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THE FINE PRINT (TEDIOUS DETAILS) Click here to return to the dictionary |
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ethanol |
A member
of the alcohol homologous series (general
formula R-OH, pronounced ‘rho’) found in
teachers’ bottles of ‘water’ the world over.
Ethanol dissolves easily in water because a large percentage of the
molecule is polar. The very
electronegative oxygen atom pulls the electrons in the O-H bond towards it,
causing a negative end (O) and a positive end (H) to form. The intermolecular force created by
positive ends on one molecule pulling in negative ends on neighbouring
molecules is called hydrogen bonding. Water
itself is highly polar, because it is essentially
two OH groups in one place at the same time.
Polar molecules mix fully with other polar molecules, like a bag full
of different kinds of magnets.
Non-polar molecules mix fully with other non-polar molecules, like a
bag full of different kinds of beans.
Polar and non-polar molecules do not mix, as you can see when petrol
floats on water. They won’t mix
because the polar molecules are only attracted to each other. If you put some beans into your bag of
magnets, the beans won’t get between the magnets for very long. The beans will collect at the bottom. In
alcohols with much longer non-polar alkyl groups, the polar effect of the –OH
group is unnoticeable and their physical properties are closer to non-polar
hydrocarbons than short-chain alcohols.
Alcohols with more than one –OH group are called polyhydric
alcohols. A good example is the
trihydric alcohol propane-1,2,3-triol AKA glycerol
or bubble mixture. Drunkenness and genetics Molecular
formula C2H5OH, ethanol was originally mixed with
drinks in Help I’ve been affected by ethanol Ethanol is
a sexual catalyst because it makes sex possible at lower levels of attraction
than normal. Although chemistry
constantly talks about how catalysts are a good thing, in this case, it’s
often not. Ethanol can make the
following reaction frighteningly feasible: you +
whale → bed The
mechanism is that ethanol inhibits your ability to say no, not only to sex
but to pretty much anything. You won’t
be able to resist fighting, eating, urinating in telephone boxes, falling
over, vomiting, karaoke or spending all your wages in Chicken Master. If you wake up with an unpleasantly high
concentration of ethanol in your body, read this
article about why you feel hung-over. If you wake up with a ho,
all I can offer you is this: you should have run while you had the chance. |
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fatty
acids |
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hydroxonium
ion |
We talk
about the concentration of H+ ions being the meaning of acidity
but in fact the protons released by acids exist as part of the hydroxonium
ion, H3O+. The
name comes from hydrogen + oxygen fitted into the pattern of ammonium NH4+, the
ion formed when ammonia, NH3, uses its nitrogen atom’s lone pair
to form a dative-covalent bond with an H+ ion. The chemistry of H+ compared to
H3O+ is exactly the same. The H2O that bonds to the H+
is just hydrating it, like water ligands hydrate Cu2+ ions to make
a complex that causes the truly excellent blue colour of copper(II) sulphate.
As soon as you want your H+ to do something chemical, like
react with an |
How do
you name hydrocarbons? What does octane
mean?
Firstly, the
oct- prefix indicates an eight-carbon atom
skeleton. Secondly, the –ane suffix indicates the chemical is a member of the alkane
homologous series. This implies a
molecular formula CnH2n+2, where n is the number of
carbon atoms present. I know n = 8 from
the name, so the formula must be C8H2x8+2 = C8H18
General formula for alkanes: CnH2n+2
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Sodium
isn’t spelt with N or A, so why is its symbol Na?
Most of the elements have easy-to-understand symbols. Lithium’s symbol Li comes from the first two
letters of its name. Confusingly, some
elements have symbols made of letters that don’t appear in their names at
all. Here’s why…
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Symbol |
Element |
Why? |
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Ag |
Silver |
Argentum is Latin for silver |
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Au |
Gold |
Aurum is Latin for gold |
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Cu |
Copper |
Cuprum is
Latin for copper |
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Fe |
Iron |
Ferrum is Latin for iron |
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Hg |
Mercury |
Hydrargyrum is Latin for mercury |
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K |
Potassium |
Kalium is Latin for potassium |
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Na |
Sodium |
Natrium is Latin for sodium |
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Pb |
Lead |
Plumbum is Latin for lead |
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Sb |
Antimony |
Stibnum is Latin for antimony |
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Sn |
Tin |
Stannum is Latin for tin |
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W |
Tungsten |
Wolframium is Latin for tungsten |
Where
do they get the names for elements and chemicals from?
Let’s face it, the origin of words like oxygen isn’t exactly
obvious. For other elements (e.g.
Einsteinium), it doesn’t take a genius to see where the name came from, but you
still wonder why that one got that
name. I only know a few but if I find
out more I’ll keep you posted.
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Symbol |
Element / Chemical |
Who came up with that? |
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Mg |
Magnesium |
Magnesia
was a place in |
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NH3 |
Ammonia |
Ammonia
gets its name from sal ammoniac, an outdated word for
ammonium chloride NH4Cl.
The name came from sal ammoniacus, Latin for ‘salt of Ammon’. The word ammoniacus came into the Latin
vocabulary from Greek, in the form of the Greek word ammōniakos (αμμωνιακος),
meaning ‘of Ammon’. What’s Ammon and why is ammonium chloride named after it, you
ask? The salt found by the Greeks near
the |
Pseudo-element
symbols
Sometimes you’ll see symbols for what seem to be elements that aren’t
on the periodic table alongside the normal elements. It’s sometimes appropriate to abbreviate very
common molecules to a symbol, especially for organic groups and ligands. These symbols are often called
pseudo-elements.
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Symbol |
Pseudo-element |
Structural formula |
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D |
Deuterium (hydrogen with an extra
neutron) |
2H |
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acac |
Acetylacetone
(2,4-pentadione) (a ligand) click orange text for
MSDS |
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en |
Ethylene diamine
(= ethane-1,2-diamine) |
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Et |
Ethyl group |
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Me |
Methyl group |
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PR3 |
Trialkylphosphine group |
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Ph |
Phenyl group |
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PPh3 |
Triphenylphosphine |
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T |
Tritium (hydrogen with two extra
neutrons) |
3H |
Specially-named
groups in the periodic table
1. The
Alkali Metals
Group 1: Li, Na, K, Rb, Cs, Fr
Form
alkaline solutions when they dissolve in water
2. The
Alkaline-Earth Metals
Group 2: Beryllium (Be), Magnesium (Mg),
Calcium (Ca), Strontium (Sr), Barium (Ba) and Radium
(Ra)
5. The Pnictogens
Group 5: Nitrogen (N), Phosphorus
(P), Arsenic (As), Antimony (Sb) and Bismuth (Bi).
Highly
reactive elements, often poisonous to humans.
6. The Chalcogens
Group 6: O, S, Se, Te,
Strongly
oxidising, electronegative elements
7. The
Halogens
Group 7: Fluorine (F), Chlorine (Cl),
Bromine (Br), Iodine (I) and Astatine (At).
Highly
reactive electronegative diatomic molecules, ranging from gas to liquid to
solid at room temperature.
8. The
Noble Gases
Group 8: Ne,
Ar, Kr, Xe, Rn
Extremely
unreactive monatomic gases
Look
Around You
This website is funny: www.bbc.co.uk/comedy/lookaroundyou.
Chucklesome gags on the DVD include “…water, chemical symbol H-twenty, is the giver of life.”