kinetic molecular theory

Examples of kinetic molecular theory in the following topics:

• Kinetic Molecular Theory and Gas Laws

  • Kinetic Molecular Theory explains the macroscopic properties of gases and can be used to understand and explain the 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.
  • 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.

• 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).
  • An application of the theory is that it helps to explain why matter exists in different phases (solid, liquid, and gas) and how matter can change from one phase to the next.
  • 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.

• 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.

• 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.
  • In theory, this energy can be distributed among the gaseous particles in many ways, and the distribution constantly changes as the particles collide with each other and with their boundaries.
  • Larger molecular weights narrow the velocity distribution because all particles have the same kinetic energy at the same temperature.
  • Explore the role of molecular mass on the rate of diffusion.
  • Identify the relationship between velocity distributions and temperature and molecular weight of a gas.

• The Collision Theory

  • Collision Theory provides a qualitative explanation of chemical reactions and the rates at which they occur.
  • A basic principal of collision theory is that, in order to react, molecules must collide.
  • Therefore, in order to effectively initiate a reaction, the reactants must be moving fast enough (with enough kinetic energy) so that they collide with sufficient force for bonds to break.
  • As we know from the kinetic theory of gases, the kinetic energy of a gas is directly proportional to temperature.
  • Discuss the role of activation energy, collisions, and molecular orientation in collision theory

• 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.
  • 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:
  • The rate of effusion is determined by the number of molecules that diffuse through the hole in a unit of time, and therefore by the average molecular velocity of the gas molecules.

• Molecules

  • For example, the term "molecules" is used in the kinetic theory of gases, referring to any gaseous particle regardless of its composition.
  • Molecular size varies depending on the number of atoms that make up the molecule.
  • The full elemental composition of a molecule can be precisely represented by its molecular formula, which indicates the exact number of atoms that are in the molecule.

• Kinetics

  • One way of investigating the molecularity of a given reaction is to measure changes in the rate at which products are formed or reactants are lost, as reactant concentrations are varied in a systematic fashion.
  • Chemists refer to the sum n + m as the kinetic order of a reaction.
  • All the reactions save 7 display second order kinetics, reaction 7 is first order.
  • It should be recognized and remembered that the molecularity of a reaction is a theoretical term referring to a specific mechanism.
  • On the other hand, the kinetic order of a reaction is an experimentally derived number.

• Substances that Exist as Gases

  • The Kinetic Theory of Matter provides a basic overview:
  • The temperature of a substance is a measure of the average kinetic energy of the particles.
  • Explore the structure of a gas at the molecular level.

• Table of Geometries

  • The VSPER theory detremines molecular geometries (linear, trigonal, trigonal bipyramidal, tetrahedral, and octahedral).
  • Molecular geometries (linear, trigonal, tetrahedral, trigonal bipyramidal, and octahedral) are determined by the VSEPR theory.
  • A table of geometries using the VSEPR theory can facilitate drawing and understanding molecules.
  • The table of molecular geometries can be found in the first figure.
  • The bonded angles in the table are ideal angles from the simple VSEPR theory; the actual angle for the example given is in the following column.