When using standard thermodynamic values, the chemical reaction whereby ATP is converted to ADP is found to have a positive value for ΔG. This would imply the reaction REQUIRES energy. However, analyzing the process under physiological conditions shows that ΔG is in fact negative, as expected.
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.
From bond energies to thermochemical equations, explore the convergence of pathways to the same result in teaching Hess’s Law of Heat Summation.
Pharaoh's serpent is the name of a very interesting chemical reaction that produces a snake-like foam. Unfortunately, it requires the use of a toxic mercury compound. Explore this very similar reaction that can be achieved quite simply by using fuel tablets and calcium gluconate tablets and learn a lot about the chemistry that is involved!
This activity allows for the simple and accurate determination of the heat of fusion, ΔHfusion, of water at 0°C.
Igniting paper towels that have been soaked in concentrated potassium nitrate and allowed to dry yields a flame reminiscent of that produced by guncotton. Repeating this experiment with other metal nitrates produces flames with different colors, plus a few other chemical surprises! This series of experiments is fascinating and connects to a wide variety of chemical topics including combustion, redox reactions, chemical thermodynamics, and flame tests. You don't want to miss this one!
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.
Learn the chemistry behind the reaction between calcium carbide and water...melon...?!
