The book Chemistry on a Budget contains inexpensive chemistry labs that are useful with easy to obtain materials.
There are two versions of each lab, one with a ten-question conclusion and one with directions for a full lab report. This way the teacher has the option! Each lab is two pages to allow for one two-sided handout.
You can buy this lab book for $23 at amazon.com or lulu.com. It will take 1-2 weeks to get to you -- Order Now. It’s a great resource!
*Some of you have already purchased my lab book – be sure to check out Page 141 !
“Physicists at the Swiss Nanoscience Institute and the University of Basel have succeeded in measuring the very weak van der Waals forces between individual atoms for the first time. To do this, they fixed individual noble gas atoms within a molecular network and determined the interactions with a single xenon atom that they had positioned at the tip of an atomic force microscope. As expected, the forces varied according to the distance between the two atoms; but, in some cases, the forces were several times larger than theoretically calculated.” https://www.unibas.ch/en/News-Events/News/Uni-Research/Physicists-Measure-van-der-Waals-Forces-of-Individual-Atoms-for-the-First-Time.html
“Researchers say that they have made the first ever direct measurements of the strength of the tiny van der Waals forces passing between individual atoms. At the University of Basel in Switzerland they studied interactions between isolated atoms of the inert noble gases xenon, argon and krypton using ultra-sensitive low-temperature atomic force microscopy (AFM).”
“Van der Waals forces act like a sort of quantum glue on all types of matter. Using a new measuring technique, scientists from Forschungszentrum Julich experimentally determined for the first time all of the key details of how strongly the single molecules bind to a surface. With an atomic force microscope, they demonstrated that the forces do not just increase with molecular size, but that they even grow disproportionately fast.”
“…van der Waals forces are among the weakest, yet most decisive interactions governing condensation and aggregation processes and the phase behavior of atomic and molecular matter.
Van der Waals interactions arise due to a temporary redistribution of electrons in the atoms and molecules. This results in the occasional formation of dipoles, which in turn induce a redistribution of electrons in closely neighboring molecules.
Due to the formation of dipoles, the two molecules experience a mutual attraction, which is referred to as a van der Waals interaction. This only exists temporarily but is repeatedly re-formed.
The individual forces are the weakest binding forces that exist in nature, but they add up to reach magnitudes that we can perceive very clearly on the macroscopic scale.”
“What is the reason for the superlinear increase? The van der Waals force, to put it simply, emerges due to the displacement of electrons in the shells of atoms and molecules, caused by quantum fluctuations, which leads to a weak electrical attraction. In the case of larger molecules, more atoms are involved as each of these molecules also comprises more atoms. And on top of this, each and every atom contributes more strongly.
‘As large organic molecules often form electron clouds that stretch across the entire molecule, they offer electrons considerably more room to manoeuvre than a single atom,’ says the head of the young investigators group at Jülich, Dr. Ruslan Temirov. ‘This makes them easier to displace, which overproportionally increases the electrical attraction.’ ”
“Van der Waals forces act between non-polar atoms and molecules. Although they are very weak in comparison to chemical bonds, they are hugely significant in nature. They play an important role in all processes relating to cohesion, adhesion, friction or condensation and are, for example, essential for a gecko's climbing skills.
Van der Waals interactions arise due to a temporary redistribution of electrons in the atoms and molecules. This results in the occasional formation of dipoles, which in turn induce a redistribution of electrons in closely neighboring molecules. Due to the formation of dipoles, the two molecules experience a mutual attraction, which is referred to as a van der Waals interaction. This only exists temporarily but is repeatedly re-formed. The individual forces are the weakest binding forces that exist in nature, but they add up to reach magnitudes that we can perceive very clearly on the macroscopic scale - as in the example of the gecko.”
This is an example of current research that is directly related to a concept you teach during Introductory Chemistry.
*This Blog contains several entries that would be helpful to your chemistry classroom. Check out the Topic List to help you to find past Blog entries.
Also, Write To Me about your successes, challenges, or questions in the Chemistry Classroom.
Remember, buying a copy of the lab book Chemistry on a Budget can be very useful to your Chemistry classroom with labs and class article ideas.
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