Chemist Work

download Chemist Work

of 54

Transcript of Chemist Work

  • 7/30/2019 Chemist Work

    1/54

    SEKOLAH MENENGAH SAINS BANTING

    JALAN SULEIMAN SHAH JUGRA

    ASSIGNMENT FOR MID YEAR BREAK

    CHEMISTRY FORM 4

    TITLE: Manufactured Subtances In worlds Industries

    NAME: Amirul Syafiq Bin Hasrin

    CLASS: 4 Al-Hasseb

    SUBJECT: Chemistry

    TEACHERS NAME: Puan Hazwani

  • 7/30/2019 Chemist Work

    2/54

    INDEX

    NO CONTENT PAGE

    1.0 Manufacterd of Sulphuric Acid

    1.1 Manufactered of Sulphuric Acid Through contactprocess

    1.2 Uses of sulphuric acid

    1.3 Effect of Acid Rain into the Environment

    1.4 Ways to Control And Reduce Forming of Acid Rain2.0 Manufactered of Ammonia

    2.1 Manufactered of Ammonia through Haber Process

    2.2 Uses of Ammonia

    2.3 Physical and Chemical Properties of Ammonia3.0 Alloy

    3.1 Defination of Alloy

    3.2 Purpose of Making Alloy

    3.3 Composition of Alloy

    3.4 Properties of Alloy

    3.5 Uses of Alloy4.0 Polymers

    4.1 Defination of Polymers

    4.2 Natural Polymers

    4.3 Synthetic Polymers

    4.4 Synthetic Polymers in Daily Life

  • 7/30/2019 Chemist Work

    3/54

  • 7/30/2019 Chemist Work

    4/54

    1.0 MANUFACTERED OF SULPHURIC ACID.

    1.1 Manufactered of Sulphuric Acid Through contact process

    sulphuric acid is a manufactured through the contact process. this process consists of

    three stages. the stages are

    The three stages in the manufacture of Sulphuric acid are as follows :

    1) Creating sulphur dioxide.

    Sulphuric acid was first prepared in the laboratory by a Muslim scientist Jabir-Bin-Hayan. It is one of the most important chemical compounds known. In Pakistan andother countries sulphuric acid is manufactured by the contact process. sulphur dioxideis the chemical compound with the formula SO2. It is a poisonous gas with a pungent,

    irritating smell, that is released by volcanoes and in various industrial processes. In thelab we make sulphur dioxide gas by adding sulphuric acid to some sodium metabisulfitepowder and warming it.

    This can either be made by burning sulphur in an excess of air:

    . . . or by heating sulphide ores like pyrite in an excess of air:

    http://en.wikipedia.org/wiki/Chemical_compoundhttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Volcanohttp://en.wikipedia.org/wiki/Volcanohttp://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Sulfurhttp://en.wikipedia.org/wiki/Chemical_compound
  • 7/30/2019 Chemist Work

    5/54

    2) Transforming sulphur dioxide into sulphur trioxide.

    This is a reversible reaction, and the formation of the sulphur trioxide is exothermic.

    A flow scheme for this part of the process looks like this:

    Diagram 1.1 a flow scheme of sulphur trioxide

    The reasons for all these conditions will be explored in detail further down the page.

    Converting the sulphur trioxide into sulphuric acid

    This can't be done by simply adding water to the sulphur trioxide - the reaction is so

    uncontrollable that it creates a fog of sulphuric acid. Instead, the sulphur trioxide is first

    dissolved in concentrated sulphuric acid:

    The product is known as fuming sulphuric acid or oleum.

  • 7/30/2019 Chemist Work

    6/54

    This can then be reacted safely with water to produce concentrated sulphuric acid -

    twice as much as you originally used to make the fuming sulphuric acid.

    The temperature

    Equilibrium considerations

    You need to shift the position of the equilibrium as far as possible to the right in order to

    produce the maximum possible amount of sulphur trioxide in the equilibrium mixture.

    The forward reaction (the production of sulphur trioxide) is exothermic.

    According to Le Chatelier's Principle, this will be favoured if you lower the temperature.

    The system will respond by moving the position of equilibrium to counteract this - in

    other words by producing more heat.

    In order to get as much sulphur trioxide as possible in the equilibrium mixture, you need

    as low a temperature as possible. However, 400 - 450C isn't a low temperature

    The pressure

    Equilibrium considerations

    Notice that there are 3 molecules on the left-hand side of the equation, but only 2 on the

    right.

    According to Le Chatelier's Principle, if you increase the pressure the system will

    respond by favouring the reaction which produces fewer molecules. That will cause the

    pressure to fall again.

    In order to get as much sulphur trioxide as possible in the equilibrium mixture, you need

    as high a pressure as possible. High pressures also increase the rate of the reaction.However, the reaction is done at pressures close to atmospheric pressure!

    Economic considerations

    Even at these relatively low pressures, there is a 99.5% conversion of sulphur dioxide

    into sulphur trioxide. The very small improvement that you could achieve by increasing

    the pressure isn't worth the expense of producing those high pressures.

  • 7/30/2019 Chemist Work

    7/54

    The catalyst

    Equilibrium considerations

    The catalyst has no effect whatsoever on the position of the equilibrium. Adding a

    catalyst doesn't produce any greater percentage of sulphur trioxide in the equilibrium

    mixture. Its only function is to speed up the reaction.

    Rate considerations

    In the absence of a catalyst the reaction is so slow that virtually no reaction happens in

    any sensible time. The catalyst ensures that the reaction is fast enough for a dynamic

    equilibrium to be set up within the very short time that the gases are actually in the

    reactor.

  • 7/30/2019 Chemist Work

    8/54

    3) Transforming sulphur trioxide into sulphuric acid

    This can't be done by simply adding water to the sulphur trioxide - the reaction is so

    uncontrollable that it creates a fog of sulphuric acid. Instead, the sulphur trioxide is firstdissolved in concentrated sulphuric acid:

    H2SO4(l) + SO3(g) H2S2O7(l)

    The product is known as fuming sulphuric acid or oleum.

    This can then be reacted safely with water to produce concentrated sulphuric acid -

    twice as much as you originally used to make the fuming sulphuric acid.

    H2S2O7(l) + H2O(l) 2 H2SO4(l)

    The average percentage yield of this reaction is around 30%.

    The chemical formula for oleum is:

    H2S2O7

    1.2 Usesof sulphuric acid

    A s an important industrial chemical

    I n the manufacture of fertilisers (e.g., ammonium sulphate, superphosphate)

    I n petroleum refining

    I n detergent industry

    I n the manufacture of pigments, paints, and dyestuff intermediates

  • 7/30/2019 Chemist Work

    9/54

    1.3 Effect of Acid Rain into the Environment.

    Effects of acid rain on surface waters and aquatic animals

    The ecological effects of acid rain are most clearly seen in the aquatic, or water,

    environments, such as streams, lakes, and marshes. Acid rain flows into streams, lakes,and marshes after falling on forests, fields, buildings, and roads. Acid rain also falls

    directly on aquatic habitats. Most lakes and streams have a pH between 6 and 8,

    although some lakes are naturally acidic even without the effects of acid rain. Acid rain

    primarily affects sensitive bodies of water, which are located in watersheds whose soils

    have a limited ability to neutralize acidic compounds (called buffering capacity). Lakes

    and streams become acidic (i.e., the pH value goes down) when the water itself and its

    surrounding soil cannot buffer the acid rain enough to neutralize it. In areas where

    buffering capacity is low, acid rain releases aluminum from soils into lakes and streams;

    aluminum is highly toxic to many species of aquatic organisms.

    Effects of acid rain on fish and other aquatic organism

    Acid rain causes a cascade of effects that harm or kill individual fish, reduce fish

    population numbers, completely eliminate fish species from a waterbody, and decrease

    biodiversity. As acid rain flows through soils in a watershed, aluminum is released from

    soils into the lakes and streams located in that watershed. So, as pH in a lake or stream

    decreases, aluminum levels increase. Both low pH and increased aluminum levels are

    directly toxic to fish. In addition, low pH and increased aluminum levels cause chronic

    stress that may not kill individual fish, but leads to lower body weight and smaller size

    and makes fish less able to compete for food and habitat.

    Some types of plants and animals are able to tolerate acidic waters. Others, however,

    are acid-sensitive and will be lost as the pH declines. Generally, the young of most

    species are more sensitive to environmental conditions than adults. At pH 5, most fish

    eggs cannot hatch. At lower pH levels, some adult fish die. Some acid lakes have no

    fish. The chart below shows that not all fish, shellfish, or the insects that they eat can

    tolerate the same amount of acid; for example, frogs can tolerate water that is more

    acidic (i.e., has a lower pH) than trout.

    Effects of acid rain on ecosystem

    Together, biological organisms and the environment in which they live are called an

    ecosystem. The plants and animals living within an ecosystem are highly

    interdependent. For example, frogs may tolerate relatively high levels of acidity, but if

  • 7/30/2019 Chemist Work

    10/54

    they eat insects like the mayfly, they may be affected because part of their food supply

    may disappear. Because of the connections between the many fish, plants, and other

    organisms living in an aquatic ecosystem, changes in pH or aluminum levels affect

    biodiversity as well. Thus, as lakes and streams become more acidic, the numbers and

    types of fish and other aquatic plants and animals that live in these waters decrease.

    Effects of acid rain on plant life.

    Both natural vegetation and crops are affected by acid rain. The roots are damaged by

    acidic rainfall, causing the growth of the plant to be stunted, or even in its death.

    Nutrients present in the soil, are destroyed by the acidity. Useful micro organisms which

    release nutrients from decaying organic matter, into the soil are killed off, resulting in

    less nutrients being available for the plants. The acid rain, falling on the plants damages

    the waxy layer on the leaves and makes the plant vulnerable to diseases. Thecumulative effect means that even if the plant survives it will be very weak and unable to

    survive climatic conditions like strong winds, heavy rainfall, or a short dry period. Plant

    germination and reproduction is also inhibited by the effects of acid rain.

    Effects on animals and birds.

    All living organisms are interdependent on each other. If a lower life form is killed, other

    species that depended on it will also be affected. Every animal up the food chain will be

    affected. Animals and birds, like waterfowl orbeavers, which depended on the water for

    food sources or as a habitat, also begin to die. Due to the effects of acid rain, animals

    which depended on plants for their food also begin to suffer. Tree dwelling birdsand

    animals also begin to languish due to loss of habitat.

    Effects on human beings

    Mankind depends upon plants and animals for food. Due to acid rain the entire fish

    stocks in certain lakes have been wiped out. The economic livelihood of people who

    depended on fish and other aquatic life suffers as a result. Eating fish which may have

    been contaminated by mercury can cause serious health problems. In addition to loss of

    plant and animal life as food sources, acid rain gets into the food we eat, the water we

    drink, as well as the air we breathe. Due to this asthmatic people and children aredirectly affected. Urban drinking water supplies are generally treated to neutralise some

    of the effects of acid rain and therefore city dwellers may not directly suffer due to

    acidified drinking water. But out in the rural areas, those depending upon lakes, rivers,

    and wells will feel the effects of acid rain on their health. The acidic water moving

    through pipes causes harmful elements like lead and copper to be leached into the

    water. Aluminium which dissolves more easily in acid rain as compared to pure rainfall,

    http://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htm
  • 7/30/2019 Chemist Work

    11/54

    has been linked to Alzheimers disease. The treatment of urban water supplies may not

    include removal of elements like Aluminium, and so is a serious problem in cities too.

    Other effects

    All living things, whether plants or animals, whether living on land or in the water ortrees, are affected either directly or indirectly by acid rain. Even buildings, bridges and

    other structures are affected. In cities, paint from buildings have peeled off and colours

    of cars have faded due to the effects of acid rain. From the Taj Mahal in India to the

    Washington Monument great buildings all over the world have been affected by the acid

    rainfall which causescorrosion, fracturing, and discoloration in the structures. In

    Europe, structures like The Acropolis in Greece and Renaissance buildings in Italy, as

    well as several churches and cathedrals have suffered visible damage. In the Yucatan

    peninsula in Mexico, and in places in South America, ancient Mayan Pyramids are

    being destroyed by the acid rain. Temples, murals, and ancient inscriptions which had

    previously survived for centuries are now showing severe signs of corrosion. Evenbooks, manuscripts, paintings, and sculpture are being affected inmuseumsand

    libraries, where the ventilation system cannot eliminate the acid particles from the air

    which circulates in the building. In some parts of Poland, trains are required to run

    slowly, as the tracks are badly damaged due to corrosion caused by acid rainfall.

    http://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htmhttp://www.essortment.com/all/acidraineffect_rqmz.htm
  • 7/30/2019 Chemist Work

    12/54

    1.4 Ways to Control And Reduce Forming of Acid Rain

    Government agencies and scientists are not the only ones that can take action to stop

    acid rain. You can become part of the solution, too!

    Understand the Problem

    The first step you can take to help control acid rain is to understand the problem and its

    solutions. Now that you have learned about this environmental issue, you can tell others

    about it. By telling your classmates, parents, and teachers about what you learned on

    this site, you can help educate them about the problem of acid rain. You CAN make a

    difference!

    Conserve Energy

    Since energy production creates large amounts of the pollutants that cause acid rain,

    one important step you can take is to conserve energy. You can do this in a number of

    ways:

    Turn off lights, computers, televisions, video games, and other electrical

    equipment when you're not using them.

    Encourage your parents to buy equipment that uses less electricity, including

    lights, air conditioners, heaters, refrigerators, and washing machines. Such

    equipment might have theEnergy Starlabel.

    Try to limit the use of air conditioning.

    Ask your parents to adjust the thermostat (the device used to control the

    temperature in your home) when you go on vacation.

    Minimize the Miles

    Driving cars and trucks also produces large amounts of nitrogen oxides, which cause

    acid rain. To help cut down on air pollution from cars, you can carpool or take public

    transportation, such as buses and trains. Also, ask your parents to walk or bike with you

    to a nearby store or friends house instead of driving.

    http://www.epa.gov/acidrain/education/site_students/glossary.html#eshttp://www.epa.gov/acidrain/education/site_students/glossary.html#eshttp://www.epa.gov/acidrain/education/site_students/glossary.html#eshttp://www.epa.gov/acidrain/education/site_students/glossary.html#es
  • 7/30/2019 Chemist Work

    13/54

    2.0 MANUFACTERED OF AMMONIA

    2.1 Manufactered of Ammonia through Haber Process

    History

    Early in the twentieth century, several chemists tried to make ammonia from

    atmospheric nitrogen. German chemist Fritz Haberdiscovered a process that is still

    used today. Robert Le Rossignol was instrumental in the development of the high-

    pressure devices used in the Haber process. They demonstrated their process in the

    summer of 1909 by producing ammonia from air drop by drop, at the rate of about

    125 ml (4 US fl oz) per hour. The process was purchased by the German chemical

    company BASF, which assigned Carl Bosch the task of scaling up Haber's tabletop

    machine to industrial-level production.[2][7]

    Haber and Bosch were later awarded Nobel

    prizes, in 1918 and 1931 respectively, for their work in overcoming the chemical and

    engineering problems posed by the use of large-scale, continuous-flow, high-pressure

    technology. Ammonia was first manufactured using the Haber process on an industrial

    scale in 1913 in BASF's Oppau plant in Germany. During World War I, production was

    shifted from fertilizer to explosives, particularly through the conversion of ammonia into

    a synthetic form ofChile saltpeter, which could then be changed into other substances

    for the production of gunpowder and high explosives. The Allies had access to large

    amounts of saltpeter from natural nitrate deposits in Chile that belonged almost totally to

    British industries; Germany had to produce its own. It has been suggested that without

    this process, Germany would not have fought the war,[8]

    or would have had to surrenderyears earlier.

    Figure 1.1 Fritz Harber

    http://en.wikipedia.org/wiki/Fritz_Haberhttp://en.wikipedia.org/wiki/Robert_Le_Rossignolhttp://en.wikipedia.org/wiki/BASFhttp://en.wikipedia.org/wiki/Carl_Boschhttp://en.wikipedia.org/wiki/Haber_process#cite_note-hager-1http://en.wikipedia.org/wiki/Haber_process#cite_note-hager-1http://en.wikipedia.org/wiki/Haber_process#cite_note-hager-1http://en.wikipedia.org/wiki/Nobel_Prizehttp://en.wikipedia.org/wiki/Nobel_Prizehttp://en.wikipedia.org/wiki/Sodium_nitratehttp://en.wikipedia.org/wiki/Nitratehttp://en.wikipedia.org/wiki/Haber_process#cite_note-ny_times-7http://en.wikipedia.org/wiki/Haber_process#cite_note-ny_times-7http://en.wikipedia.org/wiki/Haber_process#cite_note-ny_times-7http://en.wikipedia.org/wiki/Haber_process#cite_note-ny_times-7http://en.wikipedia.org/wiki/Nitratehttp://en.wikipedia.org/wiki/Sodium_nitratehttp://en.wikipedia.org/wiki/Nobel_Prizehttp://en.wikipedia.org/wiki/Nobel_Prizehttp://en.wikipedia.org/wiki/Haber_process#cite_note-hager-1http://en.wikipedia.org/wiki/Haber_process#cite_note-hager-1http://en.wikipedia.org/wiki/Carl_Boschhttp://en.wikipedia.org/wiki/BASFhttp://en.wikipedia.org/wiki/Robert_Le_Rossignolhttp://en.wikipedia.org/wiki/Fritz_Haber
  • 7/30/2019 Chemist Work

    14/54

    The Process

    Synthesis gas preparation

    The methane is first cleaned, mainly to remove sulfur oxide and hydrogensulfide impurities that would poison the catalysts.

    The clean methane is then reacted with steam over a catalyst ofnickel oxide. This is

    called steam reforming:

    CH4 + H2O CO + 3 H2

    Secondary reforming then takes place with the addition of air to convert the methane

    that did not react during steam reforming:

    2 CH4 + O2 2 CO + 4 H2

    CH4 + 2 O2 CO2 + 2 H2O

    Then the water gas shift reaction yields more hydrogen from CO and steam:

    CO + H2O CO2 + H2

    The gas mixture is now passed into a methanator[9] which converts most of the

    remaining CO into methane for recycling:

    CO + 3 H2 CH4 + H2O

    This last step is necessary as carbon monoxide poisons the catalyst. (Note, this

    reaction is the reverse of steam reforming). The overall reaction so far turns methane

    and steam into carbon dioxide, steam, and hydrogen.

    [edit]Ammonia synthesis Haber process

    The final stage, which is the actual Haber process, is the synthesis of ammonia using

    an iron catalyst promoted with K2O, CaO and Al2O3:[citation needed]

    N2 (g) + 3 H2 (g) 2 NH3 (g) (H = 92.22 kJmol1)

    This is done at 1525 MPa (150250 bar) and between 300 and 550 C, as the gases

    are passed over four beds of catalyst, with cooling between each pass so as to maintain

    a reasonable equilibrium constant. On each pass only about 15% conversion occurs,

    but any unreacted gases are recycled, and eventually an overall conversion of 97% is

    achieved.[citation needed]

    http://en.wikipedia.org/wiki/Sulfur_oxidehttp://en.wikipedia.org/wiki/Hydrogen_sulfidehttp://en.wikipedia.org/wiki/Hydrogen_sulfidehttp://en.wikipedia.org/wiki/Steamhttp://en.wikipedia.org/wiki/Nickel_oxidehttp://en.wikipedia.org/wiki/Steam_reforminghttp://en.wikipedia.org/wiki/Water_gas_shift_reactionhttp://en.wikipedia.org/wiki/Haber_process#cite_note-8http://en.wikipedia.org/w/index.php?title=Haber_process&action=edit&section=4http://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Mole_(unit)http://en.wikipedia.org/wiki/Pascal_(unit)http://en.wikipedia.org/wiki/Bar_(unit)http://en.wikipedia.org/wiki/Equilibrium_constanthttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Equilibrium_constanthttp://en.wikipedia.org/wiki/Bar_(unit)http://en.wikipedia.org/wiki/Pascal_(unit)http://en.wikipedia.org/wiki/Mole_(unit)http://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/w/index.php?title=Haber_process&action=edit&section=4http://en.wikipedia.org/wiki/Haber_process#cite_note-8http://en.wikipedia.org/wiki/Water_gas_shift_reactionhttp://en.wikipedia.org/wiki/Steam_reforminghttp://en.wikipedia.org/wiki/Nickel_oxidehttp://en.wikipedia.org/wiki/Steamhttp://en.wikipedia.org/wiki/Hydrogen_sulfidehttp://en.wikipedia.org/wiki/Hydrogen_sulfidehttp://en.wikipedia.org/wiki/Sulfur_oxide
  • 7/30/2019 Chemist Work

    15/54

  • 7/30/2019 Chemist Work

    16/54

    Temperature

    1) Temperature between 450 C and 500 C.

    The forward reaction (to form ammonia) is exothermic (it gives out heat). The backwardreaction is endothermic (it takes in heat).

    nitrogen + hydrogen ammonia ( + heat).

    N2(g) + 3H2(g) 2NH3(g) ( + heat).

    If we treat heat as a product, then removing heat (cooling the reaction down) will result

    in the equilibrium mixture having more ammonia (see Le Chatelier's Principle).

    Since we want ammonia from the Haber Process, why is the reaction conducted

    at 450 C ? Why don't we cool it with ice, or at least let it run at room temperature?

    If we look at the section on reaction rates, and the page that deals with

    the effect oftemperature, we can see that all reactions go faster when

    the temperature is raised.

    In a reversible reaction like the Haber Process, raising the temperature will make

    the equilibrium mixture have more nitrogen and hydrogen because forming

    these from ammonia takes heat in.

    If we cool the reaction down, the amount of ammonia in the equilibrium

    mixture will increase, but the rate at which ammonia is formed will decrease(because the temperature is lower).

    It is no good having 90% ammonia in the equilibrium mixture if it takes all day to

    make one bucket full. It is better to have 10% ammonia being made very quickly, and at

    the end of the day you can have thousands of litres.

    The actual temperature of between 450 C and 500 C, is a compromise between

    the amount of ammonia in the equilibrium mixture (only 15% because of the high

    temperature) and the rate at which ammonia is formed (fast because of the high

    temperature).

    http://www.gcsescience.com/rc22-exothermic-endothermic.htmhttp://www.gcsescience.com/rc22-exothermic-endothermic.htmhttp://www.gcsescience.com/h4.htmhttp://www.gcsescience.com/h5.htmhttp://www.gcsescience.com/rc6-increase-temperature.htmhttp://www.gcsescience.com/rc6-increase-temperature.htmhttp://www.gcsescience.com/rc6-increase-temperature.htmhttp://www.gcsescience.com/rc6-increase-temperature.htmhttp://www.gcsescience.com/h5.htmhttp://www.gcsescience.com/h4.htmhttp://www.gcsescience.com/rc22-exothermic-endothermic.htmhttp://www.gcsescience.com/rc22-exothermic-endothermic.htm
  • 7/30/2019 Chemist Work

    17/54

    Pressure

    The industrial conditions are 2) Pressure of 200 atm (200 atmospheres).

    Why is such a high pressure used?

    nitrogen + hydrogen ammonia ( + heat).

    N2(g) + 3H2(g) 2NH3(g) ( + heat).

    If we look at the reaction, the reactants and products are gases. One mole of any

    gas occupies a volume of 24,000 cm3.

    On the left side of the equation, there is one mole of nitrogen, and three

    moles of hydrogen. The total is four moles of reactant. (If you don't know why there

    are 3 moles of hydrogen and 1 mole of nitrogen, see moles).

    On the right side of the equation (the product), there are two moles of ammonia.

    So, four moles of reactant give two moles of product. Since one mole of any gas takes

    up the same volume, the volume of product is only half the volume of reactants.

    Increasing the pressure (from Le Chatelier's Principle) makes the equilibrium

    mixture have more ammonia. This is what we want! What effect does pressure have

    on reaction rate? As we can see, increased pressure also increases the reaction rate.

    Again, this is what we want!

    Q. Why not increase the pressure to 1,000 atm, and get lots of ammonia really quickly?

    A. In the real world, it all comes down to money. Building high pressure chemical

    plant is expensive. Running the reaction at about 200 atm gives the highest

    return (the biggest profit) on investment capital (the amount of money you spend to set

    up the whole thing).

    http://www.gcsescience.com/h2.htmhttp://www.gcsescience.com/m20.htmhttp://www.gcsescience.com/m8.htmhttp://www.gcsescience.com/h5.htmhttp://www.gcsescience.com/rc8-increase-pressure.htmhttp://www.gcsescience.com/rc8-increase-pressure.htmhttp://www.gcsescience.com/rc8-increase-pressure.htmhttp://www.gcsescience.com/rc8-increase-pressure.htmhttp://www.gcsescience.com/h5.htmhttp://www.gcsescience.com/m8.htmhttp://www.gcsescience.com/m20.htmhttp://www.gcsescience.com/h2.htm
  • 7/30/2019 Chemist Work

    18/54

    Diagram 1.2 Haber process.

  • 7/30/2019 Chemist Work

    19/54

    2.2 Uses of Ammonia

    Most of the ammonia used in the world is used in fertilizer either in salt or liquid

    form.

    Almost all synthetically derived nitrogen is made from ammonia. Nitric acid is

    used in fertilizers and explosives.

    Household ammonia is used as a surface cleaner in a diluted form. It most

    commonly used to clean glass, porcelain and stainless steel as it leaves no

    streaks.

    Ammonia is the main ingredient in most oven cleaners.

    Ammonia is used in industrial refrigeration applications and hockey rinks as it has

    favorable vaporization properties.

    It is used in geothermal power plants in an ammonia-water mixture that is boiled.

    Ammonia is used to scrub Sulfur dioxide from the burning fossil fuels used in

    power plants. It is also used to neutralize the nitrogen oxide produced by diesel

    engines.

    It is used in animal feed as an antimicrobial. It is also used to disinfect beef

    products before sale.

    Liquid ammonia is used in textiles to treat cotton materials and in the pre-

    washing of wool.

  • 7/30/2019 Chemist Work

    20/54

    2.3 Physical and Chemichal Properties of Ammonia

    Physical Properties

    Anhydrous ammonia is a clear liquid that boils at a temperature of -28F. In refrigeration

    systems, the liquid is stored in closed containers under pressure. When the pressure isreleased, the liquid evaporates rapidly, generally forming an invisible vapor or gas. The

    rapid evaporation causes the temperature of the liquid to drop until it reaches the

    normal boiling point of -28F, a similar effect occurs when water evaporates off the skin,

    thus cooling it. This is why ammonia is used in refrigeration systems.

    Liquid anhydrous ammonia weighs less than water. About eight gallons of ammonia

    weighs the same as five gallons of water.

    Liquid and gas ammonia expand and contract with changes in pressure and

    temperature. For example, if liquid anhydrous ammonia is in a partially filled, closedcontainer it is heated from 0F to 68F, the volume of the liquid will increase by about 10

    percent. If the tank is 90 percent full at 0F, it will become 99 percent full at 68F. At the

    same time, the pressure in the container will increase from 16 pounds per square inch

    (psi) to 110 psi.

    Liquid ammonia will expand by 850 times when evaporating:

    Anhydrous ammonia gas is considerably lighter than air and will rise in dry air. However,

    because of ammonias tremendous affinity for water, it reacts immediately with the

    humidity in the air and may remain close to the ground.

    The odor threshold for ammonia is between 5 - 50 parts per million (ppm) of air. The

    permissible exposure limit (PEL) is 50 ppm averaged over an 8 hour shift. It is

    recommended that if an employee can smell it they ought to back off and determine if

    they need to be using respiratory protection.

  • 7/30/2019 Chemist Work

    21/54

    Chemical Properties

    Anhydrous ammonia is easily absorbed by water. At 68F, about 700 volumes of vapor

    can be dissolved in one volume of water to make a solution containing 34 percent

    ammonia by weight. Ammonia in water solution is called aqua ammonia or ammonium

    hydroxide.

    Ammonia, especially in the presence of moisture, reacts with and corrodes copper, zinc,

    and many alloys. Only iron, steel, certain rubbers and plastics, and specific nonferrous

    alloys resistant to ammonia should be used for fabrications of anhydrous ammonia

    containers, fittings, and piping.

    Ammonia will combine with mercury to form a fulminate which is an unstable explosive

    compound.

    Anhydrous ammonia is classified by the Department of Transportation as

    nonflammable. However, ammonia vapor in high concentrations (16 to 25 percent by

    weight in air) will burn. It is unlikely that such concentrations will occur except in

    confined spaces or in the proximity of large spills. The fire hazard from ammonia is

    increased by the presence of oil or other combustible materials.

    Anhydrous ammonia is an alkali.

  • 7/30/2019 Chemist Work

    22/54

    3.0 ALLOY

    3.1 Defination of Alloy

    A material that has metallic properties and is composed of two or more chemical

    elements of which at least one is a metal (i.e. steel is an alloy of carbon in iron;

    stainless steel is an alloy of carbon, chromium and sometimes nickel in iron.)

    3.2 Purpose of Making Alloy

    Pure metals possess few important physical and metallic properties, such as melting

    point, boiling point, density, specific gravity, high malleability, ductility, and heat and

    electrical conductivity. These properties can be modified and enhanced by alloying itwith some other metal or nonmetal, according to the need.

    Alloys are made to:

    Enhance the hardness of a metal: An alloy is harder than its components. Pure

    metals are generally soft. The hardness of a metal can be enhanced by alloying it

    with another metal or nonmetal.

    Lower the melting point: Pure metals have a high melting point. The melting point

    lowers when pure metals are alloyed with other metals or nonmetals. This makes

    the metals easily fusible. This property is utilized to make useful alloys calledsolders.

    Enhance tensile strength: Alloy formation increases the tensile strength of the

    parent metal.

    Enhance corrosion resistance: Alloys are more resistant to corrosion than pure

    metals. Metals in pure form are chemically reactive and can be easily corroded

    by the surrounding atmospheric gases and moisture. Alloying a metal increases

    the inertness of the metal, which, in turn, increases corrosion resistance.

    Modify color: The color of pure metal can be modified by alloying it with other

    metals or nonmetals containing suitable color pigments.

    Provide better castability: One of the most essential requirements of getting good

    castings is the expansion of the metal on solidification. Pure molten metals

    undergo contraction on solidification. Metals need to be alloyed to obtain good

    castings because alloys expand.

  • 7/30/2019 Chemist Work

    23/54

    3.3 Composition of Alloy

    Gold Alloys

    Color of Gold Alloy Composition

    Yellow Gold (22K) Gold 91.67%Silver 5%Copper 2%Zinc 1.33%

    Red Gold (18K) Gold 75%Copper 25%

    Rose Gold (18K) Gold 75%Copper 22.25%Silver 2.75%

    Pink Gold (18K) Gold 75%Copper 20%

    Silver 5%

    White Gold (18K) Gold 75%Platinum or Palladium 25%

    Copper Alloy

    ML

    CuAl8

    ML

    CuAl9Fe

    ML

    CuMn13Al7

    ML

    CuNi10Fe

    ML

    CuNi30Fe

    ML

    CuSi3

    ML

    CuSi28L

    ML

    CuSn

    ML

    CuSn6

    ML

    CuAl8Ni2

    ML

    CuAl8Ni6

    Al6,00-

    8,50

    8,50-

    11,007,00-8,50 0,03 0,02 0,02 0,01 0,01

    7,00 -

    9,50

    8,50 -

    9,50

    Si 0,20 0,10 0,10 0,20 0,202,80-

    4,00

    2,80-

    3,00

    0,10-

    0,400,20 0,10

    Mn 0,50 11,00-14,000,50 -

    1,50

    0,50 -

    1,50

    0,50-

    1,50

    0,75-

    0,95

    0,10-

    0,40

    0,50 -

    2,50

    0,60 -

    3,50

    Ni 1,50-3,009,00 -

    11,00

    29,0 -

    32,00,05 0,10

    0,50 -

    3,00

    4,00 -

    5,50

    Zn 0,20 0,02 0,15 0,40 0,10 0,10 0,20 0,10

    Sn 0,20 0,050,50-

    1,00

    4,00-

    7,00

    Pb 0,02 0,02 0,02 0,02 0,02 0,02 0,01 0,015 0,02 0,02 0,02

    Ti0,20 -

    0,50

    0,20 -

    0,50

    http://www.migweld.de/english/products/copper/ml-cual8.htmlhttp://www.migweld.de/english/products/copper/ml-cual8.htmlhttp://www.migweld.de/english/products/copper/ml-cual8.htmlhttp://www.migweld.de/english/products/copper/ml-cual9fe.htmlhttp://www.migweld.de/english/products/copper/ml-cual9fe.htmlhttp://www.migweld.de/english/products/copper/ml-cual9fe.htmlhttp://www.migweld.de/english/products/copper/ml-cumn13al7.htmlhttp://www.migweld.de/english/products/copper/ml-cumn13al7.htmlhttp://www.migweld.de/english/products/copper/ml-cuni10fe.htmlhttp://www.migweld.de/english/products/copper/ml-cuni10fe.htmlhttp://www.migweld.de/english/products/copper/ml-cuni10fe.htmlhttp://www.migweld.de/english/products/copper/ml-cuni10fe.htmlhttp://www.migweld.de/english/products/copper/ml-cuni30fe.htmlhttp://www.migweld.de/english/products/copper/ml-cuni30fe.htmlhttp://www.migweld.de/english/products/copper/ml-cuni30fe.htmlhttp://www.migweld.de/english/products/copper/ml-cusi3.htmlhttp://www.migweld.de/english/products/copper/ml-cusi3.htmlhttp://www.migweld.de/english/products/copper/ml-cusi3.htmlhttp://www.migweld.de/english/products/copper/ml-cusi28l.htmlhttp://www.migweld.de/english/products/copper/ml-cusi28l.htmlhttp://www.migweld.de/english/products/copper/ml-cusi28l.htmlhttp://www.migweld.de/english/products/copper/ml-cusn.htmlhttp://www.migweld.de/english/products/copper/ml-cusn.htmlhttp://www.migweld.de/english/products/copper/ml-cusn.htmlhttp://www.migweld.de/english/products/copper/ml-cusn6.htmlhttp://www.migweld.de/english/products/copper/ml-cusn6.htmlhttp://www.migweld.de/english/products/copper/ml-cual8ni2.htmlhttp://www.migweld.de/english/products/copper/ml-cual8ni2.htmlhttp://www.migweld.de/english/products/copper/ml-cual8ni2.htmlhttp://www.migweld.de/english/products/copper/ml-cual8ni2.htmlhttp://www.migweld.de/english/products/copper/ml-cual8ni6.htmlhttp://www.migweld.de/english/products/copper/ml-cual8ni6.htmlhttp://www.migweld.de/english/products/copper/ml-cual8ni6.htmlhttp://www.migweld.de/english/products/copper/ml-cual8ni6.htmlhttp://www.migweld.de/english/products/copper/ml-cual8ni6.htmlhttp://www.migweld.de/english/products/copper/ml-cual8ni2.htmlhttp://www.migweld.de/english/products/copper/ml-cual8ni2.htmlhttp://www.migweld.de/english/products/copper/ml-cusn6.htmlhttp://www.migweld.de/english/products/copper/ml-cusn6.htmlhttp://www.migweld.de/english/products/copper/ml-cusn.htmlhttp://www.migweld.de/english/products/copper/ml-cusn.htmlhttp://www.migweld.de/english/products/copper/ml-cusi28l.htmlhttp://www.migweld.de/english/products/copper/ml-cusi28l.htmlhttp://www.migweld.de/english/products/copper/ml-cusi3.htmlhttp://www.migweld.de/english/products/copper/ml-cusi3.htmlhttp://www.migweld.de/english/products/copper/ml-cuni30fe.htmlhttp://www.migweld.de/english/products/copper/ml-cuni30fe.htmlhttp://www.migweld.de/english/products/copper/ml-cuni10fe.htmlhttp://www.migweld.de/english/products/copper/ml-cuni10fe.htmlhttp://www.migweld.de/english/products/copper/ml-cumn13al7.htmlhttp://www.migweld.de/english/products/copper/ml-cumn13al7.htmlhttp://www.migweld.de/english/products/copper/ml-cual9fe.htmlhttp://www.migweld.de/english/products/copper/ml-cual9fe.htmlhttp://www.migweld.de/english/products/copper/ml-cual8.htmlhttp://www.migweld.de/english/products/copper/ml-cual8.html
  • 7/30/2019 Chemist Work

    24/54

    3.4 Properties of Alloy

    Mechanical Properties

    Properties

    Conditions

    T (C) Treatment

    Density (1000 kg/m ) 8 25

    Poisson's Ratio 0.27-0.30 25

    Elastic Modulus (GPa) 193 25

    Tensile Strength (Mpa) 515

    25 hot finished and annealed (wire)more

    Yield Strength (Mpa) 205

    Elongation (%) 40

    Reduction in Area (%) 50

    Hardness (HRB) 95 (max) 25 annealed (plate, sheet, strip)

    Thermal Properties

    Properties

    Conditions

    T (C) Treatment

    Thermal Expansion (10- /C) 15.9 0-100more

    Thermal Conductivity (W/m-K) 16.2 100more

    http://www.efunda.com/units/convert_units.cfm?From=190&mrn=8000#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=190&mrn=8000#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=319&mrn=193#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=339&mrn=515#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=339&mrn=515#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=uts&Page_Title=Alloys%20Propertieshttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=uts&Page_Title=Alloys%20Propertieshttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=uts&Page_Title=Alloys%20Propertieshttp://www.efunda.com/units/convert_units.cfm?From=339&mrn=205#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=339&mrn=205#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=876&mrn=1%2E59#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=876&mrn=1%2E59#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=0#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=0#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=100#ConvIntohttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=cte&Page_Title=Alloys%20Propertieshttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=cte&Page_Title=Alloys%20Propertieshttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=cte&Page_Title=Alloys%20Propertieshttp://www.efunda.com/units/convert_units.cfm?From=245&mrn=16%2E2#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=245&mrn=16%2E2#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=100#ConvIntohttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=tc&Page_Title=Alloys%20Propertieshttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=tc&Page_Title=Alloys%20Propertieshttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=tc&Page_Title=Alloys%20Propertieshttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=tc&Page_Title=Alloys%20Propertieshttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=100#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=245&mrn=16%2E2#ConvIntohttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=cte&Page_Title=Alloys%20Propertieshttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=100#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=0#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=876&mrn=1%2E59#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=339&mrn=205#ConvIntohttp://www.efunda.com/materials/alloys/alloy_home/show_alloy_found.cfm?ID=AISI_Type_316&show_prop=uts&Page_Title=Alloys%20Propertieshttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=339&mrn=515#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=319&mrn=193#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=190&mrn=8000#ConvInto
  • 7/30/2019 Chemist Work

    25/54

    Specific Heat (J/kg-K) 500 0-100

    Electric Properties

    Properties

    Conditions

    T (C) Treatment

    Electric Resistivity (10- W-m) 740 25

    http://www.efunda.com/units/convert_units.cfm?From=886&mrn=500#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=886&mrn=500#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=0#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=100#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=100#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=100#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=392&mrn=7%2E4#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=392&mrn=7%2E4#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=25#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=392&mrn=7%2E4#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=100#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=55&mrn=0#ConvIntohttp://www.efunda.com/units/convert_units.cfm?From=886&mrn=500#ConvInto
  • 7/30/2019 Chemist Work

    26/54

  • 7/30/2019 Chemist Work

    27/54

    3.5 Uses of Alloy

    Stainless Steel Alloy and its Uses

    This name stainless steel is commonly referred to those metal alloys comprising 10.5%

    or more Chromium (Cr) and 50% Iron (Fe) in it. There are different types of stainless

    steel depending on the amount of chromium, iron and other metals in them. Thechromium present in it gives stainless steel its highly corrosion resistant property. Pure

    iron is unstable and corrodes naturally by rust formation. By the addition of chromium,

    iron is prevented from combining with oxygen and water to form rust.

    This highly stain resistant alloy looks bright because of its ability to reflect light. It is

    used to make kitchen utensils, as stainless steel forms one of the most hygienic

    surfaces to store and prepare food in. Neither do they affect the flavor of the food, nor

    do they react with acidic foods during cooking. Moreover, since it has no pores in its

    surface it does not collect germs, dirt or grim, thereby making it very easy to clean.

    Besides cookware, stainless steel is also used for preparing surgical instruments,

    reinforcement bars, masonry support, washing machine drums, ships, chemical tankers,

    etc.

    Brass Alloy and its Uses

    Formed by a combination of zinc and copper, brass is a light yellowish to dark reddish

    brown colored alloy. The color range will deviate according to the amount of zinc

    present in brass. The higher the zinc content, the lighter will be the color. Brass is

    malleable, a good conductor of heat, resistant to salt water corrosion, etc. which is why

    it used to make items that come in contact with harsh environment such as tubes, pipes,weather stripping and several architectural trim pieces.

    Brass' excellent acoustic properties causes it to be used to make wind musical

    instruments. Instruments like euphonium, trombones, saxophone, tubas, horns, etc. are

    made from brass. Moreover, since brass does not tarnish easily, it is also used to make

    utensils, cutlery and other small decorative items. Its thermal conducting property

    makes it useful in the manufacture of radiators and heat exchangers such as oil coolers,

    air conditioners and heater cores.

    Sterling Silver Alloy and its UsesSilver in its purest form is malleable, ductile and extremely soft. This extreme softness

    makes it easy to work with, however, it also has its drawbacks. This causes silver to be

    scratched and deformed easily, thereby making it not suitable for manufacture of

    functional items. Thus, pure silver (92.5%) is combined with 7.5 % copper metal to

    get925 sterling silver. The copper metal gives silver, the ample strength required.

    Besides copper, even germanium, platinum and zinc can be added to the silver to form

    http://www.buzzle.com/articles/925sterling-silver-what-is-925sterling-silver.htmlhttp://www.buzzle.com/articles/925sterling-silver-what-is-925sterling-silver.htmlhttp://www.buzzle.com/articles/925sterling-silver-what-is-925sterling-silver.htmlhttp://www.buzzle.com/articles/925sterling-silver-what-is-925sterling-silver.html
  • 7/30/2019 Chemist Work

    28/54

    sterling silver.

    Sterling silver is used to make 925 silver jewelry.Another popular use of sterling silver is

    for the manufacture of tableware. Silver knives, spoons, forks, trays and tea sets are

    made and used by the higher class of people. Since sterling silver is naturally aseptic

    and is also resistant to antiseptics, heat sterilization and body fluids, it is used in the

    manufacture of medical instruments. Moreover, it is also used to make musical

    instruments like flute and saxophones.

    These were just three types of alloys and their uses. Alloys are truly beneficial because

    metals in their pure form are mostly very delicate to be used to make functional items.

    However, by alloy formation, we have been able to put all these metals to good use.

  • 7/30/2019 Chemist Work

    29/54

    4.0 POLYMERS

    4.1 Defination of Polymers

    A polymeris a large molecule (macromolecule) composed of repeating structural units.

    These sub-units are typically connected by covalent chemical bonds. Although thetermpolymeris sometimes taken to refer to plastics, it actually encompasses a large

    class of compounds comprising both natural and synthetic materials with a wide variety

    of properties.

    Because of the extraordinary range of properties of polymeric materials,[2]they play an

    essential and ubiquitous role in everyday life.[3]This role ranges from familiar

    synthetic plastics and elastomers to natural biopolymers such as nucleic

    acids and proteins that are essential for life.

    Natural polymeric materials such as shellac, amber, and natural rubberhave been used

    for centuries. A variety of other natural polymers exist, such as cellulose, which is the

    main constituent of wood and paper. The list of synthetic polymers includes synthetic

    rubber, Bakelite, neoprene, nylon, PVC, polystyrene, polyethylene, polypropylene,polya

    crylonitrile, PVB, silicone, and many more.

    Most commonly, the continuously linked backbone of a polymer used for the preparation

    of plastics consists mainly ofcarbon atoms. A simple example is polyethylene

    ('polythene' in British English), whose repeating unit is based on ethylene monomer.

    However, other structures do exist; for example, elements such as silicon form familiar

    materials such as silicones, examples being Silly Putty and waterproof plumbing

    sealant. Oxygen is also commonly present in polymer backbones, such as those

    ofpolyethylene glycol, polysaccharides (in glycosidic bonds),

    and DNA (in phosphodiester bonds).

    Polymers are studied in the fields ofpolymer chemistry, polymer physics, and polymer

    science.

    Diagram 1.3 branch point in polymer

    http://en.wikipedia.org/wiki/Moleculehttp://en.wikipedia.org/wiki/Macromoleculehttp://en.wikipedia.org/wiki/Structural_unithttp://en.wikipedia.org/wiki/Covalenthttp://en.wikipedia.org/wiki/Chemical_bondhttp://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Polymer#cite_note-PC1-1http://en.wikipedia.org/wiki/Polymer#cite_note-PC1-1http://en.wikipedia.org/wiki/Polymer#cite_note-PC1-1http://en.wikipedia.org/wiki/Polymer#cite_note-MBB1-2http://en.wikipedia.org/wiki/Polymer#cite_note-MBB1-2http://en.wikipedia.org/wiki/Polymer#cite_note-MBB1-2http://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Elastomerhttp://en.wikipedia.org/wiki/Biopolymershttp://en.wikipedia.org/wiki/Nucleic_acidhttp://en.wikipedia.org/wiki/Nucleic_acidhttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Natural_polymerhttp://en.wikipedia.org/wiki/Shellachttp://en.wikipedia.org/wiki/Amberhttp://en.wikipedia.org/wiki/Rubberhttp://en.wikipedia.org/wiki/Cellulosehttp://en.wikipedia.org/wiki/List_of_synthetic_polymershttp://en.wikipedia.org/wiki/Synthetic_rubberhttp://en.wikipedia.org/wiki/Synthetic_rubberhttp://en.wikipedia.org/wiki/Bakelitehttp://en.wikipedia.org/wiki/Neoprenehttp://en.wikipedia.org/wiki/Nylonhttp://en.wikipedia.org/wiki/PVChttp://en.wikipedia.org/wiki/Polystyrenehttp://en.wikipedia.org/wiki/Polyethylenehttp://en.wikipedia.org/wiki/Polypropylenehttp://en.wikipedia.org/wiki/Polyacrylonitrilehttp://en.wikipedia.org/wiki/Polyacrylonitrilehttp://en.wikipedia.org/wiki/Polyvinyl_butyralhttp://en.wikipedia.org/wiki/Siliconehttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Ethylenehttp://en.wikipedia.org/wiki/Monomerhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Silly_Puttyhttp://en.wikipedia.org/wiki/Polyethylene_glycolhttp://en.wikipedia.org/wiki/Polysaccharidehttp://en.wikipedia.org/wiki/Glycosidic_bondhttp://en.wikipedia.org/wiki/DNAhttp://en.wikipedia.org/wiki/Phosphodiester_bondhttp://en.wikipedia.org/wiki/Polymer_chemistryhttp://en.wikipedia.org/wiki/Polymer_physicshttp://en.wikipedia.org/wiki/Polymer_sciencehttp://en.wikipedia.org/wiki/Polymer_sciencehttp://en.wikipedia.org/wiki/Polymer_sciencehttp://en.wikipedia.org/wiki/Polymer_sciencehttp://en.wikipedia.org/wiki/Polymer_physicshttp://en.wikipedia.org/wiki/Polymer_chemistryhttp://en.wikipedia.org/wiki/Phosphodiester_bondhttp://en.wikipedia.org/wiki/DNAhttp://en.wikipedia.org/wiki/Glycosidic_bondhttp://en.wikipedia.org/wiki/Polysaccharidehttp://en.wikipedia.org/wiki/Polyethylene_glycolhttp://en.wikipedia.org/wiki/Silly_Puttyhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Monomerhttp://en.wikipedia.org/wiki/Ethylenehttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Siliconehttp://en.wikipedia.org/wiki/Polyvinyl_butyralhttp://en.wikipedia.org/wiki/Polyacrylonitrilehttp://en.wikipedia.org/wiki/Polyacrylonitrilehttp://en.wikipedia.org/wiki/Polypropylenehttp://en.wikipedia.org/wiki/Polyethylenehttp://en.wikipedia.org/wiki/Polystyrenehttp://en.wikipedia.org/wiki/PVChttp://en.wikipedia.org/wiki/Nylonhttp://en.wikipedia.org/wiki/Neoprenehttp://en.wikipedia.org/wiki/Bakelitehttp://en.wikipedia.org/wiki/Synthetic_rubberhttp://en.wikipedia.org/wiki/Synthetic_rubberhttp://en.wikipedia.org/wiki/List_of_synthetic_polymershttp://en.wikipedia.org/wiki/Cellulosehttp://en.wikipedia.org/wiki/Rubberhttp://en.wikipedia.org/wiki/Amberhttp://en.wikipedia.org/wiki/Shellachttp://en.wikipedia.org/wiki/Natural_polymerhttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Nucleic_acidhttp://en.wikipedia.org/wiki/Nucleic_acidhttp://en.wikipedia.org/wiki/Biopolymershttp://en.wikipedia.org/wiki/Elastomerhttp://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Polymer#cite_note-MBB1-2http://en.wikipedia.org/wiki/Polymer#cite_note-PC1-1http://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Chemical_bondhttp://en.wikipedia.org/wiki/Covalenthttp://en.wikipedia.org/wiki/Structural_unithttp://en.wikipedia.org/wiki/Macromoleculehttp://en.wikipedia.org/wiki/Molecule
  • 7/30/2019 Chemist Work

    30/54

    4.2 Natural Polymers

    Polymers in plant

    Plants are made of a polymer called cellulose. This is the tough stuff that wood and

    stems - and Paul's tree house! - are made from. Cellulose is also what makes fibers likecotton and hemp that we can twist into threads and weave into clothing. And many

    plants also make starch. Potatoes, corn, rice, and grains all have a lot of starch. Starch

    is also a polymer.

    Even though starch and cellulose are both made from the same sugar (glucose), they

    act very differently (because the glucose molecules are joined together differently).

    Starch will dissolve in water, but cellulose won't. So we make food from starches and

    we build things and make clothing out of cellulose.

    Starch is all twisted up in a tight blob, with lots of branches and ends sticking out all

    over. Starch is really just a compact way to store a lot of glucose in a small space. Our

    bodies break the starch down into glucose, which can be used for energy so you can

    run and jump and play and think.

    Plants use cellulose for strength. The cellulose chains are all stretched out, and like to

    stay tight right next to each other, like raw spaghetti that's all stuck together. That's why

    cellulose can hold up the tallest trees! And wooden houses too! Cotton is mostly

    cellulose - those stretched-out chains make great fibers.

    The cellulose in vegetables and grains is the fiber in our foods. We can't digest it, but it's

    good for us because it helps keep our insides clean.

    Cellulose and starches are both made from sugars - so they're called polysaccharides

    (meaning "many sugars").

    Another useful natural polymer produced by plants is rubber. It has been harvested from

    trees in Central and South America for hundreds of years. In the last couple hundred

    years people have figured out ways to make it stronger and more durable. And

    scientists have been very successful in inventing their own versions of rubber for

    different purposes.

    http://www.pslc.ws/macrog/kidsmac/cell.htmhttp://www.pslc.ws/macrog/kidsmac/starch.htmhttp://start%28%27sugar.htm%27%29/http://www.pslc.ws/macrog/kidsmac/fiber.htmhttp://www.pslc.ws/macrog/kidsmac/rubber.htmhttp://www.pslc.ws/macrog/kidsmac/rubber.htmhttp://www.pslc.ws/macrog/kidsmac/fiber.htmhttp://start%28%27sugar.htm%27%29/http://www.pslc.ws/macrog/kidsmac/starch.htmhttp://www.pslc.ws/macrog/kidsmac/cell.htm
  • 7/30/2019 Chemist Work

    31/54

    Polymers in people Protein

    You know they say "You are what you eat." Well, one natural polymer that we eat a lot

    of is also one we are made of - PROTEIN! Protein also forms some of the things you

    wear - namely leather, silk, and wool. Protein is a natural polymer formed from

    molecules called amino acids. Chicken nuggets and hamburgers have a lot of protein(but the bun has a lot of starch!). Protein is the main thing in skin, organs, muscles, hair

    and fingernails. The most common protein in your body,collagen, is used for support

    and structure. It's in-between all the cells in your body, all around your organs, even in

    your teeth and bones.Feathers and fur, hair and fingernails (even animal hooves), are

    all made of the protein keratin. Wool is made from sheep hair, and is great for clothing

    and fabric. Wool is warm and sometimes a little itchy, but it's still widely used. You'll find

    it everywhere from hats to skirts to the inside of a piano... and of course in sweaters. In fact

    many kinds of animal hair besides wool have been used to make clothing. Angora rabbits have

    extra light, soft, fluffy fur. Cashmere is a wool that comes from special goats, and is very soft

    and long-wearing. Alpacas and llamas also produce wool that's soft and warm.

    Silk

    nother great protein is silk - a sort of fiber made by special caterpillars. This stuff has

    been used for thousands of years to make beautiful fabric for clothing. And though

    people have made their own version of silk called nylon, there's still nothing out there

    quite like silk. Spider silk is incredibly strong for its weight, and scientists have been

    working hard to mimic this fiber, too.

    Enzyme

    A special group of proteins that work inside the body are enzymes. Each enzyme is a

    specific little glob of a protein that does a specific job in the body, and does it really

    really fast. Without enzymes, these jobs either just wouldn't happen, or would go way

    too slowly to make life possible! Some enzymes even make other enzymes. The

    enzymes all work together to keep everything in your body going, like processing your

    food into energy so you can chase your little brother around. Click here to see how youcan taste enzymes working.

    http://start%28%27leather.htm%27%29/http://www.pslc.ws/macrog/kidsmac/protein.htmhttp://start%28%27amino.htm%27%29/http://start%28%27collagen.htm%27%29/http://start%28%27keratin.htm%27%29/http://start%28%27llamas.htm%27%29/http://start%28%27cracker.htm%27%29/http://start%28%27cracker.htm%27%29/http://start%28%27llamas.htm%27%29/http://start%28%27keratin.htm%27%29/http://start%28%27collagen.htm%27%29/http://start%28%27amino.htm%27%29/http://www.pslc.ws/macrog/kidsmac/protein.htmhttp://start%28%27leather.htm%27%29/
  • 7/30/2019 Chemist Work

    32/54

    4.3 Synthetic Polymers

    History of Synthetic Polymers:-

    While polymers form the basis of life, the history of synthetic polymers is relativelyrecent. Some of the key polymers that have been developed since the early days of

    polymer science include:

    Vulcanized rubber. In the mid-1800s, American scientist Charles Goodyear began

    working with rubber to try to make it more temperature stable. After many unsuccessful

    attempts, he accidentally allowed a mixture of sulfur and pre-rubber to touch a hot

    stove. The rubber did not melt but only charred a little. By 1844 Goodyear had been

    given a patent for a process he called "vulcanization" after the Roman god of fire,

    Vulcan. Vulcanization is the crosslinking reaction between the rubber chains and the

    sulfur.

    Bakelite.After years of work in his chemistry lab in Yonkers, New York, Leo Baekeland

    announced in 1907 the synthesis of the first truly synthetic polymeric material, later

    dubbed "Bakelite." It was generally recognized by leading organic chemists of the

    nineteenth century that phenol would condense with formaldehyde, but because they

    did not understand the principles of the reaction, they produced useless crosslinked

    materials. Baekeland's main project was to make hard objects from phenol and

    formaldehyde and then dissolve the product to reform it again in a desired shape. He

    circumvented the problem by placing the reactants directly in a mold of the desired

    shape and then allowing the reactants to form a hard, clear solidBakelite (Figure 15).

    It could be worked (i.e., cut, drilled, and sanded), was resistant to acids and organic

    liquids, was stable at high temperatures, and did not break down when exposed to

    electrical charge. By adding dyes to the starting materials the objects became available

    in different colors. Bakelite was used to make bowling balls, phonograph records,

    telephone housings, cookware, and billiard balls. Bakelite also acted as a binder for

    textiles, sawdust, and paper, forming a wide range of composites including Formica

    laminates. Many of these combinations are still in use in the twenty-first century.

  • 7/30/2019 Chemist Work

    33/54

    Neoprene. Chemist and Catholic priest Julius A. Nieuwland did extensive work in the

    1920s on acetylene. He found that acetylene could be made to add to itself forming

    dimers and trimers. Arnold Collins, a chemist at the Dupont Company in the lab of

    Wallace Carothers, continued work on the project and in 1930 ran the reaction

    described by Nieuwland, purifying the reaction mixture. He found a small amount of

    material that was not vinylacetylene or divinylacetylene. After setting the liquid aside, it

    solidified into a material that seemed rubbery and even bounced. This new rubber was

    given the name Neoprene (figure 1.2). Neoprene has outstanding resistance to

    gasoline, ozone, and oil in contrast to natural rubber and is used in a variety of

    applications including electrical cable jacketing, window gaskets, shoe soles, industrial

    hose, and heavy-duty drive belts.

    figure 1.2 Neoprene

    Nylon. In the early 1930s Wallace Carothers and his team of chemists at Dupont were

    investigating synthetic fibers in order to find a synthetic alternative to silk. Onepromising candidate was formed from the reaction of adipic acid with

    hexamethylenediamine and was called fiber 66 because each monomer-containing unit

    had six carbons. It formed a strong, elastic, largely insoluble fiber with a relatively high

    melting temperature. DuPont chose this material for production. Such polyamides were

    given the name "nylons"; thus was born nylon 6,6 (Figure 1.3).

    Figure 1.3 Nylon

  • 7/30/2019 Chemist Work

    34/54

    Poly(vinyl chloride). While PVC was initially formed by German chemist Eugen

    Baumann in 1872, scientists at B. F. Goodrich discovered in 1926 how to make sheets

    and adhesives from it, starting the "vinyl age." PVC's many applications include water

    pipes and joints, building materials, food packaging, wire insulation, and medical

    components.

    Polystyrene. While polystyrene was probably first formed by German apothecary

    Eduard Simon in 1839, it was almost 100 years later, in 1930, that the German chemical

    company I. G. Fraben placed polystyrene on the market. Polystyrene-molded parts

    became common place by 1935. Applications of polystyrene include loose-fill packaging

    "peanuts," shape-molded packaging, and disposable utensils.

    Polyacrylonitrile. Rohm and Haas Company bought out Plexiglas (polyacrylonitrile

    [Figure 1.4]; also known as acrylic and as a fiber sold under tradenames such as Orlon)

    from a British firm in 1935 and began production of clear plastic parts and goods,

    including replacements for glass in camera lenses, aircraft windows, clock faces, andcar tail lights.

    figure 1.4 PVC

    Type of Synthetic Polymers

    Elastomers. Elastomers are polymers possessing chemical and/or physical crosslinks

    (Table 1 and 2). These crosslinks allow the stretched, deformed segments to return to

    their original locations after the force is removed. The "use" temperature must be above

    the T g to allow ready chain slippage as the rubbery material is flexed and extended.

    The forces between the chains should be minimal to allow easy movement of these

    chain segments. Finally, the chains must be present in an amorphous, disorganizedfashion. As force is applied and the material distorts or elongates, the randomly oriented

    chains are forced to align and take more ordered positions with the chains, forming

    crystalline regions that resist ready movement. As the force is removed the material has

    a tendency to return to its original disorganized state and therefore its pre-stretched

    shape. The formation of the crystalline regions as the material is stretched gives the

    material a greater tensile strength(i.e. an increased force is necessary for further

  • 7/30/2019 Chemist Work

    35/54

    elongation) at high extensions. Crosslinked vinyl polymers are ideal materials to be

    used in elastomers: the attractive forces between chains is low and their T g is below

    room temperature.

    Thermosets and thermoplastics. Thermosets are materials that have sufficient

    crosslinking present so that they are prevented from being soluble and melting whenheated. Such materials are therefore difficult to recycle. Thermoplastics are materials

    that melt on heating and generally contain little or no crosslinking. They can be recycled

    more easily through heating and reforming. Linear polymers are thermoplastic

    materials.

    Fibers. Fibers require materials with a high tensile strength and high modulus (high

    force required for elongation). This requires polymers with strong forces between the

    chains and chains that are symmetrical to allow for good crystalline formation.

    Condensation polymers exhibit these properties and so are most utilized as fibers.

    Fibers are normally linear and drawn (pulled) in one direction, producing highermechanical properties in that direction. If the fiber is to be ironed, its T g should be

    above 200oC. Branching and crosslinking are undesirable since they inhibit crystalline

    formation. Even so, some crosslinking may be present to maintain a given orientation,

    such as desired in permanent press clothing. While most fibers are made from

    condensation polymers, new treatments allow some fibers to be made from olefinic

    materials such as polypropylene.

  • 7/30/2019 Chemist Work

    36/54

    4.4 Synthetic Polymers in Daily Life

    Polymers are a part of our every day life and without them around, this world would be

    very, very different, if not impossible to live in. However, most people do not even knowwhat a polymer is, or just how widespread they are around us. Polymers are formed

    from hydrocarbons, hydrocarbon derivatives, or sometimes from silicon. They are the

    basis not only for numerous natural materials, but also for most of the synthetic plastics

    that one encounters in their lives. Polymers consist of extremely large, chain-like

    molecules that are, in turn, made up of numerous smaller, repeating units called

    monomers.

    There are a few different types of polymers that exist. There are natural polymers, which

    consist of wool, hair, rubber, etc., as well as many synthetic polymers which would

    include nylon, synthetic rubber, polyester, Teflon, and so forth. Polymers are

    everywhere, so much so that it is very difficult to spend a day without encountering anatural polymer, even if hair is removed from the list.

    In fact, in the day and age that we live in, it is probably even harder to avoid synthetic

    polymers, which have together revolutionized our society.

    There are many polymers that exist in nature, such as silk, cotton, starch, sand, and

    yes, even asbestos. There are even more complex natural polymers that are incredibly

    complex, such as a persons DNA (deoxyribonucleic acid), which hold genetic codes.

    Synthetic (artificial) polymers, which will be the focal point of the paper, would include

    plastics like Styrofoam and Saran wrap; fibers such as nylon and Dacron (polyester);

    and other materials such as Formica, Teflon, and PVC pipe.Polymers are all around us, but lets make this thought of polymers more real to us, and

    imagine the typical day of a hypothetical teenage girl. She wakes up, and is so

    comfortable in her nice warm bed with the sheets all around her. Chances are that

    those sheets she has on her consist of tons of polymers. Then she finally gets up and

    out of bed, and.

  • 7/30/2019 Chemist Work

    37/54

    5.0 GLASS AND CERAMICS

    5.1 Defination of Glass and Ceramics

    Defination of Glass

    Glass is an amorphous (non-crystalline) solid material. Glasses are typically brittle and

    optically transparent.

    The most familiar type of glass, used for centuries in windows and drinking vessels,

    is soda-lime glass, composed of about 75% silica (SiO2) plus Na2O, CaO, and several

    minor additives. Often, the term glass is used in a restricted sense to refer to this

    specific use.

    In science, however, the term glass is usually defined in a much wider sense, including

    every solid that possesses a non-crystalline (i.e., amorphous) structure and that exhibits

    a glass transition when heated towards the liquid state. In this wider sense, glasses can

    be made of quite different classes of materials: metallic alloys, ionic melts, aqueous

    solutions, molecular liquids, and polymers. For many applications (bottles, eyewear)

    polymer glasses (acrylic glass, polycarbonate,polyethylene terephthalate) are a lighter

    alternative to traditional silica glasses.

    Defination of Ceramics

    A ceramic is an inorganic, nonmetallic solid prepared by the action ofheat and

    subsequent cooling.[1]Ceramic materials may have a crystalline or partly crystalline

    structure, or may be amorphous (e.g., a glass). Because most common ceramics arecrystalline, the definition of ceramic is often restricted to inorganic crystalline materials,

    as opposed to the noncrystalline glasses.

    The earliest ceramics were pottery[citation needed]

    objects or27,000 year old figurines made

    from clay, either by itself or mixed with other materials, hardened in fire. Later ceramics

    were glazed and fired to create a colored, smooth surface. Ceramics now include

    domestic, industrial and building products and art objects. In the 20th century,

    new ceramic materials were developed for use in advanced ceramic engineering; for

    example, in semiconductors.

    The word "ceramic" comes from the Greek word (keramikos), "of pottery" or

    "for pottery",[2]from (keramos), "potter's clay, tile, pottery".[3]The earliest

    mention of the root "ceram-" is the Mycenaean Greek ke-ra-me-we, "workers of

    ceramics", written in Linear b syllabic script.[4]"Ceramic" may be used as an adjective

    describing a material, product or process; or as a singular noun, or, more commonly, as

    a plural noun, "ceramics".[5]

    http://en.wikipedia.org/wiki/Amorphous_solidhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Brittlehttp://en.wikipedia.org/wiki/Transparency_and_translucencyhttp://en.wikipedia.org/wiki/Windowhttp://en.wikipedia.org/wiki/List_of_glasswarehttp://en.wikipedia.org/wiki/Soda-lime_glasshttp://en.wikipedia.org/wiki/Silicon_dioxidehttp://en.wikipedia.org/wiki/Sodium_oxidehttp://en.wikipedia.org/wiki/Sodium_oxidehttp://en.wikipedia.org/wiki/Sodium_oxidehttp://en.wikipedia.org/wiki/Calcium_oxidehttp://en.wikipedia.org/wiki/Amorphous_solidhttp://en.wikipedia.org/wiki/Glass_transitionhttp://en.wikipedia.org/wiki/Alloyshttp://en.wikipedia.org/wiki/Aqueous_solutionshttp://en.wikipedia.org/wiki/Aqueous_solutionshttp://en.wikipedia.org/wiki/Polymershttp://en.wikipedia.org/wiki/Glass_Bottleshttp://en.wikipedia.org/wiki/Eyewear_(disambiguation)http://en.wikipedia.org/wiki/Acrylic_glasshttp://en.wikipedia.org/wiki/Polycarbonatehttp://en.wikipedia.org/wiki/Polyethylene_terephthalatehttp://en.wikipedia.org/wiki/Inorganichttp://en.wikipedia.org/wiki/Nonmetalhttp://en.wikipedia.org/wiki/Solidhttp://en.wikipedia.org/wiki/Heathttp://en.wikipedia.org/wiki/Ceramic#cite_note-0http://en.wikipedia.org/wiki/Ceramic#cite_note-0http://en.wikipedia.org/wiki/Ceramic#cite_note-0http://en.wikipedia.org/wiki/Crystallinehttp://en.wikipedia.org/wiki/Amorphoushttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Potteryhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Venus_of_Doln%C3%AD_V%C4%9Bstonicehttp://en.wikipedia.org/wiki/Figurinehttp://en.wikipedia.org/wiki/Clayhttp://en.wikipedia.org/wiki/Ceramic_arthttp://en.wikipedia.org/wiki/Ceramic_materialshttp://en.wikipedia.org/wiki/Ceramic_engineeringhttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Greek_languagehttp://en.wikipedia.org/wiki/Ceramic#cite_note-1http://en.wikipedia.org/wiki/Ceramic#cite_note-1http://en.wikipedia.org/wiki/Ceramic#cite_note-1http://en.wikipedia.org/wiki/Ceramic#cite_note-2http://en.wikipedia.org/wiki/Ceramic#cite_note-2http://en.wikipedia.org/wiki/Ceramic#cite_note-2http://en.wikipedia.org/wiki/Mycenaean_Greekhttp://en.wikipedia.org/wiki/Linear_bhttp://en.wikipedia.org/wiki/Ceramic#cite_note-3http://en.wikipedia.org/wiki/Ceramic#cite_note-3http://en.wikipedia.org/wiki/Ceramic#cite_note-3http://en.wikipedia.org/wiki/Ceramic#cite_note-4http://en.wikipedia.org/wiki/Ceramic#cite_note-4http://en.wikipedia.org/wiki/Ceramic#cite_note-4http://en.wikipedia.org/wiki/Ceramic#cite_note-4http://en.wikipedia.org/wiki/Ceramic#cite_note-3http://en.wikipedia.org/wiki/Linear_bhttp://en.wikipedia.org/wiki/Mycenaean_Greekhttp://en.wikipedia.org/wiki/Ceramic#cite_note-2http://en.wikipedia.org/wiki/Ceramic#cite_note-1http://en.wikipedia.org/wiki/Greek_languagehttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Ceramic_engineeringhttp://en.wikipedia.org/wiki/Ceramic_materialshttp://en.wikipedia.org/wiki/Ceramic_arthttp://en.wikipedia.org/wiki/Clayhttp://en.wikipedia.org/wiki/Figurinehttp://en.wikipedia.org/wiki/Venus_of_Doln%C3%AD_V%C4%9Bstonicehttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Potteryhttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Amorphoushttp://en.wikipedia.org/wiki/Crystallinehttp://en.wikipedia.org/wiki/Ceramic#cite_note-0http://en.wikipedia.org/wiki/Heathttp://en.wikipedia.org/wiki/Solidhttp://en.wikipedia.org/wiki/Nonmetalhttp://en.wikipedia.org/wiki/Inorganichttp://en.wikipedia.org/wiki/Polyethylene_terephthalatehttp://en.wikipedia.org/wiki/Polycarbonatehttp://en.wikipedia.org/wiki/Acrylic_glasshttp://en.wikipedia.org/wiki/Eyewear_(disambiguation)http://en.wikipedia.org/wiki/Glass_Bottleshttp://en.wikipedia.org/wiki/Polymershttp://en.wikipedia.org/wiki/Aqueous_solutionshttp://en.wikipedia.org/wiki/Aqueous_solutionshttp://en.wikipedia.org/wiki/Alloyshttp://en.wikipedia.org/wiki/Glass_transitionhttp://en.wikipedia.org/wiki/Amorphous_solidhttp://en.wikipedia.org/wiki/Calcium_oxidehttp://en.wikipedia.org/wiki/Sodium_oxidehttp://en.wikipedia.org/wiki/Silicon_dioxidehttp://en.wikipedia.org/wiki/Soda-lime_glasshttp://en.wikipedia.org/wiki/List_of_glasswarehttp://en.wikipedia.org/wiki/Windowhttp://en.wikipedia.org/wiki/Transparency_and_translucencyhttp://en.wikipedia.org/wiki/Brittlehttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Amorphous_solid
  • 7/30/2019 Chemist Work

    38/54

    5.2 Types, Composition, Properties and Uses of Glass

    Types

    When people speak of glass, they ordinarily mean a transparent, shiny substance that

    breaks rather easily. They may think of the glass in windows and the glass used in

    eyeglasses as being the same material. Actually, they are not. There are many kinds of

    glass. Several important kinds of glass are discussed in this article.

    Flat glass is used chiefly in windows. It is also used in mirrors, room dividers, and some

    kinds of furniture. All flat glass is made in the form of flat sheets. But some of it, such as

    that used in automobile windshields, is reheated and sagged(curved) over molds.

    Glass containers are used for packaging food, beverages, medicines, chemicals, and

    cosmetics. Glass jars and bottles are made in a wide variety of shapes, sizes, and

    colors. Many are for common uses, such as soft-drink bottles or jars for home canning.

    Others are made from special glass formulas to make sure there will be no

    contamination or deterioration of blood plasma, serums, and chemicals stored in them.

    See .

    Optical glass is used in eyeglasses, microscopes, telescopes, camera lenses, and

    many instruments for factories and laboratories. The raw materials must be pure so that

    the glass can be made almost flawless. The care required for producing optical glass

    makes it expensive compared with other kinds of glass.

    Fiberglass consists of fine but solid rods of glass, each of which may be less than one-

    twentieth the width of a human hair. These tiny glass fibers can be loosely packed

    together in a woollike mass that can serve as heat insulation. They also can be used

    like wool or cotton fibers to make glass yarn, tape, cloth, and mats. Fiberglass has

    many other uses. It is used for electrical insulation, chemical filtration, and firefighters'

    suits. Combined with plastics, fiberglass can be used for airplane wings and bodies,

    automobile bodies, and boat hulls. Fiberglass is a popular curtain material because it is

    fire-resistant and washable.

    Laminated safety glassis a sandwich made by combining alternate layers of flat

    glass and plastics. The outside layer of glass may break when struck by an object, but

    the plastic layer is elastic and so it stretches. The plastic holds the broken pieces of

    glass together and keeps them from flying in all directions. Laminated glass is used

    where broken glass might cause serious injuries, as in automobile windshields.

  • 7/30/2019 Chemist Work

    39/54

    Bullet-resisting glass is thick, multilayer laminated glass. This glass can stop even

    heavy-caliber bullets at close range. Bullet-resisting glass is heavy enough to absorb

    the energy of the bullet, and the several plastic layers hold the shattered fragments

    together. Such glass is used in bank teller windows and in windshields for military tanks,

    aircraft, and special automobiles.

    Tempered safety glass, unlike laminated glass, is a single piece that has been given a

    special heat treatment. It looks, feels, and weighs the same as ordinary glass. But it can

    be several times stronger. Tempered glass is used widely for all-glass doors in stores,

    side and rear windows of automobiles, and basketball backboards, and for other special

    purposes. It is hard to break even when hit with a hammer. When it does break, the

    whole piece of glass collapses into small, dull-edged fragments.

    Colored structural glass is a heavy plate glass, available in many colors. It is used in

    buildings as an exterior facing, and for interior walls, partitions, and tabletops.

    Opal glass has small particles in the body of the glass that disperse the light passing

    through it, making the glass appear milky. The ingredients necessary to produce opal

    glass include fluorides (chemical compounds containing fluorine). This glass is widely

    used in lighting fixtures and for tableware.

    Foam glass, when it is cut, looks like a black honeycomb. It is filled with many tiny cells

    of gas. Each cell is surrounded and sealed off from the others by thin walls of glass.

    Foam glass is so light that it floats on water. It is widely used as a heat insulator in

    buildings, on steam pipes, and on chemical equipment. Foam glass can be cut into

    various shapes with a saw.

    Glass building blocks are made from two hollow half-sections sealed together at a

    high temperature. Glass building blocks are good insulators against heat or cold

    because of the dead-air space inside. The blocks are laid like bricks to make walls and

    other structures.

    Heat-resistant glass is high in silica and usually contains boric oxide. It expands little

    when heated, so it can withstand great temperature changes without cracking. This

    quality is necessary in cookware and other household equipment, and in many types of

    industrial gear.

    Laboratory glassware includes beakers, flasks, test tubes, and special chemical

    apparatus. It is made from heat-resistant glass to withstand severe heat shock(rapid

    change in temperature). This glass is also much more resistant to chemical attack than

    ordinary glass.

  • 7/30/2019 Chemist Work

    40/54

    Glass for electrical uses. Glass has properties that make it useful in electrical

    applications: ability to resist heat, resistance to the flow of electric current, and ability to

    seal tightly to metals without cracking. Because of these properties, glass is used in

    electric light bulbs and for picture tubes in television sets.

    Glass optical fibers are glass fibers used to transmit information as pulses of light.Thin, extremely pure optical fibers are used to carry telephone and television signals

    and digital(numeric) data over long distances. Glass optical fibers are also used in

    control board displays and in medical instruments.

    Glass tubing is used to make fluorescent lights, neon signs, glass piping, and chemical

    apparatus. Glass tubing is made from many kinds of glass and in many sizes.

    Glass-ceramics are strong materials made by heating glass to rearrange some of its

    atoms into regular patterns. These partially crystalline materials can withstand high

    temperatures, sudden changes in temperature, and chemical attacks better thanordinary glass can. They are used in a variety of products, including heat-resistant

    cookware, turbine engines, electronic equipment, and nose cones of guided missiles.

    Glass-ceramics have such trade names as Pyroceram, Cervit, and Hercuvit.

    Radiation-absorbing and radiation-transmitting glass can transmit, modify, or block

    heat, light, X rays, and other types of radiant energy. For example, ultraviolet glass

    absorbs the ultraviolet rays of the sun but transmits visible light. Other glass transmits

    heat rays freely but passes little visible light. Polarized glass cuts out the glare of

    brilliant light. One-way glass is specially coated so that a person can look through a

    window without being seen from the other side.

    Laser glass is an optical glass containing small amounts of substances that enable the

    glass to generate laser beams efficiently. Such glass is used as the active medium

    in solid-state lasers, a type of laser that sends light out through crystals or glass (One

    substance commonly used in laser glass is the element neodymium. Researchers are

    using glass lasers in an attempt to harness nuclear fusion (the joining of atomic nuclei)

    as a source of commercially useful amounts of energy. In their experiments, powerful

    glass lasers heat hydrogen atoms until hydrogen nuclei fuse, releasing large amounts of

    energy.

    "Invisible glass" is used principally for coated camera lenses and eyeglasses. The

    coating is a chemical film that decreases the normal loss of light by reflection. This

    allows more light to pass through the glass.

    Photochromic glass darkens when exposed to ultraviolet rays and clears up when the

    rays are removed. Photochromic glass is used for windows, sunglasses, and instrument

    controls.

  • 7/30/2019 Chemist Work

    41/54

    Photosensitive glass can be exposed to ultraviolet light and to heat so that any pattern

    or photograph can be reproduced within the body of the glass itself. Because the

    photographic print then becomes an actual part of the glass, it will last as long as the

    glass itself.

    Photochemical glass is a special composition of photosensitive glass that can be cutby acid. Any design can be reproduced on the glass from a photographic film. Then

    when the glass is dipped in acid, the exposed areas are eaten away, leaving the design

    in the glass in three dimensions. By this means, lacelike glass patterns can be made.

    Heavy metal fluoride glass is an extremely transparent glass being developed for use

    in optical fibers that transmit infrared rays. Infrared rays are much like light waves but

    are invisible to the human eye. In optical fibers, infrared light transmits better over

    distance than visible light does.

    Chalcogenide glass is made up of elements from the chalcogen group, includingselenium, sulfur, and tellurium. The glass is transparent to infrared light and is useful as

    a semiconductor in some electronic devices. Chalcogenide glass fibers are a

    component of devices used to perform laser surgery.

    Sol-Gel glass can be used as a protective coating on certain solar collectors or as an

    insulating material. It is also used to make short, thick tubes that are drawn into optical

    fibers. To make Sol-Gel glass, workers dissolve the ingredients in a liquid. They then

    heat the liquid. The liquid evaporates, leaving behind small particles of glass. Heating

    these particles fuses (joins) them to form a solid piece of glass. The temperatures

    involved in Sol-Gel processes are often lower than those needed to make ordinaryglass.

  • 7/30/2019 Chemist Work

    42/54

    Composition of Glass

    Figure 1.5 composition of typical glass container

    The primary constituent making up the chemical composition of glass is silica (silicon

    dioxide), which is the most common component of the earth's crust and accounts for 50-

    70% of the weight of ancient glass (Freestone 1991). The silica is extracted from raw

    materials as freely available as quartz sand, white quartz pebbles and flint. The

    metallurgical furnaces and pottery kilns utilised in ancient times were not, however,

    capable of heating crushed quartz pebbles to the temperatur