IYC2011 - Oxygen Mystery Cache
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Difficulty:
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Terrain:
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Size: 
(micro)
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This is a cache in the IYC2011-series that is preparing for
the
International Year of Chemistry in 2011. They will
hopefully
increase chemistry knowledge as well as provide for good
cache
experiences.
Each cache in the IYC2011-series contains a clue (on the
log
sheet) to find the final IYC2011-cache to be released on
1/1/2011.
Oxygen
Oxygen is represented by the symbol O and with atomic number
8.
It is a member of the chalcogen group on the periodic table, and is
a highly reactive nonmetallic period 2 element that readily forms
compounds (notably oxides) with almost all other elements. At
standard temperature and pressure two atoms of the element bind to
form dioxygen, a colorless, odorless, tasteless diatomic gas with
the formula O2. Oxygen is the third most abundant
element in the universe by mass after hydrogen and helium and the
most abundant element by mass in the Earth's crust. Diatomic oxygen
gas constitutes 20.9% of the volume of air.
All major classes of structural molecules in living organisms, such
as proteins, carbohydrates, and fats, contain oxygen, as do the
major inorganic compounds that comprise animal shells, teeth, and
bone. Oxygen in the form of O2 is produced from water by
cyanobacteria, algae and plants during photosynthesis and is used
in cellular respiration for all complex life. Oxygen is toxic to
obligately anaerobic organisms, which were the dominant form of
early life on Earth until O2 began to accumulate in the
atmosphere 2.5 billion years ago. Another form (allotrope) of
oxygen, ozone (O3), helps protect the biosphere from
ultraviolet radiation with the high-altitude ozone layer, but is a
pollutant near the surface where it is a by-product of smog.
Water (H2O) is the oxide of hydrogen and the most
familiar oxygen compound. Hydrogen atoms are covalently bonded to
oxygen in a water molecule but also have an additional attraction
(about 23.3 kJ·mol-1 per hydrogen atom) to an
adjacent oxygen atom in a separate molecule. These hydrogen bonds
between water molecules hold them approximately 15% closer than
what would be expected in a simple liquid with just van der Waals
forces.
For reasons of economy, oxygen is often transported in bulk as a
liquid in specially insulated tankers, since one litre of liquefied
oxygen is equivalent to 840 liters of gaseous oxygen at atmospheric
pressure and 20 °C. Such tankers are used to refill bulk liquid
oxygen storage containers, which stand outside hospitals and other
institutions with a need for large volumes of pure oxygen
gas.
Highly enriched [18O]H2O, with enrichment
>95%, is used as target material in cyclotrons for the
production of the positron emitter18F for PET-imaging.
Read more about Oxygen here or here.
The coordinates
N 60° AB. CDE
E 005° FG. HIJ
A:Oxidation state of O in oxygen difluoride
(OF2).
B:Number of electrons in the K-shell.
C:Number of atoms in ozone.
D:Number of oxygen atoms in glucose.
E:Number of neutrons in 15O.
F:Half-life of the most stable radioisotope of oxygen, in
minutes.
G:Number of oxygen atoms in acetone.
H:Phases of solid oxygen known to exist.
I:Number of oxygen atoms in phosphate.
J:Number of electrons in the L-shell.
Cache contents
- Logsheet
- Pencil
- FTF-certificate
Additional Hints
(Decrypt)
Fvta.
Zntargvp