The Self-Carving Pumpkin: It's Not Just for Halloween!
Learn the chemistry behind the reaction between calcium carbide and water...melon...?!
Learn the chemistry behind the reaction between calcium carbide and water...melon...?!
This activity allows for the simple and accurate determination of the heat of vaporization, ΔHvap, of water at 100°C, and ultimately the approximate strength of a hydrogen bond in boiling water, in kJ·mol–1.
This activity is an interesting way to engage students before formally beginning the study of Thermochemistry. Students experiment and compare the use of 1% milk and half & half cream in coffee.
This lab guides students through taking data and constructing their own heating curve for water. It requires no special equipment, is low prep, is safe, and can even be done at home for homeschool or distance learning. Even though the lab activity itself is relatively simple and straightforward, the concepts still engage students in higher level thinking and gives them important practice with laboratory techniques and forming hypotheses.
The importance of surface area can be illustrated by adding spherical solids at known sizes and temperature to other substances at different temperatures and then monitoring the rates of temperature changes of the system over time. Larger spheres (with less surface area per sample) exchanged heat with water more slowly than smaller spheres, and less thermally conductive glass spheres exchanged heat with water more slowly than iron spheres. Additional, more colorful demonstrations are described in which small glass spheres cool thermochromic plastic cups more quickly than larger glass spheres.
Flash rocks, typically pieces of quartz that produce light when struck together, are an example of the complex phenomenon of triboluminescence. The green chemistry aspects for the flash rock demonstration are considered, and LEGO models illustrating quartz crystals, piezoelectric materials, and nonpiezoelectric materials are presented.
Nora Walsh shares the outline of the interactive notebook pages she uses for her thermochemistry unit. All of the documents and foldables are available for download.
The reaction of hydrogen and oxygen gases to form water is well known to be an exothermic reaction. That reaction can occur by first absorbing the hydrogen into palladium metal, and then placing the resulting palladium hydride into contact with oxygen in the air. Infrared and visible light videos were recorded for this process involving palladium foil, and the Green Chemistry and safety aspects of these activities are considered.
The "Two-Faced" thionin reaction involves causing a purple solution to fade to colorless by shining light on the solution. I wondered if it could be demonstrated the color of light that caused this transition.
Did you know that sand can be converted into a mixture of gases that spontaneously ignites in air? The procedures involved are relatively simple to perform, spectacular to observe, and relate to a rich assortment of chemical principles.