Subject • Engineering Chemistry

Engineering Chemistry R23
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Derivation

🔥 Nernst Eq.

Scoring

⚡ Beer-Lambert

Numericals

📘 Bond Order

Reactions

🧠 Free Radical

Mistake

❌ Unit Calc.

⏳

IF YOU HAVE ONLY 3 HOURS:

1

Study Nernst Equation & Solved Problems (Unit 3)

🔥 99% Repeat
2

Learn MO diagrams for O₂ and N₂ (Unit 1)

⚡ Easy 8 Marks
3

Prepare Conducting Polymers (Polyacetylene) (Unit 4)

🧠 Viva Important
4

Revise Beer-Lambert Law & Derivation (Unit 5)

📘 Numerical Based
1

Structure & Bonding Models

🧪 Launch Unit I Interactive Workbench (Schrodinger Eq. / MOT / Bond Order) 🚀
Concept 03
⚡ Easy 8 Marks

Molecular Orbital (MO) Theory Visualization

When atomic orbitals overlap, they form lower-energy bonding molecular orbitals (BMO) and higher-energy antibonding molecular orbitals (ABMO). Toggle the structures below to visualize oxygen, carbon monoxide, and Benzene conjugated systems.

Atomic O

V V

2p⁴

Molecular O₂ Formed

Unpaired e⁻V
Unpaired e⁻V

π* 2py, π* 2pz (Antibonding)

VV

σ 2px (Bonding)

Atomic O

V V

2p⁴

Notice the two unpaired electrons in the degenerate π* antibonding levels. This explains why Oxygen (O₂) is paramagnetic and holds a bond order of 2.0.

🧮 Bond Order Calculator Sandbox

Formula: Bond Order = (Nb - Na) / 2

Calculated Result

2.0

This molecule has a Double Bond.
Example: O₂

Concept 08
🧠 Viva Important

Interactive Viva Cards

Question

Why is O₂ paramagnetic while N₂ is diamagnetic?

Hover to reveal answer →
Answer

O₂ contains two unpaired electrons in its degenerate π* (antibonding) orbitals. N₂ has all molecular orbitals fully paired.

Question

What happens to Bond Order if we add an electron to N₂?

Hover to reveal answer →
Answer

Bond Order decreases. The added electron must enter an antibonding (Na) orbital, which subtracts from the bond strength.

2

Modern Engineering Materials

🧪 Launch Unit II Interactive Workbench (Semiconductors / Superconductors / Nano) 🚀
Smart Map

Memory Map: Semiconductors 

Semiconductors
 ├── Intrinsic (Pure Si / Ge)
 │    └── Conductivity relies solely on thermal excitation.
 ├── Extrinsic (Doped)
      ├── P-Type (Trivalent Impurity)
      │    ├── Dopant: Boron, Gallium
      │    └── Majority Carriers: Holes (+)
      └── N-Type (Pentavalent Impurity)
           ├── Dopant: Phosphorus, Arsenic
           └── Majority Carriers: Electrons (-)

Carbon Nanotubes (CNTs)

Cylindrical molecules consisting of rolled-up sheets of single-layer carbon atoms (graphene). Exhibits extraordinary strength and unique electrical properties.

SWCNT MWCNT Arc Discharge Method
3

Electrochemistry & Applications

🧪 Launch Unit III Interactive Workbench (Nernst / Conductivites / Batteries) 🚀
DERIVATION TRACK
🔥 99% Repeat

Nernst Equation Derivation

The Nernst equation connects the standard cell potential (E°) to the concentration of reactants and products (Q) and temperature, allowing calculation of emf in non-standard states.

Step 1: Gibbs Free Energy Relation

ΔG = ΔG° + RT ln(Q)

Where ΔG is free energy, R is universal gas const., T is temperature, Q is reaction quotient.

Step 2: Substitute Electrical Work

-nFE = -nFE° + RT ln(Q)

Electrical work by cell: ΔG = -nFE (n = moles of electrons, F = Faraday's constant 96485 C/mol).

Step 3: Final Nernst Formula

E = E° - (RT/nF) ln(Q)

At 298K: E = E° - (0.0591/n) log(Q)

⚡ Interactive Electrochemistry Sandbox

Nernst EMF Solver

Calculates cell EMF (E) under non-standard concentrations at 298 K.

Calculated Cell EMF (E) 1.1296 V
Molar Conductance Engine

Calculates cell specific conductivity (κ) and molar conductance (Λ_m) instantly.

Sp. Cond (κ) 0.0250 S/cm
Molar Cond (Λ_m) 500.0 S·cm²/mol
4

Polymer Chemistry

🧪 Launch Unit IV Interactive Workbench (Copolymerization / Elastomers / Plastics) 🚀
Mechanism Mode
🔥 99% Repeat

Free Radical Addition Polymerization

Interactive visualization of bond formation via free radicals. This mechanism is key for synthesizing Polyethylene (PE) and Polyvinyl Chloride (PVC).

Step 1: Initiation
R-O-O-R Peroxide
Heat/UV
-->
2 R-O• Free Radical Initiator

The peroxide bond is weak and cleaves homolytically under heat/light, generating two highly reactive free radical species ready to attack monomers.

Step 2: Propagation
R•
+
CH₂=CH₂ Ethylene Monomer
Attacks π bond
-->
R-CH₂-CH₂• Growing Polymer Chain

The free radical attacks the pi (π) bond of the monomer. The unpaired electron is transferred to the end of the new chain, allowing the process to repeat thousands of times.

Step 3: Termination (Coupling)
R-(CH₂)n•
+
•(CH₂)m-R
Coupling
-->
R-(CH₂)n+m-R Final Dead Polymer

Two growing macroradical chains collide and couple their unpaired electrons, forming a stable covalent bond and terminating the polymerization process.

5

Instrumental Methods & Green Chemistry

🧪 Launch Unit V Interactive Workbench (UV-Vis / IR Spectroscopy / Green Synthesis) 🚀

🧮 Beer-Lambert Law Calculator

Beer-Lambert states that absorbance is directly proportional to concentration and path length: A = εcl.

Formula: A = ε · c · l

Calculated Absorbance

7.50

No units (dimensionless). Extensively asked in numericals.

Theory Mode
🌱 Core Topic

12 Principles of Green Chemistry

Green chemistry focuses on designing chemical processes that minimize or eliminate hazardous substances. Commonly asked as a 8-10 marks essay.

1
Atom Economy

Maximize incorporation of all materials used into final product. Minimize by-products.

2
Less Hazardous Synthesis

Generate substances that have little or no toxicity to human health.

Related Study Material

PYQs Predictor Physics Unit 2 Exam Survival Sheets