August 30, 2013

Physical Chemistry – Overview of Thermodynamics

In one example I use bond energies to calculate the energy per mole of sucrose and TNT (the explosive trinitrotoluene). Most students expect that TNT has more energy, but it turns out the two have about the same. So why is TNT an explosive (actually a conflagration)? TNT burns rapidly and involves a huge volume change. It is the rate of reaction (chemical kinetics) and the rapid volume change that causes the explosive damage. Then I can move to the thermodynamics overview.
August 6, 2013

Physical Chemistry—hotness and coldness

When I start into heat capacity I contrast the temperature of a substance with the feeling of hot and cold. A thermometer will tell you the temperature of a substance, but that does not tell you how much heat is present. If you touch something, you can tell if it is hotter or colder than your hand, but what about two substances at the same temperature? Suppose outside it is -10 C (14 F) and there you find a piece of steel and a piece of Styrofoam. Which is colder? If you touch the steel it feels colder than the Styrofoam, but they are both at the same temperature. If you placed the steel on the Styrofoam, no heat will flow between them (Third Law of thermodynamics). Since your hand is much hotter than the objects, heat must flow from your hand into them.
August 2, 2013

Teaching physical chemistry–lecture recording?

Although the obvious "pro" of recording is to give students the chance to listen numerous times; review the material; and listen to missed lectures, there is a huge "con" and that is they skip class and opt to listen to my lectures at home. Last year the attendance dropped to half because lectures are available on line, but this year the time has been shifted to 8:30 a.m. from 10:30. I am going to predict that very few will want to attend at that hour.
July 25, 2013

Physical chemistry-Where is chemical energy stored?

One question I pose every year to my physical chemistry class of life science students in the first lecture is “Where is chemical energy stored?” Almost all of them say in chemical bonds. Ask how the energy is released, and they say “When bonds are broken.” Wrong!
January 28, 2013

Seminar: A local realistic reconciliation of the EPR paradox–Part 1 Video

Local realism is heresy
July 3, 2012

Complementarity between spin components in quantum mechanics

This example nicely shows several things about quantum mechanics. First quantum mechanics is a statistical theory of measurement. You only get the SG results after many spins have been filtered. Second, Heisenberg’s uncertainty relations tell us that you cannot devise an experiment that will measure both the Z and X polarization simultaneously. You can do it for one, but not the other, and vice versa.
June 4, 2012

Physical chemistry course outline on intrinsic spin angular momentum.

The lectures will be recorded at the Indian Institute of Technology (IIT) Madras which is part of the NPTEL program. A major goal of NPTEL is to raise awareness and improve scientific and technological education throughout India by use of multimedia. I will be giving a series of lectures on basic spin theory for chemistry and physics undergraduate students who have a basis in quantum mechanics; know of spin and its importance; and want to go deeper.
December 19, 2011

Entropy (Part 6): Randomness and ensembles

httpvh://youtu.be/wFe2zu2116I After rolling 2, 3, 4, 10 and Avogadro’s dice, as seen in the entries below, it becomes clear that the most random states (most number of ways of rolling a number) always dominate while those with fewer arrangements occur less frequently: 1 Entropy: Randomness by rolling two dice 2 […]
December 14, 2011

Exams: Teach yourself to learn.

A “course” is a “path” through the material which your prof. decides is important and attempts to teach you. Exams come from that material, so listen to him/her. You need to organize that material, see how it fits in the big picture and manage your time properly: that is you must be efficient.
December 12, 2011

Entropy (Part 5): Randomness by rolling Avogadro’s dice

With Avogadro's number of dice, you can roll them as much as you want, and the chance that there is an outcome other than the one that corresponds to the position of the spike is so unlikely you can safely ignore them.
December 8, 2011

Is Learning Chemistry difficult? Are you stressed about it?

Exam time is coming and we have 1,100 freshman chemists getting stressed and nervous, so this is for them. You need “stress” in your live. No stress would mean you would stay in bed all day. Well I’m a chemistry prof and like physical chemistry, and not a psychologist, but over the years you get to know students worries. There are two types of stress. There is bad stress ("I'm scared", "I'm dumb" "It is too hard?") and there is good stress ("Great day, gotta get up!", "I really want to understand stuff" "I am looking forward to tonight, so got to look good.") Use the good stress.
December 5, 2011

Entropy (Part 4): Randomness by rolling ten dice

For 10 dice there are over 60 million arrangements and Figure 1 shows the outcomes for 30,000 rolls.

Email Subscriber !

Signup now and receive and email once I publish new content.

Loading