Define thermoplastics and thermosetting plastics and differentiate them

Thermoplastics 

• They are polymers that can be melted and reshaped multiple times without losing their properties.
• Thermoplastics have a linear or branched structure that allows them to move and flow when heated.
• Thermoplastics can be extruded, molded, or formed using heat and pressure.
• Examples of thermoplastics include polyethylene, polypropylene, and polystyrene.
  

Thermosetting

• They plastics are polymers that cannot be melted and reshaped once they have been cured.
• Thermosetting plastics have a cross-linked structure that prevents them from melting or flowing when heated.
• Thermosetting plastics require heat and pressure to cure and become rigid.
• Examples of thermosetting plastics include epoxy, phenolic, and melamine.
• Thermosetting plastics are more rigid and stable than thermoplastics, making them useful in applications where dimensional stability is important.
• Thermoplastics are more flexible and can be used in applications where impact resistance and flexibility are important.

Describe the disadvantages of plastics

 Describe the disadvantages of plastics:

• Plastics can take hundreds of years to degrade in the environment, leading to pollution and harm to wildlife.
• Plastics can release harmful chemicals, such as bisphenol A (BPA) and phthalates, when they degrade or are heated.
• Plastics can be difficult to recycle and may require specialized equipment and facilities.
• Plastics can contribute to greenhouse gas emissions during production and incineration.
• Plastics can pose a risk to human health if ingested or inhaled, especially if they contain harmful chemicals.
• Plastics can be flammable and may release toxic fumes when burned.
• Plastics can be brittle and may crack or break over time, especially when exposed to sunlight.
• Plastics can be affected by temperature and may warp or deform when exposed to heat or cold.
• Plastics may not be biodegradable and can accumulate in landfills and oceans, creating environmental hazards.
• Plastics can be difficult to dispose of safely, leading to litter and waste.

Describe the advantages of plastics over traditional material

 Describe the advantages of plastics over traditional materials:

• Plastics are lightweight, making them easy to transport and handle.
• Plastics are durable and can resist wear, impact, and chemical damage.
• Plastics are flexible and can be molded into complex shapes, making them versatile and customizable.
• Plastics are inexpensive to produce and can be mass-produced, making them cost-effective for many applications.
• Plastics can be designed to have specific properties, such as resistance to UV radiation or fire.
• Plastics can be recycled and reused, reducing waste and environmental impact.
• Plastics can be made from renewable resources, such as plant-based polymers.
• Plastics can be sterilized, making them suitable for use in medical and food applications.
• Plastics can provide insulation and improve energy efficiency in buildings and vehicles.
• Plastics can be used to create new materials with unique properties and applications.

Describe the types of polymerization - 1.addition and 2.condensation

 

Describe the types of polymerization (addition and condensation):

Addition

• Addition polymerization involves the addition of monomers without the elimination of any small molecules.
• Addition polymerization can be initiated by heat, light, or chemical catalysts.
• Addition polymerization can produce polymers with high molecular weight and high purity.
• Examples of addition polymers include polyethylene, polypropylene, and polyvinyl chloride.

condensation

• Condensation polymerization involves the elimination of small molecules, such as water, during polymerization. Condensation
• polymerization can produce polymers with low molecular weight and high polydispersity.
• Examples of condensation polymers include nylon, polyester, and polyurethane.
• Condensation polymerization can be carried out using di- or polyfunctional monomers.
• Condensation polymerization can be carried out in solution or in the solid state.
• The properties of condensation polymers can be affected by the reaction conditions, such as temperature and pressure.
• The stereochemistry of the monomers can affect the properties of the resulting polymer.
• The structure of the monomers can affect the properties of the resulting polymer.
• The purity of the monomers can affect the properties of the resulting polymer.
• Polymerization can be a complex process that requires careful control of the reaction conditions.
• Polymerization can be used to create a wide range of materials with unique properties.

Define plastic and types of plastics

 

Define plastic and types of plastics:

• Plastic is a synthetic material made from polymers that can be molded into various shapes.
• Plastics have many applications, including in packaging, construction, and transportation.
• Plastics can be made from a variety of polymers, including polyethylene, polystyrene, and polyvinyl chloride.
• Plastics can be classified based on their properties, such as thermoplastics and thermosetting plastics.
• Thermoplastics can be melted and reshaped multiple times without losing their properties.
• Examples of thermoplastics include polyethylene, polypropylene, and polystyrene.
• Thermosetting plastics cannot be melted and reshaped once they have been cured.
• Examples of thermosetting plastics include epoxy, phenolic, and melamine.
• Plastics can also be classified based on their properties, such as amorphous and crystalline plastics.
• Amorphous plastics have a disordered molecular structure and are transparent and brittle.
• Examples of amorphous

Define polymer and polymerization

 Define polymer and polymerization:

Polymer:

• Polymers are large molecules made up of many smaller units called monomers that are joined together.
• Some common examples of polymers include plastics, rubber, and DNA.
• The properties of a polymer, such as its strength and flexibility, depend on the specific monomers used and how they are arranged.
• Polymers can be natural or synthetic, with some occurring in nature and others made in a laboratory or factory.
• Polymers have a wide range of uses, from packaging materials and medical devices to textiles and electronics.

Polymerization:

• Polymerization is a chemical reaction that joins together many small molecules, called monomers, to form a large molecule called a polymer.
• There are two main types of polymerization: addition and condensation.
• In addition polymerization, monomers are joined together without the loss of any byproducts, while in condensation polymerization, small molecules, such as water or alcohol, are formed as byproducts.
• Polymerization can be initiated by heat, light, or a catalyst, depending on the specific reaction.
• Polymerization is used to create a wide range of products, from plastics and adhesives to pharmaceuticals and paints.

ECET: Environmental Chemistry

1. Describe the layers of atmosphere: a.Lithosphere b.Hydrosphere c.Biosphere
2. Define the terms contaminant, pollutant, receptor, sink, particulate
3. Define biotic components
4. Describe forest resources and its uses
5. Define DO,BOD, Threshold limit value,COD
6. Describe concepts deforestration, airpollution, over exploitation
7. Water pollution causes, effects and its control measurements
8. Describe the causes and effects of acid rain green house effect ozone depletion
9. What are renewable and non renewable energy resources
10. Describe ecosystem, producer, consumer and decomposer
11. Describe Biodiversity and threats to Biodiversity

ECET Chemistry: Fuels

1. Define fuel and characteristics of fuel
2. Describe classification of fuel based on physical state and occurance
3. Characteristics of good fuel
4. Define gaseous fuel and its composition and uses a.Water gas b.Producer gas c.Natural gas d.Coal gas e.Bio gas f.Acetylene
5. Describe methane and ethane fuel gas preperation

ECET Chemistry: Polymers

1. Define polymer and polymerization
2. Define plastic and types of plastics
3. Describe the types of polymerization - 1.addition and 2.condensation
4. Describe the advantages of plastics over traditional material
5. Describe the disadvantages of plastics
6. Define thermoplastics and thermosetting plastics and differentiate them
7. Preparation and uses of plastics: 1.Polythene, 2.Pvc, 3.Teflon, 4.Polystyrene, 5.Urea-formaldehyde, 6.Bakelite, 7.Rubber, 8.Natural rubber
8. Processing of rubber from latex
9. Describe the butyl Rubber, Buna-s, Neoprene rubber and its uses
10. Describe the process of vulcanization

What are the advantages and disadvantages of osmosis and reverse osmosis

 Advantages and disadvantages of osmosis and reverse osmosis:

Advantages of Osmosis:

• It is a natural process that occurs without the need for external energy input.
• It is a passive process that requires no electrical or mechanical equipment.
  

Disadvantages of Osmosis:

• It requires a concentration gradient to be effective, which may not always be present.
• It can result in water being drawn away from cells, leading to dehydration or osmotic stress.

Advantages of Reverse Osmosis:

• It can effectively remove a wide range of contaminants, including salts, heavy metals, and organic pollutants.
• It is a low-cost method of producing purified water.

Disadvantages of Reverse Osmosis:

• It requires a significant amount of pressure to force water through the membrane, which can be energy-intensive.
• The process can be slow and may require multiple stages to achieve desired purification levels.
• The waste stream generated during reverse osmosis can be high, leading to potential environmental impacts.

Describe the processes of osmosis and reverse osmosis

 Processes of osmosis and reverse osmosis:

 

Osmosis: 

• Osmosis is the natural movement of water molecules from an area of high concentration to an area of low concentration through a selectively permeable membrane. 
• In osmosis, the water moves from a dilute solution to a more concentrated solution until the concentration of solutes is equal on both sides of the membrane.

Reverse Osmosis (RO):

•  Reverse osmosis is a process that uses pressure to reverse the natural flow of water in osmosis. 
• In reverse osmosis, water is forced through a semipermeable membrane that removes impurities and contaminants, producing a purified water stream.

Describe the municipal treatment of water for drinking purpose

Municipal water treatment is a multi-step process aimed at providing safe and potable drinking water for communities. The following is a general overview of the steps involved in municipal water treatment:

1. Coagulation and Flocculation:

In this step, chemicals are added to the water to neutralize any positive charges and cause particles to come together and form larger particles, or flocs.

2. Sedimentation: 

The flocs formed in the previous step settle to the bottom of the treatment tank, allowing clear water to rise to the top.

3. Filtration:

The clear water is then filtered through sand or other materials to remove any remaining particles and impurities.

4. Disinfection: 

The water is then disinfected to kill any remaining pathogens and microorganisms. This is typically done using chemicals such as chlorine or ozone.

5. pH Adjustment: 

If necessary, the pH of the water may be adjusted to a neutral level.

6. Fluoridation: 

Fluoride may be added to the water to help prevent tooth decay.

7. Storage: 

The treated water is then stored in a reservoir or tank for distribution to homes and businesses.

Define the degree of hardness, and its use and units

 Degree of hardness, its use and units:

 

Definition:

• The degree of hardness refers to the amount of dissolved minerals, such as calcium and magnesium ions, in a given water supply.

Uses:

• The degree of hardness is an important water quality parameter because it affects the properties of water, such as taste, lathering ability, and the ability to form suds.

Units: 

• The degree of hardness is typically measured in milligrams per liter (mg/L) or parts per million (ppm). 
• Different regions may use different units for measuring hardness, but mg/L and ppm are the most commonly used.

Describe the characteristics of drinking water

 Characteristics of drinking water:

• Potability: The most important characteristic of drinking water is that it should be safe to drink and free of harmful contaminants.
• Taste: Drinking water should have a neutral, clean taste and should not have any noticeable odor or flavor.
• Appearance: Drinking water should be clear and free of suspended particles or discoloration.
• PH: The pH of drinking water should be between 6.5 and 8.5, with a pH of 7 considered neutral.
• Dissolved solids: The level of dissolved solids in drinking water should be relatively low, as high levels of dissolved solids can affect the taste and appearance of water.
• Microbial quality: Drinking water should be free of harmful bacteria, viruses, and other pathogens that can cause illness.

What are the disadvantages of hard water in industries

 Disadvantages of hard water in industries:

• Scaling in equipment: One of the main disadvantages of hard water in industries is the buildup of scale in pipes, boilers, and other equipment, which can reduce their efficiency and lead to potential damage.
• Inefficient cleaning: Hard water can also make it difficult to produce a good lather with soaps and detergents, leading to inefficient cleaning and higher usage of these products.
• Clogging of pipes: Over time, hard water can cause clogging of pipes, reducing the flow of water and potentially leading to leaks and other problems.
• Reduced heat transfer: In boilers and other heating equipment, hard water can reduce the efficiency of heat transfer and increase energy consumption.

Describe different types of hardness

There are two main types of hardness in water: temporary hardness and permanent hardness.

Temporary hardness:

• Temporary hardness is caused by the presence of bicarbonate ions (HCO3-) in water, which can dissolve into calcium (Ca2+) and magnesium (Mg2+) ions and carbonate (CO32-) ions. 
• This type of hardness can be removed through boiling, as the bicarbonates will precipitate out of solution and form solid particles that can be filtered out.

Permanent hardness: 

• Permanent hardness, on the other hand, is caused by the presence of dissolved calcium and magnesium ions in water that cannot be removed through boiling. 
• Permanent hardness is usually due to the presence of minerals such as calcium sulfate (CaSO4), magnesium sulfate (MgSO4), and calcium chloride (CaCl2). 
• Permanent hardness can only be removed through physical or chemical treatment methods, such as ion exchange or reverse osmosis.

Define hardness and causes of hardness

• Hardness of water refers to the concentration of dissolved minerals, mainly calcium and magnesium ions, in a given water supply. 
• Hardness is an important water quality parameter because it affects a water's physical and chemical properties, such as taste, lathering ability, and the ability to form suds.

Causes of hardness

• Natural sources: The main cause of hardness in water is the presence of dissolved minerals, mainly calcium and magnesium ions, from natural sources such as rocks, soil, and groundwater.
• Geographical location: The hardness of water can vary depending on geographical location and source of water supply, with water in areas with hard rock formations, such as limestone and dolomite, typically having higher levels of hardness.
• Groundwater: Groundwater is often higher in hardness compared to surface water sources, such as rivers and lakes, due to the minerals it picks up as it percolates through soil and rock.
• Industrial processes: Some industrial processes, such as mining and drilling, can also contribute to the hardness of water.
• Use of hard water in boilers: The use of hard water in boilers for heating or power generation can lead to scaling and other issues, and can contribute to the overall hardness of the water supply. 

 

Define soft water and hard water

Soft water and hard water are terms used to describe the mineral content of drinking water.

Soft water: 

• Soft water is water that has low mineral content, and is relatively free of calcium and magnesium ions. 
• It is often referred to as "soft" because it is gentle on pipes and appliances, and does not leave mineral deposits. 
• Soft water is often preferred for use in households and industries as it does not cause scaling in pipes or appliances and is generally better for the environment.

Hard water: 

• Hard water, on the other hand, is water that has a high mineral content, usually including high levels of calcium and magnesium ions. 
• Hard water is often referred to as "hard" because it can cause scaling in pipes and appliances, leading to reduced efficiency and potential damage. 
• Hard water can also affect the taste of drinks and food prepared with it, and can make it difficult to lather soap or shampoo.

Methods of preventing corrosion- a.protective coating, cathodic protection

 Methods of Preventing Corrosion:

 

A. Protective Coatings:

• Protective coatings act as a barrier between the metal and the environment, preventing moisture and air from reaching the metal surface.
• Coatings can be in the form of paint, epoxy, or plastic, and the type used depends on the metal and environmental conditions.
• Protective coatings can be applied using various methods, such as spraying, brushing, or dipping.
• Some coatings can also provide additional benefits, such as heat resistance or UV protection.
• Regular maintenance is important to ensure that the coating remains intact and effective in preventing corrosion.
• Coatings can be applied to both new and old metal surfaces to prevent corrosion.
• Protective coatings are a cost-effective way to prevent corrosion compared to other methods, such as replacing the metal entirely.
• Protective coatings can also enhance the appearance of metal surfaces, making them look more attractive.
• Protective coatings can be used in a variety of settings, such as on vehicles, boats, and buildings.
• Proper application of the coating is essential to ensure its effectiveness in preventing corrosion.

B. Cathodic Protection:

• Cathodic protection involves the use of a sacrificial anode to prevent corrosion.
• A sacrificial anode is a metal that is more reactive than the metal being protected, so it corrodes instead of the protected metal.
• The anode is connected to the metal being protected and a power source, which forces the corrosion to occur on the anode instead of the protected metal.
• Cathodic protection can be applied to both buried and submerged metal structures, such as pipelines or ships.
• The effectiveness of cathodic protection depends on factors such as the type of metal being protected, the size and shape of the structure, and the environment it is in.
• The anode needs to be periodically replaced to ensure the protection remains effective.
• Cathodic protection is often used in combination with other methods, such as protective coatings, to provide added protection against corrosion.
• Cathodic protection can be cost-effective in the long run, as it can extend the life of the protected metal structure and reduce the need for maintenance or replacement.
• Proper installation and monitoring of cathodic protection systems are essential to ensure their effectiveness in preventing corrosion.
• Cathodic protection is a proven method for preventing corrosion and is widely used in a variety of industries, such as oil and gas, marine, and transportation.

Define rusting of iron and its mechanism

 Rusting of Iron:

Definition: 

• The process of corrosion that occurs when iron reacts with water and air to form iron oxide, also known as rust.

 Mechanism of rusting: 

• Rusting is a natural process that happens when iron or steel is exposed to air and water.
• The process of rusting is also known as corrosion.
• Rust is formed when iron reacts with oxygen in the air, which forms iron oxide or rust.
• The presence of water is essential for rusting to occur, as it helps to speed up the reaction between iron and oxygen.
• Rusting can happen faster in areas with high humidity, salty water, or acidic conditions.
• Rusting weakens the metal by causing it to flake and peel away, which can lead to structural damage.
• Rust can also discolor surfaces, making them look unsightly.
• Rust can be prevented by using rust-resistant coatings or by keeping the metal dry.
• Regular cleaning and maintenance can also help prevent rust from forming.
• Rust removal can be done by using a wire brush or sandpaper to scrub away the rust, or by using rust removers that contain chemicals to dissolve the rust.