#practice problem

Integrated Rate Equations - First Order Reactions and Half-life

A second-order reaction has a rate constant of 0.04 L mol⁻¹ s⁻¹ and an initial concentration of 0.2 mol L⁻¹. What is the

t½ = 1/(0.04×0.2) = 125 s.

Ref: NCERT Class 12 Chemistry > Chapter 3: Chemical Kinetics > Topic: Integrated Rate Equations - First Order Reactions and Half-life

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Integrated Rate Equations - First Order Reactions and Half-life

The half-life of a second-order reaction is 25 s when the initial concentration is 0.4 mol L⁻¹. What is the rate constan

k = 1/(25×0.4) = 0.1 L mol⁻¹ s⁻¹.

Ref: NCERT Class 12 Chemistry > Chapter 3: Chemical Kinetics > Topic: Integrated Rate Equations - First Order Reactions and Half-life

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Integrated Rate Equations - First Order Reactions and Half-life

A first-order reaction has a rate constant of 0.0139 min⁻¹. What is the half-life?

t½ = 0.693/0.0139 ≈ 50 min.

Ref: NCERT Class 12 Chemistry > Chapter 3: Chemical Kinetics > Topic: Integrated Rate Equations - First Order Reactions and Half-life

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Integrated Rate Equations - First Order Reactions and Half-life

A second-order reaction has a rate constant of 0.02 L mol⁻¹ min⁻¹ and an initial concentration of 0.4 mol L⁻¹. What is t

t½ = 1/(0.02×0.4) = 125 min.

Ref: NCERT Class 12 Chemistry > Chapter 3: Chemical Kinetics > Topic: Integrated Rate Equations - First Order Reactions and Half-life

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Integrated Rate Equations - First Order Reactions and Half-life

A zero-order reaction has an initial concentration of 0.24 mol L⁻¹ and a rate constant of 3.0 × 10⁻³ mol L⁻¹ s⁻¹. What i

t½ = 0.24/(2×3.0×10⁻³) = 40 s.

Ref: NCERT Class 12 Chemistry > Chapter 3: Chemical Kinetics > Topic: Integrated Rate Equations - First Order Reactions and Half-life

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Integrated Rate Equations - First Order Reactions and Half-life

A second-order reaction has a rate constant of 0.03 L mol⁻¹ min⁻¹ and an initial concentration of 0.15 mol L⁻¹. What is

t½ = 1/(0.03×0.15) ≈ 222.22 min.

Ref: NCERT Class 12 Chemistry > Chapter 3: Chemical Kinetics > Topic: Integrated Rate Equations - First Order Reactions and Half-life

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Dalton's Atomic Theory and Atomic and Molecular Masses

How many grams of MnO₂ are required to produce 1.42 g of Cl₂ with excess HCl? (Molar masses: MnO₂ = 87 g/mol, Cl₂ = 71 g

Reaction: MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂. Moles of Cl₂ = 1.42/71 = 0.02 mol. 1 mol Cl₂ needs 1 mol MnO₂; 0.02 mol needs 0.02 × 87 = 1.74 g.

Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Dalton's Atomic Theory and Atomic and Molecular Masses

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Dalton's Atomic Theory and Atomic and Molecular Masses

What is the mass of water produced when 8 g of CH₄ reacts with 24 g of O₂? (Atomic masses: C = 12, H = 1, O = 16)

Reaction: CH₄ + 2O₂ → CO₂ + 2H₂O. Moles: CH₄ = 0.5 mol, O₂ = 0.75 mol. O₂ limits at 0.375 mol CH₄. 0.375 mol CH₄ produces 0.75 mol H₂O = 13.5 g.

Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Dalton's Atomic Theory and Atomic and Molecular Masses

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Dalton's Atomic Theory and Atomic and Molecular Masses

How many significant figures are present in the result of (0.0567 × 298.15)/0.101?

0.0567 (3 sig figs), 298.15 (5 sig figs), 0.101 (3 sig figs). Result ≈ 167.34; limited to 3 sig figs (167).

Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Dalton's Atomic Theory and Atomic and Molecular Masses

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Dalton's Atomic Theory and Atomic and Molecular Masses

A compound contains 38.71% carbon, 9.68% hydrogen, and 51.61% oxygen by mass. What is its empirical formula? (Atomic mas

For 100 g: C = 38.71 g, H = 9.68 g, O = 51.61 g. Moles: C ≈ 3.23, H ≈ 9.68, O ≈ 3.23. Ratio = 1 : 3 : 1; empirical formula = CH₃O.

Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Dalton's Atomic Theory and Atomic and Molecular Masses

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