Energy conversion devices such as fuel cells, metal-air batteries, and electrolyzers have been envisaged as possible solutions for cutting down the continuous accumulation of greenhouse gases resulting from the combustion of fossil fuel. The bottleneck reaction for these devices is the oxygen reduction reaction (ORR) occurring at the cathode. The…

Climate change caused predominately by carbon dioxide (CO2) from fossil fuel use is a critical issue for our future. It is incumbent on science educators to learn about it and teach it in ways that illustrate the power of science to understand climatic changes and model past, present, and possible climate futures. It is equally important for…

An active-learning approach was employed in a project for our chemistry major students on the synthesis of biodiesel (BD) from an Amazon region oil. The project, involving activities in class and in the laboratory, was given during 8 weeks of the spring semester of 2022. The students were asked about their previous contact with the synthesis and…

In this paper, a problem set activity focused on understanding and applying unsupervised and supervised chemometric methods for the analysis of biodiesel-diesel blended fuels is described. This problem set was utilized in two upper-level analytical elective courses aimed for junior and senior level students. The data set consists of peak areas…

Calorimetry is a central concept in the first semester general chemistry curriculum, and constant pressure (coffee-cup) calorimetry is a common experiment in the laboratory. However, constant volume (bomb) calorimetry is traditionally reserved for the physical chemistry laboratory. This article describes the advantages of incorporating bomb…

The ideal gas law, "PV = nRT," is one of the simplest physical laws in nature that is introduced to students as early as in high school and first year in college. In this equation, "P" stands for pressure, "V" is the volume, "n" is the amount expressed in mole, "T" is the temperature in Kelvin…

The distinction between pressure in a liquid and in a gas is often treated in a cursory way, or not treated at all, even in university level textbooks. Most texts fail to point out the relation between pressure and density in a gas as compared to pressure in a--virtually incompressible--liquid. In many instances this also results in a dismissive…

In recent years, solar-powered photocatalytic water splitting for hydrogen production has drawn great attention as a method to supply clean energy and reduce environmental pollution. This approach, driven by solar energy to synthesize hydrogen gas, is completely renewable and can be used to power hydrogen fuel cells to effectively solve the global…

Various experiments on vibrating gas columns and on frequency measurements with glasses and pipes have been presented in recent years in the "iPhysicsLabs" column. The determination of the sound velocity in different gases by measuring the sound running time has also already been proposed in an earlier paper. This article now adds…

One of the most general aims of universities is to respond to the requirements of society. Health and safety are the most important aspects of professional work and play an important role in universities, as there, future professionals are trained for their future professional life. Scientific and technical degrees require adaptation to this…

The contemporary Human activity utilizes huge volumes of digital data to solve efficiently multiple socio-economic, scientific and technical problems. Now the big data analysis is mainly oriented to the socioeconomic sphere with a goal to lift the profit. The science and technology to penetrate deeper in the nature of objects and systems under…

We often say food and fuels "contain" energy. It is more accurate to say that energy is stored in the "fuel-oxygen system" generated during photosynthesis. It is definitely "not" stored in fuels or food (except for the very small amount of energy that can be obtained during anaerobic respiration). Aerobic respiration…

Nitrogen gas dominates the Earth's atmosphere but is largely ignored. Molecular nitrogen is extremely stable and so nitrogen is termed inert. What would happen if another 'inert' gas were the dominant species instead of molecular nitrogen? Here we show how unique nitrogen is and how important it has been to life on planet Earth.

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…

This work presents a sequence to introduce resistive gas sensors in the classroom. It explains the physical principle of the metal oxide semiconductor sensors and exemplifies its real interfacing through the sensor model MQ-2. Besides, it also presents the design of two electronic systems to indicate the level of alcohol concentration in the air,…