Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Dynamics and Kinetics: Transition-State Theory Exercises

In course

CH-310: Dynamics and kinetics

The course covers the principles of chemical kinetics, including differential rate laws, derivation of exact and approximate integral rate laws for common elementary and composite reactions, fundamentals of collision and transition state theories, and appl ...

Description

This lecture covers exercises related to transition-state theory, including estimating rate constants, barrier heights, bond lengths, and vibrational wave numbers for various reactions. The exercises also involve calculating partition functions for translational, rotational, and vibrational motion, as well as pre-exponential factors for gas-phase reactions.

Instructor

Ulrich Lorenz

Official source

Related concepts (32)

Bond length

In molecular geometry, bond length or bond distance is defined as the average distance between nuclei of two bonded atoms in a molecule. It is a transferable property of a bond between atoms of fixed types, relatively independent of the rest of the molecule. Bond length is related to bond order: when more electrons participate in bond formation the bond is shorter. Bond length is also inversely related to bond strength and the bond dissociation energy: all other factors being equal, a stronger bond will be shorter.

Transition state theory

In chemistry, transition state theory (TST) explains the reaction rates of elementary chemical reactions. The theory assumes a special type of chemical equilibrium (quasi-equilibrium) between reactants and activated transition state complexes. TST is used primarily to understand qualitatively how chemical reactions take place.

Reaction rate constant

In chemical kinetics, a reaction rate constant or reaction rate coefficient (k) is a proportionality constant which quantifies the rate and direction of a chemical reaction by relating it with the concentration of reactants. For a reaction between reactants A and B to form a product C, where A and B are reactants C is a product a, b, and c are stoichiometric coefficients, the reaction rate is often found to have the form: Here k is the reaction rate constant that depends on temperature, and [A] and [B] are the molar concentrations of substances A and B in moles per unit volume of solution, assuming the reaction is taking place throughout the volume of the solution.

Transition state

In chemistry, the transition state of a chemical reaction is a particular configuration along the reaction coordinate. It is defined as the state corresponding to the highest potential energy along this reaction coordinate. It is often marked with the double dagger ‡ symbol. As an example, the transition state shown below occurs during the SN2 reaction of bromoethane with a hydroxide anion: The activated complex of a reaction can refer to either the transition state or to other states along the reaction coordinate between reactants and products, especially those close to the transition state.

Rate equation

In chemistry, the rate law or rate equation for a chemical reaction is a mathematical equation that links the rate of forward reaction with the concentrations or pressures of the reactants and constant parameters (normally rate coefficients and partial reaction orders). For many reactions, the initial rate is given by a power law such as where [\mathrm{A}] and [\mathrm{B}] express the concentration of the species \mathrm{A} and \mathrm{B}, usually in moles per liter (molarity, M).

Related lectures (33)

Vibrational Degrees of Freedom in Ozone Decomposition

Explores the probability of different quanta levels in ozone's vibrational degrees of freedom and the estimation of rate constants in chemical reactions.

Chain Polymerisation: Mechanism and Kinetics

Explores the mechanism and kinetics of chain polymerisation, focusing on inhibitors and competitive inhibition in enzyme reactions.

Collision Kinetics: Theory and Applications

Covers the theory and applications of collision kinetics in understanding molecular interactions.

Rate Constant Analysis: Lindemann-Christiansen Theory

Covers rate constant analysis using different theories and the dissociation process of the water dimer after laser excitation.

Transition-State Theory: Rate Constant Estimation