Approximations can help to orient the student in an organic chemistry laboratory. There the student needs to develop the solvent systems for the reaction and isolation of organic reactants and products. The adage "like dissolves like" helps in this regard, but this approach is vague and entirely qualitative. More quantitative approaches…

In this article we consider a well-known simple, very accessible demonstration of surface tension with a small boat propelled by substances that change the surface tension of water. A simple quantitative evaluation is provided that matches well with experimental data. A modification to the experiment is proposed allowing it to continue for a long…

The concept of equilibrium vapor pressure plays a key role in the general chemistry curriculum; it is among the first and most easily demonstrated examples of equilibrium and frequently caps off the first semester of general chemistry where it illustrates the properties of liquids and intermolecular forces. We report here simple modifications of…

A significant challenge for the global community is the increasing demand for clean and renewable energy technologies. However, a lack of knowledge of these technologies threatens to impede their adoption. The development of cheap, effective, and easy-to-use chemical and electrochemical storage technologies is crucial if countries are to move away…

This article describes how by using three points to make a line and comparing the graphs for water and oil, students can mathematically demonstrate that Gatorade dissolves in water much more readily than in oil. Students can also use units to understand and solve a multi-step problem by observing the color of each solution, making conductivity…

A computational chemistry exercise for the undergraduate physical chemistry laboratory is described. In this exercise, students use the molecular dynamics package Amber to generate trajectories of bulk liquid water for 4 different water models (TIP3P, OPC, SPC/E, and TIP4Pew). Students then process the trajectory to calculate structural (radial…

Flotation as a method of separation is widely researched and is applied in many industries. It has been used to address a wide range of environmental issues including treatment of wastewater, recovery of heavy metals for recycling, extraction of minerals in mining, and so forth. This laboratory attempts to show how such a simple method can be used…

This article looks at the events that led to the discovery of isotopes in the early part of the 20th century. It is difficult to claim that the discovery was a single event. A number of famous scientists worked independently to provide the evidence, and the understanding of the need to think differently about atoms gradually emerged. Four varied…

This advanced undergraduate laboratory experiment involves the synthesis and characterization of a metal-organic framework with microporous channels that are held intact via hydrogen bonding of the coordinated water molecules. The hydrothermal synthesis of Co[subscript 3](BTC)[subscript 2]·12H[subscript 2]O (BTC = 1,3,5-benzene tricarboxylic acid)…

The motion of charges around a centrally charged object is often compared to gravitational orbits (such as satellites around planets). Recently, a video taken by astronaut Don Pettit onboard the International Space Station shows water droplets orbiting a charged knitting needle. Here we attempt to model this motion and estimate the charges on the…

Even though density is taught in middle school, high school students often struggle to understand that the density of a substance is consistent regardless of amount. This is because many high school students know density = mass/volume, but do not have the conceptual understanding necessary to explain density-related phenomena. The scaffolded…

This "Science note" examines the bromination of phenol, a reaction that is commonly taught at A-level and IB (International Baccalaureate) as an example of electrophilic substitution. Phenol undergoes bromination with bromine or bromine water at room temperature. A white precipitate of 2,4,6-tribromophenol is rapidly formed. This…

The transport of water in plants is among the most difficult and challenging concepts to explain to students. It is even more difficult for students enrolled in an introductory general biology course. An easy approach is needed to demonstrate this complex concept. I describe visual and pedagogical examples that can be performed quickly and easily…

The glass electrode is the most commonly used device to access the pH of an aqueous solution. It attains highly accurate measurements via simple and well-established procedures. However, the reasons why the glass electrode potential scales with hydrogen ion concentration according to almost Nernstian potential values have been long-standing…

Elementary, middle-level, and high school science teachers commonly find their students have misconceptions about heat and temperature. Unfortunately, student misconceptions are difficult to modify or change and can prevent students from learning the accurate scientific explanation. In order to improve our students' understanding of heat and…