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

 🔬 Important Chemistry Questions – First Year (8 Chapters)

Chapter 1: Some Basic Concepts of Chemistry

1. Define mole and explain its significance.

2. What is molar mass? How is it calculated?

3. Derive and solve a numerical based on the law of conservation of mass.

4. Define empirical and molecular formula with examples.

5. Solve: Calculate the number of molecules in 5 grams of water.

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Chapter 2: Structure of Atom

1. State the main postulates of Bohr’s atomic model.

2. Derive the energy of an electron in hydrogen atom.

3. What are quantum numbers? Explain their significance.

4. Differentiate between orbit and orbital.

5. Solve: Calculate the wavelength of a photon emitted when an electron jumps from n = 3 to n = 2 in hydrogen.

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Chapter 3: Classification of Elements and Periodicity in Properties

1. Explain Mendeleev’s periodic law.

2. Define and give trends of ionization energy, atomic radius, and electronegativity.

3. How does atomic size vary across a period and down a group?

4. What are s, p, d, and f blocks in the periodic table?

5. Why are noble gases placed in Group 18?

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Chapter 4: Chemical Bonding and Molecular Structure

1. Explain ionic and covalent bonding with examples.

2. What is VSEPR theory? State the shape of H₂O and NH₃ molecules.

3. What is hybridization? Explain sp³ and sp² hybridization.

4. Discuss bond enthalpy, bond length, and bond angle.

5. Differentiate between sigma and pi bonds.

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Chapter 5: States of Matter – Gases and Liquids

1. Derive the ideal gas equation: PV = nRT.

2. State and explain Boyle’s Law and Charles’s Law.

3. What are real and ideal gases?

4. Define van der Waals equation.

5. Solve numerical: Calculate pressure exerted by 2 moles of gas in 5L at 300 K.

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Chapter 6: Thermodynamics

1. Define system, surroundings, internal energy, and enthalpy.

2. State the First Law of Thermodynamics.

3. Explain endothermic and exothermic reactions with examples.

4. What is Hess’s Law? Give an example.

5. Solve: Calculate ΔH using bond enthalpies.

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Chapter 7: Equilibrium

1. Define chemical equilibrium and write the law of mass action.

2. Explain Le Chatelier’s Principle with examples.

3. What is the difference between Kc and Kp?

4. Write the expression for ionic product of water.

5. Solve: Calculate the pH of a solution with [H⁺] = 1×10⁻⁴ M.

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Chapter 8: Redox Reactions

1. Define oxidation, reduction, oxidizing agent, reducing agent.

2. What is oxidation number? How is it calculated?

3. Balance redox reactions using the ion-electron method.

4. Give examples of disproportionation reactions.

5. Dif

ferentiate between redox and non-redox reactions.

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✅ Tips:

Focus on conceptual clarity.

Practice numericals regularly.

Use NCERT examples and exercises.

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