An experiment is demonstrated to determine the percentage of oxygen in air using a pretreated piece of steel wool, which is an alternative to spectroscopic kinetic analysis. Students are able to determine the order of reaction for oxygen in its reaction with the iron in steel wool, and are able to use the existing technology to collect and analyze…

This article describes the reaction between nitrite and safranine O. This sensitive reaction is based on the disappearance of color of the reddish-orange azo dye, allowing the determination of nitrite at the mg mL-1 level. A factorial optimization of parameters was carried out and the method was applied for the quantification of nitrite in…

Oscillating reactions have been extensively used in chemical demonstrations. They involve several chemical concepts about kinetics, catalysts, and thermodynamics. The spontaneous cyclic color change of a solution is an attraction in any educational-level course. Chemiluminescent reactions are also among the most fascinating demonstrations and have…

Identifies the misunderstandings and problem-solving strategies of secondary students when solving stoichiometry problems. (Author/CCM)

The widely used method of synthesizing HCl and DCl gases for infrared analysis by hydrolysis of benzoyl chloride includes a potentially dangerous final step whereby the frozen product is allowed to heat and expand into an infrared gas cell. The subsequent rapid rise in vapor pressure can "pop" open glass joints in the vacuum line and vent the…

Do students who focus on some content areas in high school chemistry have an advantage over others in college chemistry? Published research on high school preparation for college science dates back as far as the 1920s, but results have been mixed. This manuscript seeks to answer this question through the use of a broad-based survey of 3521…

Discusses ways of teaching the mole concept in high school chemistry classes. Provides resource information on the mole and Avogadro's Number. Includes an explanation of four methods for measuring Avogadro's Number and instructions on how to use the mole. (MA)

Teachers and students alike report difficulties with the measurement unit called mole. This article tries to demonstrate that mole and the corresponding quantity are not exceptional. Mole lacks the context of a given amount because the unit measures the relative number of atoms compared with those present in a standard. Discusses history of…

Investigates HyperCard as a tool for assessment in science education and determines whether or not a HyperCard assessment instrument could differentiate between expert and novice student performance on balancing stoichiometric equations in science education. (ZWH)

The study focuses on percarbonate-based stain removers since the percarbonate can be heated to produce additional sodium carbonate. An experiment that provides general chemistry students an opportunity to apply their knowledge of basic stoichiometry to solve a relevant, real-world problem is described.

This study researched the use of writing-to-learn strategies within a high-school (Year 11) chemistry classroom. The writing task itself asked the students to write a business letter to a younger audience of middle-school (Year 7) students. A mixed-method design was used for the study, incorporating pre/post- testing with semi-structured…

Purpose: Research on the nature of blended learning and its features has led to a variety of approaches to the practice of blended learning. The purpose of this paper is to provide an alternative practice model, the TSOI hybrid learning model (HLM) to enhance the blended learning experiences in science education. Design/methodology/approach: The…

Indicates that the concept of definite proportions or constant composition should be introduced with qualification. Presents arguments against the Law of Definite Proportions and cites examples in the areas of solid solutions, compounds of the transition and inner transition elements, and in some compounds of the representative elements. (GS)

Presents experiments involving the analysis of commercial products such as carbonated beverages and antacids that illustrate the principles of acid-base reactions and present interesting problems in stoichiometry for students. (JRH)