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Elementsthe building blocks of all matter
The most important element is probably carbon. It has
absolutely unique properties in the fact it can link to itself and form
literally billions of different chemicals. Some of them have
even become living matter. Inorganic carbon can exist as a
diamond, both very beautiful and the hardest material known.
The most beautiful element is probably Gold. It is unique in the
since it is both metallic and colorful. Unlike Copper (which can also be very beautiful), Gold does not tarnish or corrode. It is
also so soft it can be finely polished just by rubbing it.
The most fascinating element is probably Mercury. It is the only metal which is fully liquid
at room temperature. Unfortunately, unlike Carbon or Gold, Mercury is poisonous. Radium
can also bedazzle people. A concentrated solution of radium chloride glows with a soft, blue
phosphorescence. Close inspection reveals a galaxy of tiny stars twinkling throughout the
glowing liquid. However, Radium is far more dangerous than Mercury because it is so terribly
radioactive. The scientist who discovered it (Curie) eventually died of leukemia, most likely
due to radiation exposure.
The most useful element is Iron, of course. It is easy to make and
the properties of the metal can be fine tuned by alloying it with
carbon and/or other metals. The creation of the Japanese Samurai sword is a fascinating study in the
combination of high and low carbon steel into a remarkably effective and elegant weapon.
The strangest element might just be Francium. It is formed by the radioactive decay of larger atoms, but Francium itself has a half life
of only about 10 minutes. Francium exists, but only as single atoms dispersed throughout the universe which suddenly appear
like soap bubbles and then disappear just as quickly.
The most abundant element is Hydrogen. Most of the universe is made of this gas. The human
body is mostly water, and because water is 2/3 hydrogen, humans are also mostly made of hydrogen as
well.
The Elements
• 116 known elements• 94 occur naturally
-22 artificially made by nuclear processes
Properties of Metals
• Metals are good conductors of heat and electricity.
• Metals are shiny.• Metals are ductile (can be
stretched into thin wires).• Metals are malleable (can be
pounded into thin sheets).• A chemical property of metal is
its reaction with water which results in corrosion.
Properties of Non-Metals
• Non-metals are poor conductors of heat and electricity.
• Non-metals are not ductile or malleable.
• Solid non-metals are brittle and break easily.
• They are dull.• Many non-metals are
gases.Sulfur
Properties of Metalloids
• Metalloids (metal-like) have properties of both metals and non-metals.
• They are solids that can be shiny or dull.
• They conduct heat and electricity better than non-metals but not as well as metals.
• They are ductile and malleable.
Silicon
The Periodic Table
Compound
• Two or more elements chemically combined in specific proportions
• Examples:– Water H2O
– Salt NaCl
– Sugar C6H12O6
Chemical Formulas are used to represent compounds
CompoundsOrganic
• contain carbon
• produce smoke or soot when heated
-ex. Acetic acid
ascorbic acid
ethanol
propane
Inorganic• some contain carbon but
it evolve to gaseous compounds
• form white residue when heated
-ex. Water
baking soda
ammonia
hydrochloric acid
• 95% of living organisms is made of: carbon (C) oxygen (O) hydrogen (H) nitrogen (N)
Elements of Life
*water- most abundant compound*human body= 80%
Indicator- tool to classify compound
(distinct colors when mixed w/ acids, base or salt.)
•Acid
-sour
-red to blue
-colorless
(ph indicator)
•Base
-bitter
-blue to red
-purple
Classifying mixtures
Mixtures may be either:
Solutions
Colloids
Suspensions
Solutions
• Have small particles
• Are transparent (not the same as colorless)
• Do not separate
• Water solutions are very common in
biological systems
– Examples: salt water, kool-aid, air, brass, vinegar
Colloids
• Have medium size particles
• Do not separate
– Examples: fog, whipped cream, milk, cheese,
mayonnaise
*Tyndall effect- involves scattering of light by
colloidal particles
Suspensions
• Have very large particles
• Settle out (separates into layers)
– Examples: blood platelets, muddy water,
calamine lotion, oil & water, Italian salad
dressing
Separating mixtures
• Filtration and decantation
• Evaporation
• Centrifugation
• Simple and fractional distillation
• Magnetic separation
• Flotation
• Sublimation
• Chromatography
Filtration and decantation
Evaporation
Centrifugation
Simple and fractional distillation
Laboratory Distillation Setup
Stone chips are added into the
liquid to allow even and uniform boiling
Cold and hot water enters from the bottom and top of
the condenser respectively. Water will gain heat as vapour condenses. Warmer water is less effective in condensing
vapour
Thermometer at the entrance of the
condenser indicates the boiling point of the type of vapour
entering it
Magnetic separation
Flotation
Sublimation
Chromatography
Mixture Components
Separation
Stationary Phase
Mobile Phase
(1) Mixtures added at the
base line
(2) Paper dipped into solvent for mixtures
(3) Component will run along
paper as it dissolves in
solvent
Components of Essential Oils are separated
Separation of Mixtures
• What are the components in mixture X?
RedX Yellow BlueX Contains Red and Yellow Components
Separation of Mixtures
• How do you separate a mixture of salt, sand and iron?
Salt
Salt
Salt
Iron
IronIronN S
Sand
Sand
Sand
•Magnetic attraction to get iron filings
•Add water to dissolve salt
•Filter to get sand residue
•Evaporate filtrate to get salt