
- 지학사, "고등학교 화학Ⅰ" (2015)
- 천재교육, "고등학교 화학Ⅰ" (2015)
- Arrhenius S, "Über die Dissociation der in Wasser gelösten Stoffe", Zeitschrift für physikalische Chemie, 1(1), pp.631~648 (1887)
- Bates RG, "Report on the standardization of pH and related terminology", Pure and Applied Chemistry, 1(1), pp.163~168 (1960)
- Boisen O, "Quantifying the Cross-Sensitivity of Glass pH Electrodes in Alkaline Solutions", Journal of Chemical Education, 96(7), pp.1418~1423 (2019)
- Buck RP, "Measurement of pH. Definition, standards, and procedures(IUPAC Recommendations 2002)", Pure and Applied Chemistry, 74(11), pp.2169~2200 (2002)
- Burton RF, "Defining and teaching pH", Journal of Chemical Education, 84(7), pp.1129~ (2007)
- Debye P, "De la theorie des electrolytes. I. abaissement du point de congelation et phenomenes associes", Physikalische Zeitschrift, 24(9), pp.185~206 (1923)
- de Levie R, "Potentiometric pH measurements of acidity are approximations, some more useful than others", Journal of Chemical Education, 87(11), pp.1188~1194 (2010)
- Dhindsa HS, "Pre-service science teachers’ conceptions of pH", Australian Journal of Education Chemistry, 60, pp.19~24 (2002)
- Friedenthal H, "Die Bestimmung der Reaktion einer Flüssigkeit mit Hilfe von Indikatoren", Zeitschrift für Elektrochemie und angewandte physikalische Chemie, 10(8), pp.113~119 (1904)
- Graham DJ, "Development of the glass electrode and the pH response", Journal of Chemical Education, 90(3), pp.345~351 (2013)
- Harned HS, "The dissociation constant of acetic acid from 0 to 35° centigrade", Journal of the American Chemical Society, 54(4), pp.1350~1357 (1932)
- Harned HS, "The ionic concentrations and activity coefficients of weak electrolytes in certain salt solutions", Journal of the American Chemical Society, 50(12), pp.3157~3178 (1928)
- Hawkes SJ, "Teaching the truth about pH", Journal of Chemical Education, 71(9), pp.747~749 (1994)
- Kolb D, "The pH concept", Journal of Chemical Education, 56(1), pp.49~53 (1979)
- Lewis GN, "Outlines of a new system of thermodynamic chemistry", Proceedings of the American Academy of Arts and Sciences, 43(7), pp.259~293 (1907)
- MacInnes DA, "Criticism of a Definition of pH", Science, 108(2816), pp.693~ (1948)
- "Journal of Chemical Education", 2006, 752~757
- Myers RJ, "One-hundred years of pH", Journal of Chemical Education, 87(1), pp.30~32 (2010)
- Nakhleh MB, "Influence of levels of information as presented by different technologies on students' understanding of acid, base, and pH concepts", Journal of Research in Science Teaching, 31(10), pp.1077~1096 (1995)
- 박은정, "Analysis of Mathematical Structure to Identify Students’ Understanding of a Scientific Concept: pH Value and scale", 한국과학교육학회지, 30(7), pp.920~932 (2010), 한국과학교육학회
- Lewis GN, "Thermodynamics and the Free Energy of Chemical Substances" (1923), McGraw-Hill
- Sørensen SPL, "Ergänzung zu dermp Abhandlung : Enzymstudien II : Über die Messung und die Bedeutung der Wasserstoffionenkonzentration bei enzymatischen Prozessen", Biochemische Zeitschrift, 22, pp.352~356 (1909)
- Sørensen SPL, "On the determination and value of π0 in electrometric measurement of hydrogen-ion concentration", Cotes rendus des travaux du laboratoire Carlsberg, 15, pp.1~40 (1924)
- Spitzer P, "The history and development of a rigorous metrological basis for pH measurements", Journal of Solid State Electrochemistry, 15(1), pp.69~76 (2011)
- Watters DJ, "Student understanding of pH : "I don't know what the log actually is, I only know where the button is on my calculator"", Biochemistry and Molecular Biology Education, 34(4), pp.278~284 (2006)