Data Safety Sheet for Water

water molecule

H2O

From Kausik Datta at In Sciento Veritas over on SciLogs we have a bit of nerdish humour: The Material Data Safety Sheet for hydrogen hydroxide, or was that dihydrogen monoxide?

Simple organic compounds: alkanes

Methane (1 carbon), ethane (2 carbons)

In the previous post, I casually mentioned methane and ethane in the atmosphere of Saturn’s moon Titan. I’ve started with the terms in that post and worked back to the supporting concepts so you can read until you get to things you already know.

  • Methane and ethane are the simplest hydrocarbons.
  • Hydrocarbons are molecules that are comprised entirely of atoms of hydrogen and carbon. Specifically, they have no oxygen, which is the commonest other component of organic molecules.
    • Incidentally, a molecule that contains hydrogen, carbon, and oxygen is a carbohydrate, a completely different kind of molecule. In his book Chariots of the Gods, Emmanuel Velikovsky casually changed hydrocarbons (fuel) into carbohydrates (food) with a twist of the typewriter, demonstrating that he knew nothing about chemistry.
  • Organic molecules contain carbon and are more complex than carbon dioxide (CO2). They’re called organic because a hundred years ago, we thought that only biological processes could form them: that’s all that scientists had ever observed. Since then, we have learned to synthesize them step by step, observed them forming from inorganic compounds, and detected them in interstellar clouds. The chemistry of carbon is called organic chemistry.
  • The smallest alkane is methane, with one carbon. Ethane has two, propane has three, butane has four. After that they use Greek numeric prefixes pentane, hexane, heptane, octane, and so on.
  • Alkanes are saturated hydrocarbons: saturated means that every available bond is filled: the molecule is saturated with hydrogen and cannot take up any more. There are no double bonds on any of the carbon atoms in an alkane. They are sometimes said to have a carbon “backbone.” You can read more about alkanes. Hydrogen atoms tend to clutter up chemical structure diagrams, so they are often left out: just assume that a hydrogen atom fills every unspecified bond.
  • Carbon atoms can form four covalent (electron-sharing) bonds, so each carbon atom can connect to four other atoms. This is the secret to its success in building large, even gigantic molecules and why we think that other life might be “carbon-based.”
Tetrahedral structure of methane

Methane

  • The carbon bonds naturally radiate to the four tips of a triangular pyramid with the nucleus in the centre: carbon molecules are not flat. Methane is a tetrahedral molecule. molecules with carbon chains are, at the very least, crinkled. Thus, even the simple structure of a three-carbon molecule has two conformations, with the ends of the molecule bent towards or away from each other.

Carbon molecules showing "handedness"

  • If a carbon atom has different atoms attached to its bonds, it can form a molecule with mirror image versions like left-handed or right-handed mittens. No matter which way you turn them, you can’t superimpose them. This is called chirality (handedness) and the molecules are called enantiomers of each other.
  • Carbon has 6 protons in its nucleus; otherwise, it would be something else: the number of protons defines the element. If the nucleus has more or fewer neutrons, it’s an isotope of the element. A carbon atom usually has 6 neutrons but there’s an isotope with 8 neutrons, which is slightly less stable and decays over time. [Corrected as noted below.]
  • An atom has a nucleus surrounded by electrons. A nucleus is built of protons (positive charge) and neutrons (no charge) surrounded at some distance by electrons with negative charge.

Old wine in new bottles

This is what consultants sell: the same old thing, with new, expensive trappings: “Want to make an amide? Have I got good news for you!

Yep, that’s right: someone has come up with a new way to form amides by reacting acid chlorides and amines. “But hold on,” you say, “I thought that acid chlorides and amines form amides like an unstoppable juggernaut, which grinds to a halt only when enough HCl is given off to take the remaining amine out of contention”.

Periodic table of videos

The University of Nottingham in England is producing a series of short science videos about chemical subjects.

Because of the recent, unusual amount of snow in the U.K. they have made one about snow:

[Youtube=http://www.youtube.com/watch?v=wuPTPUkTQ7s]

Here’s the “periodic table of videos” index.

Periodic table of videos

The University of Nottingham has a Periodic Table of Videos.

Hat tip to Primaklima:Klicken statt Büffeln: Das Periodensystem.”

Wer, wie ich, chronische Schwierigkeiten mit der Chemie hatte und hat, dem kann jetzt geholfen werden. Die Universität Nottingham hat das gesamte Periodensystem verfilmt. Einfach das Element anklicken und in einem 5 Minuten Videostrip wird einem alles mitgeteilt, was man zu einem so interessanten Element wie Ununpentium immer schon mal wissen wollte.

Periodic table of science videos

Periodic table of science videos

Did you celebrate Mole Day?

I just learned of another nerdy holiday: Mole Day is celebrated by chemists as an analog of Avogadro’s Number, the number of molecules in a mole of matter. It’s 6.023 x 10^23, so the holiday runs approximately from 6:02 a.m. to 6:02 p.m. on October 23.

Discoverer of GFP gene misses out on Nobel prize

A cat with jellyfish genes glows in the dark.

Glow in the dark cats

(more funny cat pictures)

The science-journalism tracker described predictions about who would win the chemistry prize. One chemistry professor cum science writer got it 2/3 right: Osamu Shimomura and Roger Tsien for Green Fluorescent Protein, which allows geneticists to track patterns of gene activity.

At the bottom of the article is a sad note:

And finally, DO NOT MISS NPR’s Morning Edition program today, by Dan Charles. He tracked down and interviewed the man who isolated the key jellyfish protein gene, suspected it to be a potentially powerful bio tracer, and provided samples to Chalfie and to Tsien. His science funding dried up. The man now is driving a shuttle bus for an Alabama auto dealership.

The three winners of the Nobel Prize for chemistry are Martin Chalfie of Columbia University, New York City; Osamu Shimomura, a Japanese citizen who works at the Marine Biological Laboratory in Woods Hole, Massachusetts; and Roger Tsien of the University of California, San Diego.

Chalfie, O Shimura, Roger Tsien

Nobel Prize for Chemistry: Martin Chalfie, Osamu Shimura, Roger Tsien

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