Exercise Solutions Available
Step-by-step answers for all textbook questions in this chapter
Chapter 1 — Basic Concepts
1-mark: Define mole. What is Avogadro's number? State law of conservation of mass. 3-mark: Calculate empirical formula from: 40% C, 6.67% H, 53.33% O. Distinguish empirical and molecular formula. 5-mark: Explain stoichiometry with a limiting reagent problem. Calculate mass of product when 10 g Fe reacts with excess S.
Chapter 2 — Quantum Model of Atom
1-mark: State Pauli exclusion principle. How many orbitals in n = 4? What is the shape of a p orbital? 3-mark: Why does Cr have [Ar] 3d⁵ 4s¹? Explain Hund's rule with nitrogen. Write values of all quantum numbers for the 4d electron. 5-mark: Explain the three rules for electron filling. Write electronic configurations of Z = 1 to 20.
Chapter 3 — Periodic Classification
1-mark: Which element has the highest electronegativity? State the modern periodic law. Define ionisation energy. 3-mark: Explain why IE of N > O. Describe lanthanide contraction and its consequences. Compare atomic radii of Na, Mg, Al. 5-mark: Describe all periodic trends (atomic radius, IE, EA, EN) across a period and down a group with reasons and exceptions.
Chapter 6 — Gaseous State
1-mark: State Boyle's law. What is the value of R in SI units? Define STP. 3-mark: Derive combined gas law. A gas at 27°C and 2 atm occupies 10 L — find volume at 127°C and 1 atm. State Graham's law. 5-mark: State KMT postulates. Derive u_rms = √(3RT/M). Explain real gas deviation from ideal behaviour.
Chapter 7 — Thermodynamics
1-mark: Define enthalpy of formation. State the first law. What is the sign of ΔS for increased disorder? 3-mark: Explain Hess's law with an example. Derive ΔH = ΔU + ΔngRT. What is the enthalpy of neutralisation? 5-mark: Explain Gibbs energy. Derive ΔG = ΔH − TΔS. Apply to all four sign combinations of ΔH and ΔS.
Chapter 8 — Equilibrium
1-mark: Define dynamic equilibrium. State Le Chatelier's principle. What is Kw? 3-mark: Write Kc and Kp for 2SO₂ + O₂ ⇌ 2SO₃. Derive Kp = Kc(RT)^Δng. Calculate pH of 0.01 M HCl. 5-mark: Explain ionic equilibrium. Discuss the common ion effect with numerical example involving CH₃COOH and CH₃COONa.
Chapter 9 — Solutions
1-mark: Define molality. What is the van't Hoff factor for K₂SO₄? State Raoult's law. 3-mark: 5.85 g NaCl in 500 g water — find ΔTf (Kf = 1.86). Explain osmosis and reverse osmosis. Define isotonic solutions. 5-mark: Describe all four colligative properties with formulae. Explain how van't Hoff factor corrects for dissociation.
Chapter 10 — Chemical Bonding
1-mark: What is the geometry of SF₆? Define bond order. What is the hybridisation in C₂H₂? 3-mark: Explain VSEPR for NH₃. Why is H₂O polar but CO₂ nonpolar? Write the MO configuration of N₂. 5-mark: Explain sp³ hybridisation with methane. Draw the MO diagram of O₂ and justify paramagnetism.
Chapters 11 & 12 — Organic Chemistry
1-mark: Give IUPAC name of CH₃CH₂CHO. Define chiral carbon. What is hyperconjugation? 3-mark: Draw and name all structural isomers of C₄H₁₀. Explain mesomeric effect with +M and −M examples. Define and compare nucleophile and electrophile. 5-mark: Explain IUPAC naming rules with five examples of increasing complexity. Describe carbocation stability with hyperconjugation and inductive effect.