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Properties of Gases
Dr Claire Vallance First year, Hilary term
Suggested Reading Physical Chemistry, P. W. Atkins Foundations of Physics for Chemists, G. Ritchie and D. Sivia Physical Chemistry, W. J. Moore University Physics, H. Benson
Course synopsis 1. 2. Introduction - phases of matter Characteristics of the gas phase Examples Gases and vapours Measureable properties of gases Pressure Measurement of pressure Temperature Thermal equilibrium and temperature measurements Experimental observations – the gas laws The relationship between pressure and volume The effect of temperature on pressure and volume The effect of the amount of gas Equation of state for an ideal gas Ideal gases and real gases The ideal gas model The compression factor Equations of state for real gases The kinetic theory of gases Collisions with the container walls – determining pressure from molecular speeds The Maxwell Boltzmann distribution revisited Mean speed, most probable speed and rms speed of the particles in a gas Collisions (i) Collisions with the container walls (ii) Collisions with other molecules Mean free path Effusion and gas leaks Molecular beams Transport properties of gases Flux Diffusion Thermal conductivity Viscosity
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1. Introduction - phases of matter There are four major phases of matter: solids, liquids, gases and plasmas. Starting from a solid at a temperature below its melting point, we can move through these phases by increasing the temperature. First, we overcome the bonds or intermolecular forces locking the atoms into the solid structure, and the solid melts. At higher temperatures we overcome virtually all of the intermolecular forces and the liquid vapourises to form a gas (depending on the ambient pressure and on the phase diagram of the substance, it is sometimes possible to go directly from the solid to the gas phase in a process known as sublimation). If we increase the temperature to extremely high...