I am Umair Yusuf Mohammad. Class 8TH section: 'A'. This is my Social Assignment. Please check the attachment

1. SCIENCE CHEMISTRY
ASSIGNMENT
ALLOYS AND METALS
FROM,
UMAIR YUSUF
MOHAMMAD
CLASS:8TH
SECTION:A

2. ALLOY
AN ALLOY IS A COMBINATION OF METALS OR METALS COMBINED WITH ONE
OR MORE OTHER ELEMENTS. FOR EXAMPLE, COMBINING THE METALLIC
ELEMENTS GOLD AND COPPER PRODUCES RED GOLD, GOLD
AND SILVER BECOMES WHITE GOLD, AND SILVER COMBINED WITH COPPER
PRODUCES STERLING SILVER. ELEMENTAL IRON, COMBINED WITH NON-
METALLIC CARBON OR SILICON, PRODUCES ALLOYS CALLED STEEL OR SILICON
STEEL. THE RESULTING MIXTURE FORMS A SUBSTANCE WITH PROPERTIES THAT
OFTEN DIFFER FROM THOSE OF THE PURE METALS, SUCH AS INCREASED
STRENGTH OR HARDNESS. UNLIKE OTHER SUBSTANCES THAT MAY CONTAIN
METALLIC BASES BUT DO NOT BEHAVE AS METALS, SUCH AS ALUMINIUM
OXIDE (SAPPHIRE), BERYLLIUM ALUMINIUM SILICATE (EMERALD) OR SODIUM
CHLORIDE (SALT), AN ALLOY WILL RETAIN ALL THE PROPERTIES OF A ALLOYS
ARE USED IN A VERY WIDE APPLICATION FROM STEEL ALLOYS USED IN
EVERYTHING FROM BUILDINGS TO AUTOMOBILES AND MANY WAYS. THE
EXAMPLE OF ALLOYS ARE SOLDER, PEWTER, BRONZE, GERMAN, CARBON, AND
STAINLESS STEEL

3. SOLDER
• solder is an American alloy which is fusible and is:Used to create a permanent bond between
metal workpieces. Solder is melted in order to adhere to and connect the pieces after cooling, which requires that
an alloy suitable for use as solder have a lower melting point than the pieces being joined. The solder should also
be resistant to oxidative and corrosive effects that would degrade the joint over time. Solder used in making
electrical connections also needs to have favourable electrical characteristics. SOFT SOLDER TYPICALLY HAS A MELTING
POINT RANGE OF 90 TO 450 °C (190 TO 840 °F; 360 TO 720 K), AND IS COMMONLY USED IN ELECTRIC, PLUMBING, AND SHEET
METAL WORK. ALLOYS THAT MELT BETWEEN 180 AND 190 °C (360 AND 370 °F; 450 AND 460 K) ARE THE MOST COMMONLY
USED. SOLDERING PERFORMED USING ALLOYS WITH A MELTING POINT ABOVE 450 °C (840 °F; 720 K) IS CALLED "HARD
SOLDERING", "SILVER SOLDERING", OR BRAZING. IN SPECIFIC PROPORTIONS, SOME ALLOYS ARE EUTECTIC — THAT IS, THE
ALLOY'S MELTING POINT IS THE LOWEST POSSIBLE FOR A MIXTURE OF THOSE COMPONENTS, AND COINCIDES WITH THE
FREEZING POINT. NON-EUTECTIC ALLOYS CAN HAVE MARKEDLY DIFFERENT SOLIDUS AND LIQUIDUS TEMPERATURES, AS THEY
HAVE DISTINCT LIQUID AND SOLID TRANSITIONS. NON-EUTECTIC MIXTURES OFTEN EXIST AS A PASTE OF SOLID PARTICLES IN A
MELTED MATRIX OF THE LOWER-MELTING PHASE AS THEY APPROACH HIGH ENOUGH TEMPERATURES. IN ELECTRICAL WORK,
IF THE JOINT IS DISTURBED WHILE IN THIS "PASTY" STATE BEFORE IT FULLY SOLIDIFIES, A POOR ELECTRICAL CONNECTION MAY
RESULT; USE OF EUTECTIC SOLDER REDUCES THIS PROBLEM. THE PASTY STATE OF A NON-EUTECTIC SOLDER CAN BE EXPLOITED
IN PLUMBING, AS IT ALLOWS MELDING OF THE SOLDER DURING COOLING, E.G. FOR ENSURING WATERTIGHT JOINT OF PIPES,
RESULTING IN A SO-CALLED "WIPED JOINT

4. PEWTER
PEWTER IS A METAL ALLOY COMPOSED 85%OF TIN MIXED WITH
10%OF ANTIMONY (KNOWN AS LEAD) 2% COPPER, BISMUTH and
sometimes silver. Copper and antimony act as hardeners but may
be replaced with lead in lower grades of pewter, imparting a bluish
tint. Pewter has a low melting point, around 170–230 °C (338–446
°F), depending on the exact mixture of metals. The word pewter is
probably a variation of the word spelter, a term for zinc alloys
(originally a colloquial name for zinc). In antiquity pewter was tin
alloyed with lead and sometimes copper. Older pewters with
higher lead content are heavier, tarnish faster, and oxidation gives
them a darker silver-gray color. Pewters containing lead are no
longer used in items that will come in contact with the human
body (such as cups, plates, or jewelry) due to health concerns
stemming from the lead content. Modern pewters are available
that are completely free of lead, although many pewters
containing lead are still being produced for other

5. BRONZE
Bronze is an alloy consisting primarily of copper, commonly with
about 12–12.5% tin and often with the addition of other metals
(such as aluminum, manganese, nickel or zinc) and sometimes
non-metals or metalloids such as arsenic, phosphorus or silicon.
These additions produce a range of alloys that may be harder
than copper alone, or have other useful properties, such as
stiffness, ductility, or machinability. The archeological period in
which bronze was the hardest metal in widespread use is known
as the Bronze Age. The beginning of the Bronze Age in India and
western Eurasia is conventionally dated to the mid-4th
millennium BC, and to the early 2nd millennium BC in China;[1]
elsewhere it gradually spread across regions. The Bronze Age
was followed by the Iron Age starting from about 1300 BC and
reaching most of Eurasia by about 500 BC, although bronze
continued to be much more widely used than it is in modern
times.

6. GERMAN SILVERNickel silver, Maillechort, German silver, Argentan, new silver, nickel brass,
albata, alpaca, is a copper alloy with nickel and often zinc. The usual
formulation is 60% copper, 20% nickel and 20% zinc. Nickel silver is named
due to its silvery appearance, but it contains no elemental silver unless
plated. The name "German silver" refers to its development by 19th-
century German metalworkers from the Chinese alloy known as paktong or
baitong ("white copper" or cupronickel).[All modern, commercially
important nickel silvers (such as those standardized under ASTM B122)
contain significant amounts of zinc, and are sometimes considered a
subset of brass.. Nickel silver was first known and used in China.During
the Qing dynasty, it was "smuggled into various parts of the East Indies",
despite a government ban on the export of nickel silver.It became known
in the West from imported wares called baitong (Mandarin) or paktong
(Cantonese) , literally "white copper"), for which the silvery metal colour
was used to imitate sterling silver. According to Berthold Laufer, it was
identical to khar sini, one of the seven metals recognized by Jābir ibn
Hayyān.n Europe, consequently, it was at first called paktong, which is
about the way baitong is pronounced in the Cantonese dialect.[12] The
earliest European mention of paktong occurs in the year 1597. From then

7. CARBON
The term carbon: is from a Latin word carbo which means coal. It is a
chemical element known for its properties it is highly reactive. Its
symbol is C and its atomic number is 6. It is non revelant and non-
metallic. It belongs to group 14 in the periodic table. Carbon is the 15th
most abundant element in the Earth's crust, and the fourth most
abundant element in the universe by mass after hydrogen, helium, and
oxygen. Carbon's abundance, its unique diversity of organic compounds,
and its unusual ability to form polymers at the temperatures commonly
encountered on Earth enables this element to serve as a common
element of all known life. It is the second most abundant element in the
human body by mass (about 18.5%) after oxygen. The atoms of carbon
can bond together in diverse ways, resulting in various allotropes of
carbon. The best known allotropes are graphite, diamond, and
buckminsterfullerene. The physical properties of carbon vary widely
with the allotropic. For example, graphite is opaque and black while
diamond is highly transparent. Graphite is soft enough to form a streak
on paper (hence its name, from the Greek verb "γράφειν" which means
"to write"), while diamond is the hardest naturally occurring material
known. Graphite is a good electrical conductor while diamond has a low
electrical conductivity

8. STAINLESS
STEEL
Stainless steel is a steel which does not rust or gets bad . The stainless
steel can be maintained just by painting it with zinc stainless steel is
used in many steels such as nail cutter so that it does not rust when we
use it or when we wash it. Stainless steel is a very necessary steel it is
helpful in us in many ways. It doesn't comes under the periodic table and
it is not also a chemical. The first found of stainless steel was done in a
event led to the first production of chromium-containing steel by J. Baur
of the Chrome Steel Works of Brooklyn for the construction of bridges. A
U.S. Patent for the product was issued in 1869. This was followed with
recognition of the corrosion resistance of chromium alloys by
Englishmen John T. Woods and John Clark, who noted ranges of
chromium from 5–30%, with added tungsten and "medium carbon". They
pursued the commercial value of the innovation via a British patent for
"Weather-Resistant Alloys