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thermochemistry

Amount and rate of heat transfer using iron spheres and liquid nitrogen

Dean Campbell | Tue, 06/04/2024 - 11:00

When iron spheres at room temperature are added to liquid nitrogen, the nitrogen boils as heat is transferred in from the iron. The amount of liquid nitrogen boiled depends on the amount of heat transferred, which depends on the mass of the iron added. However, the rate at which liquid nitrogen boils depends on the surface area of the iron in contact with the liquid nitrogen. These phenomena can be studied with experiments which measure the mass lost by the boiling liquid nitrogen.

Seashell Chemistry

Tom Kuntzleman | Thu, 06/01/2023 - 14:15

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.

Upgrading a Classic Science Demonstration

Josh Kenney | Mon, 02/27/2023 - 09:31

In a classic demonstration of energy conservation, smashing two large steel ball bearings generates sufficient heat to burn a hole through a piece of paper. Josh Kenney found this demonstration underwhelming because the paper doesn't look burned. So, he upgraded the experiment by covering the paper in Elmer's Color Changing Glue. Now, a spectacular color change reveals the increase in heat!

Expanding on Self-Inflating Balloons: Activities Involving Moles, Gas Laws, and Thermochemistry

Dean Campbell | Thu, 02/10/2022 - 08:42

Balloons that inflate using carbon dioxide produced from the reaction of citric acid and sodium hydrogen carbonate can be used to demonstrate a number of aspects of chemistry. Gas laws were used with the balloons to illustrate limiting reactants, molar mass of gases, and rockets. The endothermic reaction in the balloon was visualized with an infrared camera, and the Green Chemistry aspects of these balloons were considered.