This is an easy and inexpensive laboratory experiment in which undergraduate students at the Bachelor's degree level in Chemistry can measure formation constants of complexes [Ni(en)[subscript n](OH[subscript 2])[subscript 6-2n]][superscript 2]+ (n = 1, 2 or 3; en = ethylenediamine) through an acid-base titration. The background information…

Students beginning college chemistry are expected to arrive prepared with fundamental, prerequisite conceptual understanding and skills from high school. While some topics may be reviewed explicitly in the course, prerequisite material-including hidden prerequisites often overlooked by faculty-is typically considered assumed prior knowledge and…

Students who score within the bottom quartile on cognitive measures of math aptitude have been identified as at-risk for low performance in chemistry courses, with less attention as to "why" such differential performance persists. At-risk students struggle most differentially on assessment items related to the mole concept and…

A good understanding of ternary phase diagrams is required to advance and/or to reproduce experimental research in solid-state and materials chemistry. The aim of this paper is to describe the solutions to problems that appear when studying or determining ternary phase diagrams. A brief description of the principal features shown in phase diagrams…

The purpose of this randomized experimental study is to apply two socio-cognitive models to understand possible ways to improve students' learning outcomes in an online introductory chemistry learning environment. Specifically, the social presence theory suggested that students' sense of relatedness and learning motivation can be increased by a…

The "Atoms-First" approach has received considerable attention in the chemical education community over the past few years as an alternative to the standard reaction-based two-semester General Chemistry curriculum. The Atoms-First model emphasizes the electronic structure of the atom as a means to explain and rationalize chemical…

Analyzing and interpreting data is an important science practice that contributes toward the construction of models from data; yet, there is evidence that students may struggle with making meaning of data. The study reported here focused on characterizing students' approaches to analyzing rate and concentration data in the context of method of…

This paper reports a comparison of a group of higher-and lower-achieving undergraduate chemistry students, 17 in total, as separated on their ability in stoichiometry. This exploratory study of 17 students investigated parallels and differences in the students' general and domain-specific cognitive abilities. Performance, strategies, and mistakes…

A coding scheme is presented and used to evaluate solutions of seventeen students working on twenty five stoichiometry problems in a think-aloud protocol. The stoichiometry problems are evaluated as a series of sub-problems (e.g., empirical formulas, mass percent, or balancing chemical equations), and the coding scheme was used to categorize each…

Many students share the common belief that the limiting reactant in a chemical reaction is the reactant in the smallest quantity of material. To help students overcome this difficulty a hands-on activity for the limiting reactant concept was developed. The activity incorporates the three levels of representation (macroscopic, submicroscopic, and…

A simple 3-h physical chemistry undergraduate experiment for the quantitative analysis of acetic acid in household vinegar is presented. The laboratory experiment combines titration concept with electrolysis and an application of the gas laws. A vinegar sample was placed in the cathode compartment of the electrolysis cell. Electrolysis of water…

An experiment for analytical chemistry is presented that utilizes simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) to characterize colorless, hydrated salts with anhydrous melting points less than 1100 degrees C. The experiment could be used to supplement the lecture discussing gravimetric techniques. It is…

The ability to make realistic judgments of one's performance is a demonstration of the possession of strong metacognitive skills. In this study we investigate the relationship between accuracy of self-evaluation as an expression of metacognitive skill, and learning gain in stoichiometry. The context is an academic development programme at a South…

A guided-inquiry lab, suitable for first-year general chemistry or high school advanced placement chemistry, is presented that uses only inexpensive, store-bought materials. The reaction of sodium bicarbonate (baking soda) with aqueous acetic acid (vinegar), under the constraint of the challenge to completely fill a sealable plastic bag with the…

This article describes a method of instruction using an active learning strategy for teaching stoichiometry through a process of gradual knowledge building. Students identify their misconceptions and progress through a sequence of questions based on the same chemical equation. An infrared device and software registered as the TurningPoint Audience…