Island Explorations: Discovering Effects of Environmental Research-Based Lab Activities on Analytical Chemistry Students

2014 ◽  
Vol 91 (11) ◽  
pp. 1887-1894 ◽  
Author(s):  
Janice Hall Tomasik ◽  
Dale LeCaptain ◽  
Sarah Murphy ◽  
Mary Martin ◽  
Rachel M. Knight ◽  
...  
Keyword(s):  
Analytical Chemistry ◽  
Environmental Research ◽  
Chemistry Students

Analytical chemistry students’ explanatory statements in the context of their corresponding lecture

2020 ◽  
Vol 21 (4) ◽  
pp. 1183-1198
Author(s):  
Ying Wang ◽  
Scott E. Lewis
Keyword(s):  
Analytical Chemistry ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Formal Education ◽  
Limited Information ◽  
Acid Base ◽  
Secondary Chemistry ◽  
Chemistry Students ◽  
Post Secondary ◽  
Layer Chromatography

Conceptually understanding chemistry requires the ability to transition among representational levels to use an understanding of submicroscopic entities and properties to explain macroscopic phenomena. Past literature describes student struggles with these transitions but provides limited information about upper-level post-secondary chemistry students’ abilities to transition among levels. This group is of particular interest as they are engaging in potentially their final training before entering a career as professional chemists, thus if students are likely to develop this skill during their formal education it should be manifest among this group. This study characterized analytical chemistry students’ responses to open-ended assessments on acid–base titrations and thin-layer chromatography for the use of sub-microscopic entities or properties to explain these macroscopic phenomena. Further, to understand whether explanatory statements were an expectation inherent in the instructional context of the setting, the analytical chemistry instructor's lectures on acid–base titrations and thin-layer chromatography were analyzed with the same framework. The analysis found that students seldom invoked explanatory statements within their responses and that congruence between lectures and responses to assessment was primarily limited to the use of macroscopic, descriptive terms. Despite the fact that the lecture in class regularly invoked explanatory statements in one context, this did not translate to student use of explanatory statements. To further test the hypothesis that analytical chemistry students struggle with explanatory statements, a follow-on study was also conducted among a second cohort of students reviewing their responses when specifically prompted to use sub-microscopic entities to explain a macroscopic phenomenon. The results suggest that fewer than half of the students showed proficiency on generating explanatory statements when explicitly prompted to do so. Instructional implications to promote explanatory statements are proposed in the discussion.

Trace Analytical Capabilities of Total-Reflection X-ray Fluorescence Analysis

1984 ◽  
Vol 28 ◽  
pp. 75-83 ◽  
Author(s):  
W. Michaelis ◽  
J. Knoth ◽  
A. Prange ◽  
H. Schwenke
Keyword(s):  
Analytical Chemistry ◽  
Mechanical Design ◽  
Mineral Exploration ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
Environmental Research ◽  
X Rays ◽  
X Ray ◽  
Long Time ◽  
Preparation Techniques

AbstractThe principle to utilize total reflection of the primary X-rays in fluorescence analysis is known since a lot of years. Nevertheless, analytical chemistry did not profit from the inherent advantages of the method for a long time. The main reason for this failure was the lack of instruments which were easy to use in practice. A few years ago, however, the development of a proper mechanical design and of adapted sample preparation techniques led to commercially available spectrometers which throughout fulfill the demands for routine applications. Since then the utilization of Total-Reflection X-Ray Fluorescence Analysis (TXRF) has increased rapidly. The scope of work is meanwhile widespread over environmental research and monitoring, mineralogy, mineral exploration, oceanography, biology, medicine and biochemistry. Accordingly, numerous matrices have been handled.

scholarly journals THE IMPORTANCE OF TEACHING TITRATION CURVES IN ANALYTICAL CHEMISTRY

2020 ◽  
Vol 17 (34) ◽  
pp. 213-219
Author(s):  
Roberto FERNANDEZ-MAESTRE
Keyword(s):  
Analytical Chemistry ◽  
Acid Base ◽  
Acceptable Error ◽  
Chemistry Teachers ◽  
Chemistry Students ◽  
Undergraduate Chemistry ◽  
Titration Curves ◽  
Chemistry Textbooks ◽  
Ultimate Purpose ◽  
Selection Of

Titration curves are an essential subject of an Analytical Chemistry course. The main objective of calculating titration curves is the selection of an indicator for such titrations. The calculation of titration errors is imperative because they establish if a given indicator can be used for a given titration. This study reviews the available literature on titration curves and calculating their errors. Its purpose is to draw attention to the importance of undergraduate chemistry students having competencies to determine the titration errors rather than skills to build titration curves as the ultimate purpose of these curves is to determine the failure committed when using a given indicator to assess their endpoints. It is shown that the pH and potential calculation at the equivalence point in acid-base and redox titrations, respectively, are not required to choose the titration indicator, one that yields an acceptable error according to the type of application needed. Methods to calculate these errors in the four main types of titrations are presented; those for complexometric and precipitation titrations are simpler than in the literature. Here, it is also demonstrated that calculating points immediately after and before the curve inflection are more critical for this selection in these two types of titrations. Also, it is deducted that complexometric and precipitation curves are not required to select indicators for these titrations. These demonstrations are essential because analytical chemistry teachers may disregard teaching important topics by spending time calculating unnecessary titration curves (complexometric and precipitation titrations) or additional points of titration curves (redox and acid-base titrations) when the calculation of titration errors of these reactions is more critical. Most analytical chemistry textbooks neglect this topic. Undergraduate chemistry programs should focus more on calculating titration errors than on the construction of titration curves.

Making Sense of Errors Made by Analytical Chemistry Students in Their Writing

2015 ◽  
Vol 6 (3) ◽  
pp. 490
Author(s):  
Misiwe Katiya ◽  
Thembinkosi Mtonjeni ◽  
Puleng Sefalane-Nkohla
Keyword(s):  
Analytical Chemistry ◽  
Chemistry Students ◽  
Making Sense
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