Home' Trinidad and Tobago Guardian : June 15th 2015 Contents Guardian www.guardian.co.tt Monday, June 15, 2015
52. The word "carbon" is of what origin?
53. Charcoal is a by-product of
B. Wood or other organic substances
C. Rotting lumber
D. Filtered gasses
54. What is the benefit of using charcoal over wood?
A. It is emits less toxicity into the atmosphere
B. It is more affordable
C. It is readily available
D. It burns at a slower rate
55. What happens when charcoal is heated?
A. It becomes sturdy
B. The moisture vaporizes
C. It becomes brittle
D. Its absorption capacity increases
56. What is Activated Carbon?
A. Carbon is a process involving gas which
causes it to become porous and results in
B. Essentially just pure carbons
C. Activated charcoal that has increased in
surface area making it more porous.
D. Carbon which has been filtered into gas.
57. "Green" as used to distinguish charcoal and acti-
vated charcoal gets its name from
A. The process by which it is manufactured
B. The combination of substances used in its
C. It is free from toxic chemicals
D. It is made in a safe environment
58. The word "diverse" as used in (paragraph 12)
means the same as
59. According to claims made by the writer, activated
A. Is used medicinally, domestically, commercially
B. Has a singular use
C. Has Many uses
D. Is used commercially
60. What technique does the writer use to emphasise
the benefits of carbon and activated carbon.
END OF ENGLISH TEST
a very low electrical conductivity, but the carbon atoms are so arranged that it is among the hardest materials known. To
date carbon is known to form 10 million pure "organic" compounds, from solids (such as pure graphite or diamond) to gas or
liquid compounds such as carbon dioxide (CO2) or carbon tetrachloride (CCl4).
Carbon is what divides the world of chemistry into "organic" and "non-organic". Any compound that contains as little as one
carbon atom sets itself firmly within the camp of Organic Chemistry. But being an "organic" compound does not mean that
something is "organic" in the more common sense of environmentally "safe", or biologically more nutritious, or medicinally
Then there is charcoal. Charcoal, activated charcoal, activated carbon, or activated bio char do distinguish themselves as being
the "green" of the green, the quintessential of "SAFE". Except for specially sensitized activated carbons with otherwise toxic
substances for specific industrial or pharmaceutical uses, plain charcoal remains an FDA Category I "Safe & Effective" product
for the treatment of poisoning, and is GRAS (Generally Recognized As Safe).
"Charcoal" definition: a black or dark gray form of carbon, produced by heating wood or another organic substance in an en-
closed space without air. (Encarta World English Dictionary© 1999)
Having looked at carbon as a building block, let's look at what makes charcoal so distinct from the other forms of pure carbon.
Irrespective of what the source is for charcoal, the carbon structure has been so altered from its original configuration as to
present an extremely intricate and extremely porous internal matrix, giving it a large surface area available for adsorption
("adsorption" - the ability to bind atoms/molecules to a surface), or chemical reactions.
Historically charcoal has been made from wood, both softwoods and hardwoods. Charcoal's first application (circa 1750 B.C.)
was as a fuel for smelting ore. Charcoal burns hotter and cleaner than wood and so wood was converted to charcoal. Charcoal
was originally made basically the same way it is made today around the world.
Great piles of wood are carefully arranged above or below ground so that once the fire is set the heat that is generated slowly
"bakes" the wood, vaporizing off the moisture, vaporizing off volatile organic compounds (VOCs) leaving behind the hard
black crusted charcoal.
Historically charcoal was used for much more than cooking and smelting ore. It was used to preserve lumber from rotting,
bodies from decomposing when buried, preserving food and water on long sea voyages, making glass, controlling odours,
and as a powerful medicinal.
Charcoal is not "activated charcoal"; rather it is one raw material for the manufacture of activated carbons.
Activated Charcoal / Carbon
Activated charcoal/carbon is usually derived from charcoal or coal. There are two basic activation processes.
1. Charcoal is once again heated to very high temperatures (usually in the temperature range of 600 -- 1200 C)
in the presence of oxidizing gases such a CO2, steam, or air.
2. Charcoal is impregnated with chemicals such as acids like phosphoric acid or bases like potassium hydroxide,
or salts like zinc chloride, and then exposed to temperatures in the range of 450-900 C.
Both processes further erode the charcoal's internal surfaces. This increases the adsorption capacity by creating an internal
network of even smaller pores rendering it two to three times as effective as regular charcoal. But activated charcoal is not
produced from wood alone. While coal is not charcoal, coal may be the largest source for the manufacture of activated char-
coals. Other sources include wood, sawdust / saw chip, coconut shells, bamboo, peat and petroleum coke, which are the most
common starting materials for making activated charcoal. Many other materials have been experimented with, but generally
are not as economical, at least not until recently.
As diverse as carbon is in the chemical world, just so is the diversity of activated charcoal in its applications. One activated
charcoal manufacturing company logo goes "A thousand applications today, a thousand and one tomorrow". It might also be
said of charcoal "Imagine the Possibilities".
In review, we drink water filtered by it; breath air scrubbed with it; eat food purified through it, wear clothes made with it;
grow our food and flowers in it; go to war with it; preserve things in it; enjoy hundreds of dishes cooked by it; we move moun-
tains with it; we make the night sky sparkle with it; we take it with us to the bottom of the deepest oceans and out into
space; swim in water washed with it; paint or draw our inspirations with it; and we record man's history of successes and
mistakes dipped in it. Not least and not last, charcoal is called upon to clean up many of our technological mistakes. No wonder
we naturally warm up to it.
(Source: www.buyactivatedcharcoal.com/what_is_activated_charcoal) (Edited)
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