Domanda del libro di testo
(c) Do catalysts affect the overall enthalpy change for a reaction, the activation energy, or both?
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Ch.14 - Chemical Kinetics
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970
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TOC.tableOfContents
- Ch.1 - Introduction: Matter, Energy, and Measurement146
- Ch.2 - Atoms, Molecules, and Ions200
- Ch.3 - Chemical Reactions and Reaction Stoichiometry176
- Ch.4 - Reactions in Aqueous Solution155
- Ch.5 - Thermochemistry126
- Ch.6 - Electronic Structure of Atoms131
- Ch.7 - Periodic Properties of the Elements126
- Ch.8 - Basic Concepts of Chemical Bonding123
- Ch.9 - Molecular Geometry and Bonding Theories143
- Ch.10 - Gases147
- Ch.11 - Liquids and Intermolecular Forces91
- Ch.12 - Solids and Modern Materials122
- Ch.13 - Properties of Solutions126
- Ch.14 - Chemical Kinetics174
- Ch.15 - Chemical Equilibrium101
- Ch.16 - Acid-Base Equilibria139
- Ch.17 - Additional Aspects of Aqueous Equilibria146
- Ch.18 - Chemistry of the Environment72
- Ch.19 - Chemical Thermodynamics129
- Ch.20 - Electrochemistry142
- Ch.21 - Nuclear Chemistry101
- Ch.22 - Chemistry of the Nonmetals68
- Ch.23 - Transition Metals and Coordination Chemistry66
- Ch.24 - The Chemistry of Life: Organic and Biological Chemistry10
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970Non è quello che usi tu?Cambia libro di testo
Capitolo 14, Problema 76a
(a) Most commercial heterogeneous catalysts are extremely finely divided solid materials. Why is particle size important?
Guida verificata passo dopo passo1
Understand the concept of surface area in relation to reaction rates: The rate of a chemical reaction involving a solid material can be increased by increasing the surface area of the solid.
Recognize the role of particle size: Smaller particles have a greater surface area to volume ratio compared to larger particles. This means that more of the solid material is available to interact with reactants.
Apply this to heterogeneous catalysts: In heterogeneous catalysis, the catalyst is in a different phase from the reactants. If the catalyst is a solid, maximizing its surface area allows more active sites to be available for the reactants.
Consider the practical implications: Finely divided catalysts enhance the efficiency of the catalytic process, allowing reactions to proceed faster or at lower temperatures, which can be crucial in industrial applications.
Connect to commercial use: For commercial applications, using finely divided catalysts can lead to cost efficiency and higher productivity due to the increased rate of reaction and better utilization of the catalyst.
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Surface Area to Volume Ratio
The surface area to volume ratio is crucial in catalysis because reactions occur at the surface of the catalyst. Smaller particles have a higher surface area relative to their volume, allowing more active sites for reactants to interact. This increased surface area enhances the catalyst's effectiveness, leading to faster reaction rates.
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Percorso guidato
03:47
Perimeter, Area, Volume
Catalytic Activity
Catalytic activity refers to the ability of a catalyst to increase the rate of a chemical reaction without being consumed in the process. The particle size of a catalyst can influence its activity; smaller particles often exhibit higher activity due to more available active sites and better accessibility for reactants, which can lead to improved reaction efficiency.
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02:02Activity Series Chart
Diffusion Limitations
Diffusion limitations occur when reactants cannot reach the active sites of a catalyst quickly enough, which can hinder reaction rates. In heterogeneous catalysis, smaller particle sizes can reduce these limitations by allowing reactants to penetrate the catalyst more easily, thus facilitating faster reactions and improving overall catalytic performance.
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01:30Limiting Reagent Concept
Pratica correlata
Domanda del libro di testo
(a) What is a catalyst? (b) What is the difference between a homogeneous and a heterogeneous catalyst?
Domanda del libro di testo
The addition of NO accelerates the decomposition of N2O, possibly by the following mechanism: NO1g2 + N2O1g2¡N21g2 + NO21g2 2 NO21g2¡2 NO1g2 + O21g2 (b) Is NO serving as a catalyst or an intermediate in this reaction?
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Domanda del libro di testo
You have studied the gas-phase oxidation of HBr by O2: 4 HBr(g) + O2(g) → 2 H2O(g) + 2 Br2(g)
You find the reaction to be first order with respect to HBr and first order with respect to O2. You propose the following mechanism:
HBr(g) + O2(g) → HOOBr(g)
HOOBr(g) + HBr(g) → 2 HOBr(g)
HOBr(g) + HBr(g) → H2O(g) + Br2(g)
(b) Based on the experimentally determined rate law, which step is rate determining?
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