Search

Text Color

Margin Size

Font Type

Enable Dyslexic Font

18: Kinetics

Last updated

Mar 21, 2025
Save as PDF
- 17.17: Calculating Heat of Reaction from Heat of Formation
- 18.1: Chemical Reaction Rate

$\newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} }$

$\newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}}$

$\newcommand{\id}{\mathrm{id}}$ $\newcommand{\Span}{\mathrm{span}}$

( \newcommand{\kernel}{\mathrm{null}\,}\) $\newcommand{\range}{\mathrm{range}\,}$

$\newcommand{\RealPart}{\mathrm{Re}}$ $\newcommand{\ImaginaryPart}{\mathrm{Im}}$

$\newcommand{\Argument}{\mathrm{Arg}}$ $\newcommand{\norm}[1]{\| #1 \|}$

$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$

$\newcommand{\Span}{\mathrm{span}}$

$\newcommand{\id}{\mathrm{id}}$

$\newcommand{\Span}{\mathrm{span}}$

$\newcommand{\kernel}{\mathrm{null}\,}$

$\newcommand{\range}{\mathrm{range}\,}$

$\newcommand{\RealPart}{\mathrm{Re}}$

$\newcommand{\ImaginaryPart}{\mathrm{Im}}$

$\newcommand{\Argument}{\mathrm{Arg}}$

$\newcommand{\norm}[1]{\| #1 \|}$

$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$

$\newcommand{\Span}{\mathrm{span}}$ $\newcommand{\AA}{\unicode[.8,0]{x212B}}$

$\newcommand{\vectorA}[1]{\vec{#1}} % arrow$

$\newcommand{\vectorAt}[1]{\vec{\text{#1}}} % arrow$

$\newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} }$

$\newcommand{\vectorC}[1]{\textbf{#1}}$

$\newcommand{\vectorD}[1]{\overrightarrow{#1}}$

$\newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}}$

$\newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}}$

$\newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} }$

$\newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}}$

$\newcommand{\avec}{\mathbf a}$

$\newcommand{\bvec}{\mathbf b}$

$\newcommand{\cvec}{\mathbf c}$

$\newcommand{\dvec}{\mathbf d}$

$\newcommand{\dtil}{\widetilde{\mathbf d}}$

$\newcommand{\evec}{\mathbf e}$

$\newcommand{\fvec}{\mathbf f}$

$\newcommand{\nvec}{\mathbf n}$

$\newcommand{\pvec}{\mathbf p}$

$\newcommand{\qvec}{\mathbf q}$

$\newcommand{\svec}{\mathbf s}$

$\newcommand{\tvec}{\mathbf t}$

$\newcommand{\uvec}{\mathbf u}$

$\newcommand{\vvec}{\mathbf v}$

$\newcommand{\wvec}{\mathbf w}$

$\newcommand{\xvec}{\mathbf x}$

$\newcommand{\yvec}{\mathbf y}$

$\newcommand{\zvec}{\mathbf z}$

$\newcommand{\rvec}{\mathbf r}$

$\newcommand{\mvec}{\mathbf m}$

$\newcommand{\zerovec}{\mathbf 0}$

$\newcommand{\onevec}{\mathbf 1}$

$\newcommand{\real}{\mathbb R}$

$\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}$

$\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}$

$\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}$

$\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}$

$\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}$

$\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}$

$\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}$

$\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}$

$\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}$

$\newcommand{\laspan}[1]{\text{Span}\{#1\}}$

$\newcommand{\bcal}{\cal B}$

$\newcommand{\ccal}{\cal C}$

$\newcommand{\scal}{\cal S}$

$\newcommand{\wcal}{\cal W}$

$\newcommand{\ecal}{\cal E}$

$\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}$

$\newcommand{\gray}[1]{\color{gray}{#1}}$

$\newcommand{\lgray}[1]{\color{lightgray}{#1}}$

$\newcommand{\rank}{\operatorname{rank}}$

$\newcommand{\row}{\text{Row}}$

$\newcommand{\col}{\text{Col}}$

$\renewcommand{\row}{\text{Row}}$

$\newcommand{\nul}{\text{Nul}}$

$\newcommand{\var}{\text{Var}}$

$\newcommand{\corr}{\text{corr}}$

$\newcommand{\len}[1]{\left|#1\right|}$

$\newcommand{\bbar}{\overline{\bvec}}$

$\newcommand{\bhat}{\widehat{\bvec}}$

$\newcommand{\bperp}{\bvec^\perp}$

$\newcommand{\xhat}{\widehat{\xvec}}$

$\newcommand{\vhat}{\widehat{\vvec}}$

$\newcommand{\uhat}{\widehat{\uvec}}$

$\newcommand{\what}{\widehat{\wvec}}$

$\newcommand{\Sighat}{\widehat{\Sigma}}$

$\newcommand{\lt}{<}$

$\newcommand{\gt}{>}$

$\newcommand{\amp}{&}$

$\definecolor{fillinmathshade}{gray}{0.9}$

Topic hierarchy

18.1: Chemical Reaction Rate
This page compares drag racing to chemical reactions, emphasizing that both involve speed and timing. Drag racing measures elapsed time over a quarter-mile, while chemical reactions have varying rates, from instant to millions of years. Chemists measure these rates in molarity per second (M/s). An example demonstrates calculating average reaction rates, which indicate concentration changes over time.
18.2: Collision Theory
This page discusses the financial implications of car damage, highlighting the costs of repairs, particularly in the absence of insurance. It also explains collision theory, which states that for products to form during reactions, particles must collide with adequate kinetic energy and proper orientation; only effective collisions can rearrange atoms and produce new substances, while ineffective collisions do not result in any changes.
18.3: Activation Energy
This page discusses the risks associated with fireworks during special events, emphasizing the importance of handling them safely. It explains that different chemicals require varying activation energies to initiate reactions, with examples of sodium and calcium demonstrating differing reaction rates with water. The concept of activation energy is defined as the minimum energy needed for reactions to occur, noting that reactions may happen at room temperature or require heating for activation.
18.4: Potential Energy Diagrams
This page explores the myth of Sisyphus, symbolizing endless struggle, and connects it to potential energy diagrams that depict energy changes in chemical reactions. It distinguishes between endothermic and exothermic reactions while discussing enthalpy changes. Additionally, it explains activation energy as a barrier for reactants, influencing the speed of reactions.
18.5: Activated Complex
This page discusses two distinct topics: Velcro, a synthetic material used in activities like "Velcro-jumping," where participants stick to a Velcro wall, and the concept of an activated complex in chemistry, which describes a transient atomic arrangement at the peak of activation energy during reactions. This complex lasts approximately $10^{-13} \: \text{s}$ and can revert to reactants or evolve into products, though its exact structure is largely undetermined.
18.6: Factors Affecting Reaction Rate
This page discusses the stress of driving on crowded freeways and the factors affecting chemical reaction rates. High traffic contributes to driving stress, while in chemistry, factors like concentration, pressure, surface area, and temperature are crucial for reaction speeds. Increased concentration and pressure enhance collision frequency, smaller particles improve surface area, and higher temperatures accelerate particle movement, all contributing to faster reactions.
18.7: Catalysts
This page discusses the harmful emissions from gasoline-powered vehicles, particularly nitrogen oxides and carbon monoxide, and how catalytic converters reduce these pollutants. It explains the role of catalysts in chemistry, highlighting their function in lowering activation energy without being consumed.
18.8: Rate Law and Specific Rate Constant
This page discusses the importance of understanding migration patterns and population changes for infrastructure planning, highlighting the need for timely responses to growth. It also explains how the rate of a chemical reaction, particularly the transformation of reactant $\ce{A}$ to product $\ce{B}$, is affected by reactant concentrations.
18.9: Order of Reaction
This page discusses the impact of forest fires on ecosystems, emphasizing the relationship between fire severity and dry plant material. It also explains chemical kinetics, focusing on first-order reactions, which depend on the concentration of one reactant, and second-order reactions involving multiple reactants. The importance of conducting experiments to establish rate laws and reaction orders is highlighted.
18.10: Determining the Rate Law from Experimental Data
This page discusses the importance of accurate time measurement in studying chemical reaction rates and determining rate laws through experiments with different reactant concentrations. Analyzing a reaction between nitrogen monoxide and hydrogen reveals it is second-order with respect to $\ce{NO}$ and first-order with respect to $\ce{H2}$, resulting in a third-order rate law.
18.11: Reaction Mechanisms and the Elementary Step
This page highlights the complexity behind seemingly straightforward outcomes in both airplane assembly and chemical reactions. It emphasizes that just as an airplane is the product of an intricate assembly line, chemical reactions progress through multiple elementary steps, which are not apparent in the overall balanced equation.
18.12: Reaction Intermediate
This page discusses ozone depletion, a significant environmental issue caused by natural processes and human-made chemicals that protect against UV rays. It explains the two-step reaction involving ultraviolet light and free radicals, detailing how reactants convert to products, exemplified by nitrogen monoxide reacting with oxygen to produce nitrogen dioxide.
18.13: Molecularity
This page discusses jigsaw puzzles as a popular hobby with various difficulty levels and piece shapes, emphasizing their assembly one piece at a time. It also explains molecularity in chemistry, which categorizes reactions into unimolecular, bimolecular, and termolecular based on the number of molecules involved. Examples include a bimolecular reaction between NO and O2 and a reaction converting ozone to oxygen that includes both unimolecular and bimolecular steps.
18.14: Rate-Determining Step
This page discusses the frustrations of airline travel caused by lengthy processes like check-in and security. It compares the inefficiencies of these processes to a chemical reaction's rate-determining step, illustrating with the example of hydrogen peroxide decomposition catalyzed by iodide to emphasize how catalysts can enhance efficiency without being consumed.
18.15: Mechanisms and Potential Energy Diagrams
This page compares roller coasters to chemical reactions, focusing on rate-limiting steps and potential energy diagrams. The ascent of a roller coaster symbolizes the activation energy required for a reaction's initial step. It illustrates a two-step reaction with different activation energies, identifying the first step as the rate-limiting one due to its higher activation energy. The overall enthalpy change is defined by the initial and final states, independent of individual steps.

Support Center

How can we help?