In this activity, students use their knowledge of thermochemistry to investigate a claim related to a kerosene fueled campstove.
The color of a thermochromic system depends on its temperature. The colors of leuco dye-based systems can also be influenced by adding acids or bases to the thermochromic reactions. These can be used to create colorful demonstrations of acid-base chemistry. Thermochromism found in color changing cups can also be used to visualize heat flow, and therefore thermodynamic principles, associated with stretching and contracting elastomers.
Placing dry ice in limewater is a great demonstration to accompany discussions on a variety of chemical topics, including the impact of ocean acidification on marine organisms that depend upon the formation of CaCO3.
Dean Campbell tries to use at least one demo for every class to illustrate concepts described in his chemistry courses. In this post, he includes short descriptions of the demonstrations and props he has used while teaching his collegiate General Chemistry II courses.
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.