Day 47 – Morning Session: Chemistry – Glass & Ceramics – ECET 2026

In ECET Chemistry, Glass and Ceramics are repeated concepts. They are part of engineering materials and are often tested with direct definition-based and application questions.

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📘 Concept Notes

🔹 Glass

• Definition: Glass is an amorphous, transparent or translucent material formed by cooling a molten mixture of silicates rapidly without crystallization.
• Major constituent: Silica (SiO₂).

Composition of Ordinary Glass:

• Silica – network former
• Soda – flux (lowers melting point)
• Lime – stabilizer (improves durability)

Types of Glass:

1. Soda-lime glass: Used in bottles, windowpanes.
2. Pyrex (Borosilicate) glass: Contains ; resistant to heat/chemicals (used in lab glassware, kitchenware).
3. Lead glass: Contains PbO; high refractive index, used in optical instruments.
4. Safety glass: Laminated, used in automobiles.
5. Tempered glass: Heat-treated, strong, used in mobiles, building panels.

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🔹 Ceramics

• Definition: Ceramics are inorganic, non-metallic crystalline solids made by heating raw materials (like clay) at high temperatures.
• Examples: porcelain, bricks, tiles.

Composition:

• Kaolinite (clay mineral)
• Feldspar
• Quartz

Properties:

• Hard, brittle, resistant to heat, corrosion-resistant.
• Electrically insulating.

Types of Ceramics:

1. Traditional ceramics: Bricks, tiles, earthenware.
2. Advanced ceramics: Alumina , Silicon Carbide , used in electronics, aerospace, medical implants.

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⚙️ Formulas

1. Density formula:

Thermal expansion relation:

For refractive index of glass:

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📐 Example

• A glass rod of length expands by when heated from to .
  Find coefficient of linear expansion .

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🔟 10 Expected MCQs – ECET 2026

Q1. Glass is an example of:
A) Crystalline solid
B) Amorphous solid
C) Metal
D) Polymer

Q2. Ordinary glass is composed mainly of:
A) SiO₂, Na₂O, CaO
B) Al₂O₃, Fe₂O₃, MgO
C) SiC, B₂O₃, PbO
D) NaCl, KCl, CaCl₂

Q3. Pyrex glass is resistant to:
A) Only mechanical stress
B) Only corrosion
C) Heat and chemicals
D) Electrical current

Q4. Lead glass is used in:
A) Bottles
B) Windows
C) Optical instruments
D) Cookware

Q5. The clay mineral kaolinite has formula:
A)
B)
C)
D)

Q6. Advanced ceramics include:
A) Bricks
B) Alumina, Silicon Carbide
C) Tiles
D) Glassware

Q7. The density formula is:
A)
B)
C)
D) None

Q8. The refractive index of glass is given by:
A)
B)
C)
D) None

Q9. Tempered glass is mainly used in:
A) Bricks
B) Automobiles and mobiles
C) Ceramics
D) Optical instruments

Q10. Ceramics are generally:
A) Metals
B) Conductors
C) Hard and brittle
D) Flexible

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✅ Answer Key

Q.No	Answer
Q1	B
Q2	A
Q3	C
Q4	C
Q5	B
Q6	B
Q7	B
Q8	B
Q9	B
Q10	C

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🧠 Explanations

• Q1 → B: Glass is amorphous, not crystalline.
• Q2 → A: Ordinary glass has SiO₂, Na₂O, CaO.
• Q3 → C: Borosilicate (Pyrex) resists both heat and chemicals.
• Q4 → C: Lead glass → high refractive index → optical use.
• Q5 → B: Kaolinite = .
• Q6 → B: Advanced ceramics are high-tech like Alumina, SiC.
• Q7 → B: Density = .
• Q8 → B: .
• Q9 → B: Tempered glass → mobiles, cars, building panels.
• Q10 → C: Ceramics are hard, brittle.

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🎯 Why Practice Matters

• ECET exam often asks direct one-liners from Glass & Ceramics.
• Simple recall-based → scoring section.
• Understanding formulas helps in application questions.

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