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July 23, 2013
Published by Bryan at July 23, 2013
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a required course on physical chemistry that deals with entropy and laws, ugh this is not what they want to know and, besides, "How useful will it be?" they naively ask. The problem is that it is impossible to avoid the use of mathematics, and they are not motivated to work through simple derivations.
August 5, 2011
Published by Bryan at August 5, 2011
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Explosions are vigorous chemical reactions that take place very rapidly and produce large volumes of gas and a lot of heat. For the explosives shown here, all are solids or liquids with a small volume relative to the huge amount of gas that is released in the explosion. The rapid production of a large volume of gas causes damage.
August 4, 2011
Published by Bryan at August 4, 2011
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The empirical formula is simplest whole number formula for a compound.
August 3, 2011
Published by Bryan at August 3, 2011
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Once atoms were found, it became evident that atoms were composed of protons, neutrons and electrons. The first model, due to J.J. Thomson, was the plum pudding model. This suggested that the atom was a positively charged cloud with electrons floating in it. This model is incorrect.
August 1, 2011
Published by Bryan at August 1, 2011
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At the energy we mostly deal with in chemistry matter is composed of atoms, molecules and ions. From a chemical point of view, these particles interact though the electromagnetic force.
March 9, 2011
Published by Bryan at March 9, 2011
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n 1887 J.J. Thomson discovery of the electron was a significant step that led to a much deeper understanding of the microscopic properties of Nature. In this entry, I will discuss the famous Millikan Oil drop experiment which was done in 1909.
But recall that in his characterization of the properties of the electron he could only determine the charge to mass ratio, given by -1.76 times ten to the 11th Coulombs per kilogram. Was this ratio a result of two big values or two small values?
Robert Millikan was able to separate the ratio in order to show that the ratio was that of two small numbers and in this way he was able to extract the elementary charge and the electron mass. Comparing the electron mass to that of the lightest element, Hydrogen, it is found that the mass of an electron is 1800 times smaller. Indeed at that time this was the smallest particle known.
February 14, 2011
Published by Bryan at February 14, 2011
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Discussion of the discovery of the electron by J. J. Thomson in 1897 using a cathode ray tube. He was able to obtain the charge to mass ratio, but not the actual mass or charge. Later Millikan was able to separate the two. Indeed Thomson found a new state of matter which laid the foundations for quantum mechanics and a huge range of technologies
February 20, 2010
Published by Bryan at February 20, 2010
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httpvh://www.youtube.com/watch?v=B68CEj9KveI In this clip the Aufbau Principle of the electronic structure of the elements is shown as an example of the content of MCH multimedia’s General Chemistry tutorials. The Aufbau or building up principle makes use of the Hydrogen Orbitals and the Pauli Principle. Buy the General Chemistry Tutorial from MCH […]