Chapter 7: Manufactured Substances in Industry

Overview

Manufactured substances are materials created through chemical processes to enhance human life and meet industrial needs. This chapter explores the chemistry behind various manufactured materials including alloys, glass, ceramics, composite materials, oils and fats, cleaning agents, and pharmaceutical products. Understanding these manufactured substances is essential for appreciating the materials that shape our modern world, from the buildings we live in to the products we use daily. This knowledge also helps us understand the environmental impact and sustainability considerations of industrial production.

Learning Objectives

After studying this chapter, you should be able to:

• Define alloys and explain their importance in industrial applications
• Understand the composition and properties of different types of glass
• Describe ceramic materials and their uses
• Explain composite materials and their advantages
• Analyze oils, fats, and their industrial applications
• Understand the chemistry of cleaning agents (soaps and detergents)
• Explore medicines and cosmetic products
• Consider environmental and sustainability aspects of manufactured substances

7.1 Alloys and Their Importance

What are Alloys?

Alloys are mixtures of two or more elements where the main component is a metal. Alloying modifies the properties of pure metals, making them stronger, harder, and more corrosion-resistant.

Definition and Structure

Alloy definition: A mixture consisting of a major metal component with one or more other elements (metals or non-metals)

Structure: Atoms of different sized elements are inserted into the regular crystal lattice of the pure metal. The presence of these foreign atoms disrupts the orderly arrangement, making it harder for atomic layers to slide past each other.

Properties: Alloys vs Pure Metals

Examples of Alloys and Their Uses

1. Steel (Steel)

Composition: Iron (Fe) + Carbon (C) Properties: Stronger and harder than iron Uses: Building construction, vehicles, machinery

2. Stainless Steel (Stainless Steel)

Composition: Iron (Fe) + Carbon (C) + Chromium (Cr) + Nickel (Ni) Properties: Corrosion resistant Uses: Cutlery, sinks, surgical instruments

3. Bronze (Bronze)

Composition: Copper (Cu) + Tin (Sn) Properties: Hard, strong, corrosion resistant Uses: Medals, monuments, bells

4. Brass (Brass)

Composition: Copper (Cu) + Zinc (Zn) Properties: Strong, lustrous, easily malleable Uses: Keys, musical instruments (trumpets), decorative fittings

5. Duralumin (Duralumin)

Composition: Aluminium (Al) + Copper (Cu) + Magnesium (Mg) + Manganese (Mn) Properties: Lightweight, strong Uses: Aircraft bodies, structural components

6. Pewter (Pewter)

Composition: Tin (Sn) + Antimony (Sb) + Copper (Cu) Properties: Lustrous, corrosion resistant Uses: Decorative items like cups

Key Terms

• Alloying: Process of making alloys
• Corrosion: Gradual deterioration of metals due to chemical reaction with environment
• Crystal lattice: Regular arrangement of atoms in a solid

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Did You Know?

Bronze was so important in human history that the period between 3300-1200 BCE is known as the Bronze Age. Bronze tools and weapons revolutionized agriculture, warfare, and civilization development. The discovery of how to alloy copper with tin was one of the most significant technological advances in human history!

7.2 Composition of Glass and Its Uses

What is Glass?

Glass is an amorphous solid that is transparent, hard, chemically inert, and a good insulator of heat and electricity. The properties of glass can be modified by adding other chemicals during its manufacture.

Main Components

Primary material: Silica or silicon dioxide ($SiO_2$), obtained from sand

Types of Glass

1. Soda-Lime Glass (Soda-lime Glass)

Composition: Silica ($SiO_2$) + Calcium Carbonate ($CaCO_3$) + Sodium Carbonate ($Na_2CO_3$) Properties: Most common type, low melting point, not resistant to sudden temperature changes Uses: Bottles, glass containers, window mirrors

2. Borosilicate Glass (Borosilicate Glass)

Composition: Silica ($SiO_2$) + Boron Oxide ($B_2O_3$) + Sodium Oxide ($Na_2O$) + Aluminium Oxide ($Al_2O_3$) Properties: Low thermal expansion coefficient, resistant to thermal shock Uses: Laboratory apparatus (beakers, conical flasks), cooking containers (Pyrex)

3. Fused Silica Glass (Fused Silica Glass)

Composition: Pure silica ($SiO_2$) Properties: Very high melting point, extremely inert, transparent to UV radiation Uses: Optical lenses, telescopes, high-precision scientific equipment

4. Lead Crystal Glass (Lead Crystal Glass)

Composition: Silica ($SiO_2$) + Lead(II) Oxide ($PbO$) + Potassium Oxide ($K_2O$) Properties: Softer, denser, high refractive index (brilliant) Uses: Decorative crystal items, prisms

Key Terms

• Amorphous: Solid without regular crystalline structure
• Refractive index: Measure of how much light bends when passing through a medium

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SPM Exam Tips

• Remember the main types of glass and their compositions:
  • Soda-lime: Most common, everyday glass
  • Borosilicate: Thermal shock resistance (lab glassware)
  • Fused silica: High purity, UV transparency
  • Lead crystal: High refractive index, decorative
• Know that glass is an amorphous solid (not crystalline)
• Understand how composition affects properties

7.3 Composition of Ceramics and Their Uses

What are Ceramics?

Ceramics are inorganic, non-metallic solids made from clay fired at very high temperatures. They are extremely hard, brittle, heat-resistant, and chemically resistant.

Main Components

Primary material: Clay, especially kaolin or hydrated aluminium silicate ($Al_2O_3 \cdot 2SiO_2 \cdot 2H_2O$)

Properties of Traditional Ceramics

• Hard and strong in compression
• Brittle (breaks without bending)
• Good heat and electrical insulators
• Chemically inert
• Very high melting points

Advanced Ceramics

Advanced ceramics are made from inorganic non-metallic materials like oxides, carbides, and nitrides. Their properties are enhanced for specific applications.

Examples:

• Aluminium oxide ($Al_2O_3$)
• Silicon carbide ($SiC$)
• Silicon nitride ($Si_3N_4$)

Uses

Traditional Ceramics

• Tableware (plates, bowls, cups)
• Tiles, bricks
• Pots
• Electrical insulators

Advanced Ceramics

• Cutting tool blades
• Car brake discs
• Jet engines
• Medical implants (bones and teeth)
• Semiconductor chips

Key Terms

• Ceramic: Inorganic non-metallic solid
• Brittle: Prone to break or crack without bending
• Fired: Process of heating clay at high temperatures

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Safety Reminder

When working with ceramic materials:

• Handle broken ceramics carefully (sharp edges)
• Use proper eye protection when cutting or grinding ceramics
• Be aware of dust generation and use appropriate ventilation
• Follow proper disposal procedures for ceramic waste
• Wear protective gloves when handling unfired clay

7.4 Composite Materials and Their Importance

What are Composite Materials?

Composite materials are new materials created by combining two or more different materials (matrix substance and reinforcing substance) to produce a material with better combined properties than the original components.

Structure

Components:

• Matrix substance: Surrounds and binds the reinforcing material
• Reinforcing substance: Provides strength and rigidity

Purpose: To combine the best properties of the constituent materials

Examples of Composite Materials and Their Uses

1. Reinforced Concrete (Reinforced Concrete)

Matrix: Concrete (cement, sand, aggregate mixture) Reinforcement: Steel mesh or steel bars Properties & Uses: Extremely strong, used in building construction, bridges, and dams

Why it works:

• Concrete is strong in compression but weak in tension
• Steel is strong in tension
• Together they resist both types of stress

2. Fibreglass (Fibreglass)

Matrix: Plastic (polyester resin) Reinforcement: Glass fibers Properties & Uses: Lightweight, strong, corrosion-resistant, non-conductive

• Car bodies, boats, water tanks, helmets

3. Carbon Fiber (Carbon Fiber)

Matrix: Plastic (epoxy resin) Reinforcement: Carbon fibers Properties & Uses: Very lightweight, very strong, rigid

• Racing bicycles, tennis rackets, aircraft components

4. Photochromic Glass (Photochromic Glass)

Matrix: Glass Reinforcement: Silver chloride ($AgCl$) and copper(I) chloride ($CuCl$) crystals Properties & Uses: Becomes dark when exposed to UV light and returns to transparent in dim light

• Sunglass lenses, smart windows

Key Terms

• Composite material: Material consisting of two or more constituent materials with different physical or chemical properties
• Matrix substance: Main material that acts as a binder
• Reinforcing substance: Material that provides strength and rigidity

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Did You Know?

The strongest known material at the nanoscale is graphene, a single layer of carbon atoms arranged in a hexagonal lattice. While not a traditional composite, advanced composite materials incorporating graphene are being developed that could revolutionize aerospace, automotive, and construction industries with unprecedented strength-to-weight ratios!

7.5 Oils and Fats

What are Oils and Fats?

Oils and fats are important esters in diet and industry. The main difference between them is their physical state at room temperature, which is determined by whether they are saturated or unsaturated.

Composition

Triglycerides: Esters of glycerol and three fatty acids

Sources

Fats: Mostly from animal sources (meat, butter) Oils: Mostly from plant sources (palm oil, olive oil, sunflower oil)

Saturated vs Unsaturated Fats

Types of Unsaturated Fats

• Monounsaturated: One $C=C$ bond
• Polyunsaturated: More than one $C=C$ bond

Industrial Uses

Soap making: Oils/fats + concentrated alkali $\rightarrow$ soap + glycerol Margarine production: Vegetable oils + hydrogen $\rightarrow$ solid fat Paints and coatings: Oil-based formulations Biodiesel: Transesterification of vegetable oils

Key Terms

• Cholesterol: Substance important for bodily functions but can cause health problems in excess
• Triglyceride: Ester formed from glycerol and three fatty acids
• Saturated fat: Fat that has no $C=C$ bonds in its fatty acid chains
• Unsaturated fat: Fat that has one or more $C=C$ bonds in its fatty acid chains

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SPM Exam Tips

• Remember that fats are solid at room temperature, oils are liquid
• Know that saturated fats come mainly from animals, unsaturated from plants
• Understand the health implications: saturated increases bad cholesterol, unsaturated increases good cholesterol
• For industrial uses, focus on soap making and margarine production
• Be able to explain the hydrogenation process for oil conversion

7.6 Cleaning Agents

What are Cleaning Agents?

Cleaning agents are substances used with water to remove dirt. Two main types are soaps and detergents.

Soaps

Preparation (Saponification)

Process: Alkaline hydrolysis (heating) of oils or fats with concentrated alkali ($NaOH$ or $KOH$) Reaction: $\text{Fat} + \text{Concentrated Alkali} \rightarrow \text{Soap (Sodium/Potassium Salt of Fatty Acid)} + \text{Glycerol}$

Molecular Structure of Soaps

Components:

1. Hydrophilic head: Ionic part ($-COO^-Na^+$) soluble in water
2. Hydrophobic tail: Long hydrocarbon chain soluble in grease/oil but not in water

Detergents

Preparation

Process: Synthetic cleaning agents produced from petroleum fractions (hydrocarbons) Molecular structure: Also have hydrophilic head and hydrophobic tail Types of head groups: $-SO_3^-Na^+$ (alkyl sulfonate) or $-SO_4^-Na^+$ (alkyl sulfate)

Cleaning Action

Mechanism:

1. Cleaning agents reduce surface tension of water, allowing better wetting
2. Hydrophobic tails dissolve in grease/dirt
3. Hydrophilic heads remain in water
4. Water agitation causes grease to detach from surfaces as small droplets
5. Grease droplets are surrounded by cleaning agent molecules (forming micelles), with negatively charged heads facing outward
6. Repulsion between charges prevents grease droplets from rejoining and keeps them suspended in water (emulsion), allowing removal during rinsing

Comparison of Soap and Detergent Effectiveness

Additives in Detergents

Bleaching Agents

Examples: Sodium perborate Function: Oxidize dirt

Biological Enzymes

Examples: Protease, lipase Function: Break down protein and grease-based dirt

Optical Brighteners

Function: Absorb UV and emit blue light, making clothes appear whiter

Key Terms

• Saponification: Process of making soap
• Hydrophilic: "Water-loving"
• Hydrophobic: "Water-hating"
• Hard water: Water containing high concentrations of calcium and/or magnesium ions
• Scum: Insoluble precipitate formed when soap is used in hard water

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Safety Reminder

When working with cleaning agents:

• Use proper eye protection and gloves
• Ensure good ventilation when using strong cleaning products

• Never mix different cleaning agents (can produce toxic gases)
• Follow manufacturer's instructions for dilution and use
• Store cleaning agents out of reach of children and pets
• Dispose of cleaning chemicals properly according to local regulations

7.7 Medicines and Cosmetics

What are Medicines?

Medicines play a crucial role in treating diseases and improving health. Chemistry is essential in developing medicines for treating diseases and cosmetics for hygiene and beauty.

Traditional vs Modern Medicine

Traditional Medicine

Source: Obtained from natural sources (plants or animals) without complex chemical processing Examples: Ginger (relieves nausea), Aloe vera (treats skin), Ginseng (increases energy)

Modern Medicine

Source: Specific chemicals produced in laboratories to treat or prevent diseases Classification by function:

Analgesics

Function: Relieve pain Examples: Aspirin, Paracetamol, Codeine

Antibiotics

Function: Kill or inhibit growth of bacteria Examples: Penicillin, Streptomycin Note: Not effective against viruses

Psychotropic Drugs

Function: Treat mental illness Examples: Stimulants (stimulate), Antidepressants (reduce depression), Antipsychotics (calm)

Antacids

Function: Weak bases that neutralize excess hydrochloric acid in stomach Examples: Magnesium hydroxide, Aluminium hydroxide

Cosmetics

Definition: Substances or products used to cleanse, protect, or beautify the outer parts of the body

Basic Components

• Water
• Emulsifiers
• Thickeners
• Colorants
• Perfumes
• Preservatives

Key Terms

• Medicine: Substance used to treat or prevent diseases
• Traditional medicine: Medicine from natural sources
• Modern medicine: Specific chemicals produced in laboratories
• Analgesic: Pain-relieving medicine
• Antibiotic: Medicine that kills or inhibits bacteria
• Antacid: Medicine that neutralizes excess stomach acid

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Did You Know?

The pharmaceutical industry develops thousands of new compounds for every one that reaches the market. On average, it takes 12-15 years and costs over $1 billion to bring a new drug from laboratory to market. This rigorous process includes extensive testing for safety and efficacy through multiple phases of clinical trials.

Summary

Key Concepts

1. Alloys are mixtures where main component is metal; they have better properties than pure metals
2. Glass is amorphous solid with main component silica; properties vary with composition
3. Ceramics are inorganic non-metallic solids made from clay fired at high temperatures
4. Composite materials combine two or more materials to get better properties
5. Oils and fats are triglycerides; saturated fats solid, unsaturated fats liquid at room temperature
6. Cleaning agents include soaps and detergents; both have hydrophilic heads and hydrophobic tails
7. Medicines can be traditional (natural) or modern (laboratory-produced)
8. Cosmetics are substances for cleansing, protecting, or beautifying the body

Materials Science

• Structure determines properties in all manufactured materials
• Composition affects behavior and applications
• Environmental considerations include sustainability and disposal
• Industrial applications are diverse and essential to modern life

Practical Applications

• Construction: Steel, concrete, glass
• Transportation: Lightweight alloys, composites
• Healthcare: Medicines, medical implants
• Daily life: Cleaning agents, cosmetics, food products

Environmental Considerations

• Recycling: Important for metals, glass, and some plastics
• Biodegradability: Natural materials vs synthetic materials
• Sustainability: Renewable resources vs non-renewable resources
• Waste management: Proper disposal of manufactured materials

Practice Questions

1. Explain why stainless steel is more corrosion-resistant than plain steel and give examples of its uses.

2. Compare the properties and uses of different types of glass (soda-lime, borosilicate, fused silica, lead crystal).

3. Describe how composite materials like reinforced concrete combine the properties of their components to create superior materials.

4. Explain the difference between soaps and detergents, and why detergents are more effective in hard water.

5. Discuss the importance of medicines in modern healthcare and give examples of different types of medicines with their functions.

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Related Topics:

• Chapter 1: Chemical Equilibrium
• Chapter 2: Rate of Reaction
• Chapter 3: Thermochemistry
• Chapter 4: Electrochemistry
• Chapter 5: Carbon Compounds
• Chapter 6: Oxidation and Reduction