First year science students 8 chapter imp questions for chemistry ⚗️🧪

 🧪 Chapter-wise Important Questions (First Year Chemistry)

1. Some Basic Concepts of Chemistry

Define mole. Calculate the number of molecules in 5 moles of CO₂.

Differentiate between empirical and molecular formula.

What is limiting reagent? Explain with an example.

Calculate the molar mass of:

a) Na₂CO₃·10H₂O

b) Ca(OH)₂

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2. Structure of Atom

State and explain Heisenberg’s Uncertainty Principle.

Derive the expression for energy of an electron in hydrogen atom (Bohr's model).

What are quantum numbers? Explain the significance of each.

Write electronic configuration of Fe³⁺ and Cr.

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3. Classification of Elements & Periodicity

Define periodicity. What causes periodicity in properties?

Compare atomic radius and ionization energy across a period and down a group.

Why does IE decrease down a group and increase across a period?

Write the modern periodic law.

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4. Chemical Bonding and Molecular Structure

Explain hybridization with examples: sp, sp², sp³.

What is VSEPR theory? Predict the shape of CH₄, NH₃, H₂O.

Define bond order and calculate for O₂, N₂, and CO.

Explain hydrogen bonding and its types.

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5. States of Matter: Gases and Liquids

Derive Boyle’s Law and Charles’ Law from ideal gas equation.

State and explain Dalton’s Law of partial pressures.

What is van der Waals equation? How does it correct ideal gas behavior?

Differentiate between real gas and ideal gas.

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6. Thermodynamics

State First Law of Thermodynamics and explain ΔU = q + w.

Differentiate between enthalpy and internal energy.

Define Hess’s Law with an example.

What is entropy and Gibbs free energy? When is a reaction spontaneous?

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7. Equilibrium

Define equilibrium constant (Kc, Kp) and write expression for a given reaction.

State Le Chatelier’s Principle. Explain the effect of temperature and pressure.

What is pH? Calculate pH of a 0.001 M HCl solution.

Difference between strong and weak electrolytes.

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8. Redox Reactions

Define oxidation, reduction, oxidizing and reducing agent.

Assign oxidation number in the following: KMnO₄, Cr₂O₇²⁻, Fe₂O₃.

Balance the following redox reaction by ion-electron method:

MnO₄⁻ + Fe²⁺ → Mn²⁺ + Fe³⁺

What is disproportionation reaction? Give an example.

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✅ Bonus Tips:

Focus on numerical-based problems in Stoichiometry, Thermodynamics, and Equilibrium.

Pract

ice structure drawing (Lewis, orbitals).

Know all definitions clearly – they are often asked for 1- or 2-mark questions.

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