kinetics

Examples of kinetics in the following topics:

• Kinetic Molecular Theory and Gas Laws

  • The following are the basic assumptions of the Kinetic Molecular Theory:
  • According to Kinetic Molecular Theory, an increase in temperature will increase the average kinetic energy of the molecules.
  • Increasing the kinetic energy of the particles will increase the pressure of the gas.
  • Reviews kinetic energy and phases of matter, and explains the kinetic-molecular theory of gases.
  • Express the five basic assumptions of the Kinetic Molecular Theory of Gases.

• Kinetics

  • This sort of study is called kinetics, and the goal is to write an equation that correlates the observed results.
  • Chemists refer to the sum n + m as the kinetic order of a reaction.
  • The kinetic expressions found for the reactions shown at the beginning of this section are written in blue in the following equations.
  • All the reactions save 7 display second order kinetics, reaction 7 is first order.
  • On the other hand, the kinetic order of a reaction is an experimentally derived number.

• Distribution of Molecular Speeds and Collision Frequency

  • According to the Kinetic Molecular Theory, all gaseous particles are in constant random motion at temperatures above absolute zero.
  • Depending on the nature of the particles' relative kinetic energies, a collision causes a transfer of kinetic energy as well as a change in direction.
  • Kinetic energy can be distributed only in discrete amounts known as quanta, so we can assume that any one time, each gaseous particle has a certain amount of quanta of kinetic energy.
  • Although higher velocity states are favored statistically, however, lower energy states are more likely to be occupied because of the limited kinetic energy available to a particle; a collision may result in a particle with greater kinetic energy, so it must also result in a particle with less kinetic energy than before.
  • As the temperature increases, the particles acquire more kinetic energy.

• Chemical Kinetics and Chemical Equilibrium

  • Chemical kinetics is the study of how quickly a chemical reaction occurs and what factors affect its rate.
  • The study of these factors and rates is known as chemical kinetics.
  • You can read more about reaction rates and rate laws in the Kinetics unit.
  • Discuss which aspects of a reaction are described by chemical kinetics

• The Kinetic Molecular Theory of Matter

  • The kinetic molecular theory of matter explains how matter can change among the phases of solid, liquid, and gas.
  • The kinetic molecular theory of matter offers a description of the microscopic properties of atoms (or molecules) and their interactions, leading to observable macroscopic properties (such as pressure, volume, temperature).
  • The temperature of a substance is a measure of the average kinetic energy of the particles.
  • The kinetic theory of matter is also illustrated by the process of diffusion.

• Solid Solubility and Temperature

  • As the temperature of a solution is increased, the average kinetic energy of the molecules that make up the solution also increases.
  • This increase in kinetic energy allows the solvent molecules to more effectively break apart the solute molecules that are held together by intermolecular attractions.
  • The average kinetic energy of the solute molecules also increases with temperature, and it destabilizes the solid state.
  • The increased vibration (kinetic energy) of the solute molecules causes them to be less able to hold together, and thus they dissolve more readily.

• Reaction Rates and Kinetics

  • Useful information about reaction mechanisms may be obtained by studying the manner in which the rate of a reaction changes as the concentrations of the reactant and reagents are varied.This field of study is called kinetics.
  • Nevertheless, evidence for their existence may be obtained by other means, including spectroscopic observation or inference from kinetic results.

• Root-Mean-Square Speed

  • According to Kinetic Molecular Theory, gaseous particles are in a state of constant random motion; individual particles move at different speeds, constantly colliding and changing directions.
  • The root-mean-square speed takes into account both molecular weight and temperature, two factors that directly affect the kinetic energy of a material.

• The Photoelectric Effect

  • If excess photon energy is absorbed, some of the energy liberates the electron from the atom and the rest contributes to the electron's kinetic energy as a free particle.
  • However, if just the intensity of the incident radiation is increased, there is no effect on the kinetic energies of the photoelectrons.
  • The maximum kinetic energy of an ejected electron is given by
  • The maximum kinetic energy of an ejected electron is then
  • Kinetic energy must be positive for ejection to take place, so we must have f > f0 for the photoelectric effect to occur.

• Gas Diffusion and Effusion

  • The kinetic theory describes a gas as a large number of submicroscopic particles (atoms or molecules), all of which are in constant rapid motion that has randomness arising from their many collisions with each other and with the walls of the container.
  • Not only do gaseous particles move with high kinetic energy, but their small size enables them to move through small openings as well; this process is known as effusion.
  • Graham's Law can be understood as a consequence of the average molecular kinetic energy of two different gas molecules (marked 1 and 2) being equal at the same temperature.
  • (Recall that a result of the Kinetic Theory of Gases is that the temperature, in degrees Kelvin, is directly proportional to the average kinetic energy of the molecules.)
  • Therefore, equating the kinetic energy of molecules 1 and 2, we obtain: