Download 8.TT.1.3 Arsenic PowerPoint

8.TT.1.3 Arsenic
PowerPoint
By: Maleek Walker
Chemistry Exit Project
Arsenic Background
• Arsenic is a naturally occurring substance. It
occurs in several forms, often in compounds
with other chemical elements. Arsenic and all
of its compounds are poisonous but the
toxicity varies. For example, inorganic arsenic
- arsenic combined with oxygen, chlorine or
sulfur - is thought to be the most toxic, while
most organic forms of arsenic are relatively
less toxic. In its solid state arsenic appears
as a silver-gray, brittle semi-metal that
tarnishes in the air. It is about the 52nd most
common chemical element on the earth.
Where Is Arsenic Found?
• Since arsenic can be produced from its
ores very easily, many early craftspeople
may have seen the element without
realizing what it was. It was first
recognized as an element by alchemists.
Although it is not certain where and when
arsenic was actually discovered, credit for
the discovery usually goes to alchemist
Albert the Great (Albertus Magnus, 11931280).
Arsenic In Everyday Life
•
The most widely known use of arsenic is as a poison. It is
used in bug, weed, and rat poisons. It is also highly toxic to
humans and can cause cancer when it comes in contact with
humans. If ingested in small amounts over time, it will produce
the symptoms of pneumonia and the victim will die with hardly
a trace Of arsenic in his body. Coroners today have ways of
detecting the smallest amounts in an autopsy, so arsenic is
rarely used for poisoning people anymore. It was discovered
that Napoleon Bonaparte might have died from arsenic
poisoning. Massive amounts of arsenic were found in his hair
structure. The dye in the wallpaper of his room large amounts
of arsenic, and the damp may have created a deadly gas which
he inhaled.
Properties In Arsenic
• The element is a steel gray, very brittle,
crystalline, semimetallic solid; it tarnishes
in air, and when it is heated it rapidly
oxidizes to arsenous oxide, which smells
of garlic. Elemental arsenic occurs in two
solid modifications: yellow, and gray or
metallic, with specific gravities of 1.97, and
5.73, respectively. Arsenic and its
compounds are poisonous.
Interesting facts on
Arsenic
•
Interesting Facts
•
~ In its pure form, arsenic costs $320 per 100g.
•
~ Arsenic compounds were mined by the early Chinese, Greek, and Egyptian civilizations.
No doubt they discovered its toxic properties early on.
•
~ Arsenic’s name appears to derive from the Latin word arsenicum and the Greek word
arsenikos, meaning “masculine” or “male.” In earlier times it was believed that metals had
different sexes.
•
~ In 1989, the total usage of arsenic in the world was 52,380 tons of As2O3, with
approximately 28,530 tons imported by the United States. Pesticides and wood
preservatives accounted for over 80 percent of this use.
•
~ Arsenic makes up 50 ppb by weight and 4 ppb by atoms in a human being.
•
~ During the Middle Ages, arsenic compounds were often used to commit murder. At the
time, it was difficult to detect the presence of arsenic in the body, so the person who was
murdered was thought to have died of pneumonia
Arsenic Being Deadly
• Arsenic compounds are very poisonous to plants and animals. In
low doses, arsenic causes nausea, vomiting, and diarrhea. In larger
doses, it results in abnormal heartbeat, damage to blood vessels,
and a feeling of “pins and needles” in hands and feet. Small corns
or warts may begin to develop on the palms of the hands and the
soles of the feet. Direct contact with the skin can cause redness
and swelling. Long term exposure can cause cancer. Inhalation
results in lung cancer. If arsenic is swallowed, cancer may develop
in the bladder, kidneys, liver, and lungs. In large doses, arsenic can
be deadly. Despite the danger of arsenic, it is found in pesticides,
wood preservatives, and many household products.
Biological Role
• Arsenic may be a necessary ultra trace
element for humans. It is a necessary
ultra trace element for red algae, chickens,
rats, goats, and pigs. A deficiency of
arsenic results in inhibited growth.
Arsenic Sources
• It is sometimes found native, but usually
combined with silver, cobalt, nickel, iron,
antimony, or sulfur. Arsenopyrite also
called mispickel is the most common
mineral from which, on heating, the
arsenic sublimes leaving ferrous sulfide.
Arsenic Make-up
•
Symbol As
•
Atomic Number 33
•
Atomic Mass 74.9216
•
Electron Configuration [AR] 3d104s24p3
•
Density @ 293 K 5.72 g/cm3
•
Melting Point 1090 K
•
Boiling Point 886 K (sublimes)
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1st Ionization Energy 946.5 kJ/mole
•
Structure Rhombohedral
•
Atomic radius 120 pm