What you need to write better chemistry notes (and what not)?

Chemistry is one strange subject. It begins with a simple substance and goes above complex polymers - and, down to subatomic particles. I have been writing a lot recently on how to read, revise and make notes etc., to help you become a better student. Class notes aren't always the best solution and if you are aspiring to become a chemistry scholar one day - you must rise above the classroom notes and write your own for the change. This…

Nobel Prize Winners Chemistry 2013

The Nobel Prize in Chemistry 2013

  Classical mechanics is considered to be just opposite to quantum physics in terms of theory and practical models. Classical mechanics, especially Newtonian Mechanics, and quantum mechanics are definitely two fundamental but equally different branches of physics having no significant connection to each other. These completely disjoint subjects were glued by the work of the trio of Martin Karplus, Michale Levitt and Arieh Warshel, the professors of chemistry from the universities of United States of America in decade of 1970s.…

Spin-orientation

Consequences of Light Absorption – The Jablonski Diagram

All about the Light Absorption’s theory on the basis of Jablonski diagram. According to the Grotthus – Draper Law of photo-chemical activation: Only that light which is absorbed by a system, can bring a photo-chemical change. However it is not true that all the kind of light(s) that are absorbed could bring a photo-chemical change. The absorption of light may result in a number of other phenomena as well. For instance, the light absorbed may cause only a decrease in the intensity…

Classical Theory of Raman Scattering

The classical theory of Raman effect, also called the polarizability theory, was developed by G. Placzek in 1934. I shall discuss it briefly here. It is known from electrostatics that the electric field $ E $ associated with the electromagnetic radiation induces a dipole moment $ mu $ in the molecule, given by $ \mu = \alpha E $ .......(1) where $ \alpha $ is the polarizability of the molecule. The electric field vector $ E $ itself is given…

The Lindemann Theory of Unimolecular Reactions

[ Also known as Lindemann-Hinshelwood mechanism. ] It is easy to understand a bimolecular reaction on the basis of collision theory. When two molecules A and B collide, their relative kinetic energy exceeds the threshold energy with the result that the collision results in the breaking of comes and the formation of new bonds. But how can one account for a unimolecular reaction? If we assume that in such a reaction $ A \longrightarrow P $ , the molecule A…

Cvraman

Raman Effect- Raman Spectroscopy- Raman Scattering

In contrast to other conventional branches of spectroscopy, Raman spectroscopy deals with the scattering of light & not with its absorption. Raman Effect Chandrasekhar Venkat Raman discovered in 1928 that if light of a definite frequency is passed through any substance in gaseous, liquid or solid state, the light scattered at right angles contains radiations not only of the original frequency (Rayleigh Scattering)  but also of some other frequencies which are generally lower but occasionally higher than the frequency of the incident light. The phenomenon of scattering of light by a…

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Radioactive Pollution

What is Radioactive Pollution? Radioactive Substances and nuclear radiations (i.e., alpha, beta & gamma-particles) produced during nuclear reactions, affect our environment adversely and thus radioactive pollution is created. Sources of Radioactive Pollution Low level radioactive liquid wastes, radioactive gaseous wastes & dusts are released during nuclear explosions. Effects of Radioactive Pollution I. The radioactive gaseous wastes are injected into the upper layer of atmosphere where, due to cooling they condense to fine-dust particles and thus Radioactive Cloud is formed. This…

Top 5 Chemists Killed or Injured by their Experiments

Karl Scheele Died while testing his discoveries Scheele was a brilliant pharmaceutical chemist who discovered many chemical elements-Oxygen, Molybdenum, Tungsten, Manganese and Chlorine. He also discovered a process very similar to pasteurization. Scheele had the habit of taste testing his discoveries and, fortunately, managed to survive his taste-test of hydrogen cyanide HCN. But alas, his luck was to run out: he died of symptoms strongly resembling mercury poisoning.   Robert Bunsen Blinded himself in one eye Robert Bunsen is probably…

Planet-519937_1280

Entropy and Disorder

In science, we look for patterns to discover nature's laws. What is the pattern common to all spontaneous changes? To find a pattern, it is often best to start with very simple examples, because then the pattern is likely to be more obvious. So let's think about two simple spontaneous changes -- the cooling of a hot metal and the expansion of a gas -- at a molecular level and search for their common feature. https://www.youtube.com/watch?v=ZsY4WcQOrfk A hot block of…