Chapter 12
Temperature and Kinetic Theory
By Boundless
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The kinetic theory of gases describes a gas as a large number of small particles (atoms and molecules) in constant, random motion.
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Atomic theory is a scientific theory of the nature of matter which states that matter is composed of discrete units called atoms.
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Celsius, or centigrade, is a scale and unit of measurement for temperature. It is one of the most commonly used temperature units.
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In the Fahrenheit scale, the freezing of water is defined at 32 degrees, while the boiling point of water is defined to be 212 degrees.
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Absolute zero is the coldest possible temperature; formally, it is the temperature at which entropy reaches its minimum value.
The kelvin is a unit of measurement for temperature; the null point of the Kelvin scale is absolute zero, the lowest possible temperature.
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Thermal expansion is the tendency of matter to change in volume in response to a change in temperature.
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Objects expand in all dimensions. That is, their areas and volumes, as well as their lengths, increase with temperature.
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Substances expand or contract when their temperature changes, with expansion or contraction occurring in all directions.
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Objects will expand with increasing temperature, but water is the most important exception to the general rule.
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The ideal gas law is the equation of state of a hypothetical ideal gas (in which there is no molecule to molecule interaction).
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An isothermal process is a change of a system in which the temperature remains constant: ΔT = 0.
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Isobaric processis a thermodynamic process in which the pressure stays constant (at constant pressure, work done by a gas is
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With the ideal gas law we can figure pressure, volume or temperature, and the number of moles of gases under ideal thermodynamic conditions.
The number of molecules in a mole is called Avogadro's number (NA)—defined as 6.02x 1023 mol-1.
Absolute temperature is the most commoly used thermodyanmic temperature unit and is the standard unit of temperature.
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Pressure is explained by kinetic theory as arising from the force exerted by molecules or atoms impacting on the walls of a container.
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A gas of many molecules has a predictable distribution of molecular speeds, known as the Maxwell-Boltzmann distribution.
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Temperature is directly proportional to the average translational kinetic energy of molecules in an ideal gas.
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Internal energy is the total energy contained by a thermodynamic system, and has two major components: kinetic energy and potential energy.
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During a phase transition, certain properties of the medium change, often discontinuously, as a result of some external condition.
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The amount of water vapor in air is a result of evaporation or boiling, until an equilibrium is reached.