Chemistry
worldsfair | May 24, 2007"Intermolecular forces are the forces between molecules, whereas intramolecular forces are those within molecules. (The bonds that hold the atoms in a molecule together are intramolecular forces.) A quick note before we jump in: When chemical educators are explaining intermolecular forces, they almost always use examples of intermolecular attractions..."
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worldsfair | May 24, 2007"When multiple atoms are part of an assembly in which they are bonded to each other, you have a molecule. For the moment, consider the "bond" between atoms in a molecule to be an electron-sharing arrangement that maintains a certain (average) spatial configuration between the nuclei of the bonded atoms..."
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worldsfair | May 24, 2007"An element is defined by the number of protons in the nucleus. The element oxygen has 8 protons in the nuclei of its atoms. Any atom (or radical or ion) that has exactly 8 protons is an oxygen atom, and all oxygen atoms (or radicals or ions) have exactly 8 protons. It doesn't matter how many electrons there are zipping around the nucleus; that determines the net charge.."
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terrasig | May 9, 2007Via the Knight Science Journalism Tracker at MIT, I was directed to one of the best-written articles on melamine contamination of pet food and animal feed.
David Brown at the Washington Post is the guilty party whose article appeared Monday. Brown does a terrific job of explaining how the modestly toxic substance, melamine, can cause renal failure when combined with cyanuric acid. Not widely reported in the press is the fact that cyanuric acid, another nitrogen-rich compound, has also been found to contaminate some wheat gluten and wheat flour from China.
For example, here is the most…
jstemwedel | April 24, 2007The April 16 issue of Chemical & Engineering News has an interesting article about homeschooling families looking for chemistry curricula. (You need an individual or institutional subscription to view the article; it might be worth checking with your local library.)
I'm far from an expert on homeschooling (as we're availing ourselves of the public schools), but I'm fascinated by the ways some of the families featured in the article are piecing together what they need for their kids.
Why families choose to homeschool is an interesting question. From the article,
One common reason [to…
retrospectacle | April 24, 2007
Yes, someone tested out the caffeine soap and blogged the results!
Seems like he felt a bit of a buzz, however whether its caffeine or a bit of the placebo effect, well who can say.
I jumped into the shower and lathered up with the Shower Shock. Now, in addition to containing roughly 2400mg of caffeine, each bar is also heavily loaded with peppermint oil. Not long after lathering up, I got the feeling that not only had I just gone for a brisk stroll in the peppermint rain through the peppermint forest of the children's board game "Candyland," but while walking through the forest I had…
retrospectacle | April 24, 2007 From the BBC on down, in the past few days the headline "Alchohol Makes Fruit Healthier" has been highlighted in nearly every news venue.
The fruit contains compounds [antioxidants] that can protect against cancer, heart disease and arthritis.
But having them with alcohol, such as in a daiquiri, boosts these antioxidant properties, the Journal of the Science of Food and Agriculture says.
Nutritionists said the "detrimental effects" of such drinks could cancel out such benefits.
As a college student, no one takes this sort of study more seriously than I. Alcohol as health food? Surely you…
retrospectacle | April 20, 2007One reason that treatments for the human immunodeficiency virus (HIV) are particularly difficult to develop is that HIV is quite good at adapting resistance to drugs. Many of the virus' surface proteins--natural targets for inhibitory drugs--have a high turnover rate and are easily changed. There are a few exceptions; a few well-conserved surface proteins that are integral to HIV's function. One of these is the protein gp41 (below), which is required for HIV to attach onto a host cell, and infect it.
However, a recent paper in Cell describes a naturally-occurring blood molecule called VIRIP…
ksharpe | April 3, 2007Hello, and welcome to the Sweet Sixteen round of the Science Spring Showdown—ScienceBlogs' answer to March Madness. (Feeling confused? Catch yourself up on what this is all about, here). The phrase "Mad as a March Hatter" might be apposite. But be that as it may, Page 3.14 is nothing short of delighted to host the penultimate match in the Mortar and Pestle Division. The action happens right here, folks. You are basically sitting in courtside seats. The rivalry goes down on Friday. For now, sit back and enjoy the Pre-Game Hoopla!
This Friday, fans will return to Chemical Arena, where Fossil…
jstemwedel | March 30, 2007The pregame show has already started on the Acid vs d-orbitals game, but we've just received another set of predictions about this game and the Fossil Fuels vs. Erlenmeyer Flask match (hmm, should I say "match" there?) from the Molecule of the Day guy. Adjust your best accordingly!
Acid vs d-orbitals:
I have to agree with Derek Lowe - d orbitals for sheer utility. They inform huge swaths of chemical usefulness, notably in the case of metal catalysts. Acids might pull ahead for reasons of recognition, and the second row of the periodic table might be more comfortable territory to relative…
jstemwedel | March 29, 2007You've been waiting patiently. It's almost here!
PRESS CENTER | UPDATED BRACKET
GAMES TO BE PLAYED NEXT WEEK (April 2nd to 6th, 2007)
While the first two rounds of chemistry play were hosted here, Acid vs. d-orbitals will be hosted by The World's Fair and Fossil fuels vs. Erlenmeyer flask will be hosted by Page 3.14. (If you haven't already, check out the pre-game prognostication here and here. I heard a rumor that more is on the way.)
Next week, it's time for me to put on my philosophy of science hat and cover (with Ben Cohen) the Kuhn vs. Theory game, to be hosted right here.
Other…
evolvingthoughts | March 28, 2007
Here is a list of Basic Concept posts in Chemistry.
Recently Added:
Inorganic
pH by Cat at Lab Cat
Strong and Weak Acids by Cat at Lab Cat
Acids and Bases by Cat at Lab Cat
Elements by Janet Stemwedel at Adventures in Ethics and Science
Polar and Non-polar Molecules by Janet Stemwedel at Adventures in Ethics and Science
Intermolecular Forces by Janet Stemwedel at Adventures in Ethics and Science
Organic
What is Food Science? by Cat at Lab Cat
Food Chemistry by Cat at Lab Cat
terrasig | March 27, 2007A few years ago, GlaxoSmithKline marketed Remifemin brand of black cohosh extract from their consumer products division as a hormone-free alternative in managing menopausal symptoms. But after reports surfaced that black cohosh might be associated with cases of liver damage, GSK very quietly walked away. (To date, no one has ever shown that black cohosh is causally associated with liver damage). A company called Enzymatic Therapy continues to sell this product in the US, one that is manufactured by Schaper & Bruemmer in Germany.
Well, here's what happens when GSK gets involved in…
jstemwedel | March 26, 2007As we head into the Science Spring Showdown Sweet Sixteen, it seemed prudent to turn to some experts for their predictions on the two remaining games in the chemistry region, Acid vs. d-orbitals and Fossil fuels vs. Erlenmeyer flask. (Of course, we won't soon forget the exciting first and second round games that brought these four teams to the Sweet Sixteen.)
Here's what some members of the chemical cognoscenti have to say:
Acid vs. d-orbitals:
While professing not really to understand the American basketballesque nature of the tournament, Propter Doc was willing to call this one as follows…
jstemwedel | March 20, 20071st ROUND RESULTS | PRESS CENTER | PRINTABLE BRACKETS
Welcome to coverage of the 2007 Science Spring Showdown second round play in the Chemistry region. The fans in Chemical Arena resorted to a face centered cubic strategy to pack themselves into the stands. You could almost feel the electricity in the air as the products of the first round match-ups were poured into the separatory funnel of the second round. The fans and the teams shook things up. Which teams came out in the top layer, and which saw their hopes of going all the way drained out?
Acid: 105Ethanol: 87
In one of the most…
terrasig | March 20, 2007So say the American elder statesmen of natural products in the 2007 update of their periodic review of the subject to be published in the 23 March issue of the Journal of Natural Products. (Details are in this Reuters article with by Julie Steenhuysen). I will post more about the article when I get my hands on it, but it comes from NCI's Dr David Newman and recently-retired Dr Gordon Cragg. Cragg had led the NCI Natural Products Branch, a position that Newman now holds.
Newman and colleague Gordon Cragg reviewed the origins of new drugs developed in the past quarter-century and found that…
jstemwedel | March 19, 2007PRESS CENTER | PRINTABLE BRACKETS
Even given a weekend to come back to equilibrium, some chemistry fans are still perturbed by some of the results of first round play in the MORTAR AND PESTLE bracket. FTIR's upset win over NMR has many a Monday morning spectroscopist splitting his peaks trying to analyze what went wrong. And while Ethanol is a perennial powerhouse in this conference, many tournament watchers had anticipated celebrating Caffeine at their Monday morning lab meetings.
Friday's games were just the first step in a mutli-step synthesis of a tournament champion. Tomorrow, just…
jstemwedel | March 16, 2007PRESS CENTER | PRINTABLE BRACKETS
The March weather in California has taken a turn for the beautiful this afternoon, but to chemistry conference fans, the natural beauty of the great outdoors is no match for the beauty of the competitions inside the Chemical Arena. The crowds donned their safety goggles and souvenir nitrile gloves and piled in to observe the action. The press box was a flurry of strip-charts and lab notebooks. After some excited play, here are the first round results:
Entropy: 117Enthalpy: 84
While Entropy was the favorite of the odds makers going into this game, Enthalpy'…
jstemwedel | March 14, 2007PRESS CENTER | PRINTABLE BRACKETS
It's time for a quick run down of the teams from the Chemistry Conference who made it to the tournament this Spring -- some who we fully expected to see here, and a few surprises. But it's also time for you, the fans, to make some noise in support of your favorite teams! If we follow your observations on these competitors down to the quantum level, they're bound to effect the outcome (albeit in a probabilistic way).
Here are the first round match ups:
Acid vs. Base: It's not a surprise to find these teams here, as they're standbys in the Chemistry…
jstemwedel | March 10, 2007As promised at the end of my post on polar and non-polar molecules, here's a basic concepts post on intermolecular forces. Intermolecular forces are the forces between molecules, whereas intramolecular forces are those within molecules. (The bonds that hold the atoms in a molecule together are intramolecular forces.)
A quick note before we jump in: When chemical educators are explaining intermolecular forces, they almost always use examples of intermolecular attractions. You could just as easily talk about intermolecular repulsions (which are forces too, after all), but it's the…