Flux+ impurity

Tin

Carbon monoxide

Zinc coating

Methane (CH4)

Less

Extender

Vinyl chloride

Compressed natural gas (CNG)

Decibel (db)

True

False

True

True

False

This method is used for concentration of sulphide ores of copper, zinc and lead. In this method, powdered ore is put in a tank full of water. And then, some Pine oil is added to it. In the tank, the particles of sulphide ores wetted by pine oil whereas the gangue (impurities like rock particles, sand, etc.) particles are wetted by water. Then air is passed through this mixture. This results in the agitation of water in tank. Which cause the sulphide ore particles to stick with the oil and rise to the surface in the form of the froth? The gangue particle being heavier remains behind at the bottom of water tank. The froth is separated and concentrated sulphide ore is obtained from it.

Metal cladding is a type of protective coating, where the protective metal such as metal powder or foil is bonded to a sub state by applying heat and/or pressure. The study of metal cladding is significant because this method of corrosion protection and wear protection is generally very reliable and cost effective.
 Metal spraying is a process for covering a surface with a metallic coating using a spray of molten particle. This process can also be labelled with a more general term ‘thermal spraying’.

Producer gas is a mixture of flammable gases (principally CO2 and H2) and non-flammable gases(N2 and CO2) made by the partial combustion of carbonaceous substances, usually coal, an atmosphere of air and steam. Producer gas has lower heating value than other gaseous fuels, but it can be manufactured with relatively simple equipment; it is used mainly as a fuel in large industrial furnaces.
Composition

CO2, O2, CO, H2, CH4, N2

Uses:-
Producer gas was used primarily as an industrial fuel for iron & steel. Manufacturing such as firing coke ovens & blast furnaces, cement & ceramic kilns, or for mechanical power through gas engines.

Uses of Lubricants:-
(i)    A lubricant reduces friction & prevents heating.
(ii)    It is used for load balancing.
(iii)    Long term use of systems may lead to corrosion, therefore, lubricant is used for cleaning it.
(iv)    It is used for sealing the macro gaps between the systems.
(v)    It is used for rust prevention.

Applications of polymers:-
(1)    Polymers are used in aerospace & aircraft.
(2)    Polymers are used in biomedical like in drug delivery system, biosensor devices, tissue engineering and in other systems.
(3)    They are used in fibers, coatings, rubbers, sealing material, solvents & adhesive resins.
(4)    They are also used in holography.
(5)    They are used in making bulletproof & fire resistant jackets.

Main sources of air pollution:-
(1)    Burning of fossil fuels in electricity generation, transport, industry and house hold.
(2)    Industrial processes & solvent use for eg. In chemical & mining industries.
(3)    By agriculture.
(4)    Natural sources including volcano eruptions, windblown dust & emission of volatile organic compounds from plastics.

Erosion is the process that describes continuous physical & chemical events which cause the soil & rocks on earth surface to loosen & make the new location.
Both corrosion & erosion happens due to certain external actions on a surface.
Corrosion means the destruction of materials through chemical reactions & erosion means carrying away the top soil from the surface of the earth.

(1) Bronze is one of the earliest metals known to man. It is defined as an alloy made of copper and another metal, usually tin. Compositions vary but most modern bronze is 88 % copper (Cu) & 12 % tin (Sn). Bronze may also contain Manganese (Mn), aluminium (Al), Nickel (Ni), Phosphorous (P), Silicon (Si), Arsenic (As) or Zinc (Zn).
Uses:-
i)    Bronze is used in ship propellers & submerged bearings owing to the combination of toughness & resistance to salt water corrosion.
ii)    Phosphor bronze is particularly suited to bearing clips, electrical connections & springs.
iii)    It is used to make hammers wrenches & other double tools to be used in explosive atmosphere or in the presence of flammable vapours.
iv)    It is preferred metal for top quality bells.
v)    It is used in manufacture of various types of metals.
vi)    It is used in furniture hardware.

(2) Gun Metal:- It is occasionally called red brass in the US. It is an alloy made from Copper (Cu), Zinc (Zn)& Tin (Sn). Aside from its basic constituents modified forms may have nickel & lead which are classified as nickel gunmetal & leaded gunmetal. Chemical composition of gun metal is 88 % copper, 10 Tin & 2 % Zinc.
Uses: 
i)    It is used in manufacturing of pipe fitting, Valves & pumps.
ii)    It is used for making statues.
iii)    Bearings, where speeds & load are moderate, are manufactured from gunmetal & used in machinery.

The process of slowly eating away of the metal due to attack of the moisture & atmospheric gases on the surface of the metal resulting into formation of compound such as oxides, sulphides, carbonates, sulphates is called corrosion.

The phenomenon of corrosion can be described as

At anode:

Fe(s) undergoes oxidation to release electrons

Fe(s)    →     Fe²⁺(aq) + 2e^-

At cathode:

O₂(g) + 4H⁺ + 4e^-        →     2H₂O(e)

Electrons released at anode move to another metal & reduce oxygen in the presence of H+. It is available from H₂CO₃ formed from the dissolution of CO₂ from air into water H+ in water may be available also through dissolution of other acidic oxides from the atmosphere.

Net reaction:

Fe(s) +2H⁺(aq)+1/2 O₂(g) ^-        →      Fe²⁺(aq) + H₂O(g)

Fe2+ again gets oxidised to form rust.

Fe(s) +2H⁺(aq)+1/2 O₂(g) ^-        →      Fe₂O₃(s) + 4H⁺

                                                                                (Rust)

Fuel:- Fuel is any substance that can provide heat and produce energy when it is burnt. This energy that releases is generally in the form of chemical energy or heat energy. The recent invention of nuclear technology means now even nuclear energy may be released due to nuclear fission or fusion.

  The heat energy that fuels release is used for various purpose such as cooking, in heaters and for many other purposes. At other times we use an engine to convert this heat into mechanical energy like when we use petrol to run our cars.

Characteristics of a good fuel:-

1) It is less expensive.
2) It does not leave behind any undesirable substance.
3) It can be transported easily.
4) It is readily available.
5) It burns easily at moderate rate.
6) It has high calorific value.

Fire point:- It is the lowest point at which a volatile combustible substance continues to burn in the air after its vapors have been ignited as when heating is continued after the flash point has been determined.

Flash point:- The temperature at which fuel oil gives off vapour that flashes when exposed to an open flame.
Viscosity:- It is the quantity that describes a fluid’s resistance to flow. Fluids resist the relative motion of immersed objects through them as well as to the motion of layers with differing velocities  within them it is represented by ɳ  (‘eta’). Which is equal to the ratio of shearing stress (F/A) to the velocity gradient () in a fluid.

i.e.   

Viscosity index:- temperature plays an important role in a fluid’s viscosity,  so the world needed a way to measure it with change in the temperature. “The viscosity index is a measure of change in viscosity with fluctuations in temperature”. In simpler terms, the viscosity index tells you how well fluid can protect its viscosity during change in temperature.

Cloud point:- It is temperature above which an aqueous solution of a water-soluble surfactant becomes turbid (opaque).

Pour point:- It is the temperature at which a liquid becomes semisolid and loses its flowing characteristics.

Glass is an amorphous solid. Glass does not have any crystalline structure. They usually are hard and brittle solids. Glass is the name given to any amorphous solid that displays a “glass transition” near its melting point. This is related to the glass transition temperature, which is the temperature where an amorphous solid becomes soft near its melting point or a liquid becomes brittle near its freezing point.
Composition of glass:- 
                   Silicon dioxide (SiO₂)
                   Limestone Or calcium carbonate (CaCO₃)
                   Sodium carbonate (Na₂CO₃)
Uses:- 
1.    Packaging jars for food, bottles for drinks, etc.)
2.    Tableware (drinking glasses, plates, cups, etc.)
3.    Housing and buildings (windows, facades, reinforcement structure)
4.    Interior design and furniture (mirrors, partitions, lighting, etc.)
5.    Appliances and electronics (oven doors, T.V., computer screens, etc.)
6.    Automotive and transport
7.    Fibre optic cables
8.    Medical technology
9.    Renewable energy (Solar energy glasses, wind turbines).

Lubricants is a substance which is used to control (more often to reduce) friction and wear of the surfaces in a contact of the bodies in relative motion. A lubricant can be in liquid(oil, water, etc.); solid(graphite, grapheme, etc.); gaseous(air) or even semi-solid (grease) forms.
Classification of lubricants:-
●    Liquid lubricants: All liquid lubricants, including minerals, natural or synthetic oil, emulsions, etc.
●    Solid lubricants: All lubricants in solid form including powder, coatings and composites. (graphite, grapheme, molybdenum disulphide, etc.)
●    Gaseous lubricants: Typically its air, but can be other gas.
●    Semi-solid: Greases, generally consists of soap emulsified with mineral or vegetable oil.
Lubricants also classified by their main functions:-
●    Anti-wear additives:-  Reduces wear by the growth of protective layer on the surfaces.
●    Extreme pressure additives:- Protects the components from seizure by the formation of coating on the surface.
●    Friction modifiers:- Used to control friction typically made of solid particles.
●    Corrosion inhibitors:- Protect the surface from the attack of chemical active substance.

Global Warming:- Scientist interchange the term global warming with climate change. Although temperature rises in certain areas but the ocean current move the heat around in different parts of the globe. As a result of which some regions experience cooler climate and some experience warmer weather. Therefore, climate changes vary in different regions. Hence, the term climate change is generally used by scientists instead of global warming.
 Earth surface has the ability to absorb almost 75% of the entire solar energy. This is responsible for the increase in temperature. However, part of the energy is given back to the atmosphere in the form of radiation. There are certain gases that have the ability to trap heat and restrict the heat from escaping from the atmosphere. These gases are called Greenhouse gases.

Greenhouse effect:- It is a phenomenon by which the radiations comes from the sun is trapped in the Earth’s atmosphere by the greenhouse gases. There greenhouse gases are making layer or blanket around the earth’s surface and trapped by the blanket of greenhouse gases. The main greenhouse gases which cause global warming is Carbon dioxide(CO₂), Ozone(O₃), Chlorofluoro Carbons (CFC), Methane(CH₄), etc.

Plastic is any synthetic or semi-synthetic organic polymer. In other words, while other elements may be present, plastic always includes carbon and hydrogen. While plastic may be made from just about any organic polymer. Most industrial plastic is made from petrochemicals. Thermoplastics and thermosetting polymers are the two types of plastic. The name plastic refers to the property of plasticity, which is the ability to deform without breaking.

Constituent of plastic:- these chains are called polymers. This is why many plastics begin with poly such as Polyethylene, Polystyrene, Polypropylene. Polymer often is made of carbon and hydrogen and sometimes oxygen, nitrogen, sulphur, chlorine, fluorine, phosphorous or silicon.
Application of plastic:- 
1.    Due to its sustainability and durability, it is used in making homes, buildings.
2.    It is used in automobile.
3.    Plastic packaging helps protect and preserve goods.
4.    It is used in safety gears.
5.    It is widely used in electronics like in computer, telephones, mobile phones, etc. due to its light weight.