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32 terms

Topic 3: Thermal Physics

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Thermal energy
a measure of the kinetic and potential energy of the component particles of an object.
Unit: Joule.
Can be transferred by conduction, convention, or radiation
Heat
thermal energy that is absorbed, given up or transferred from one object to another
Temperature
a scalar quantity that gives an indication of the degree of hotness or coldness of a body.
A macroscopic property that measures the average kinetic energy of particles on a defined scale
Thermometric property
property that varies with temperature.
Ex. Expansion of a column of liquid in a capillary tube, electrical resistance of a wire, difference in the rates of expansion of two metals in contact, pressure of a gas at constant volume, volume of a gas at constant pressure, heating of two metal wires wound together, the colour of a solid heated to high temperatures, etc.
Ice point
temperature of pure ice at standard atmospheric pressure
Steam point
temperature of steam at standard atmospheric pressure
Absolute zero
point where molecular vibrations become a minimum - the molecules have minimum kinetic energy but molecular motion does not cease
Internal energy
sum total of the potential energy and the random kinetic energy of the molecules of the substance making up the system
Potential energy
due to energy stored in bonds known as bond energy and intermolecular forces of attraction between particles
Kinetic energy
due to the translational, rotational and vibrational motion of particles
Macroscopic property
one that can be observed.
Ex. Melting point, boiling point, density thermal conductivity, etc.
Brownian motion
zig zag motion of particles caused by the kinetic energy of water molecules
Conduction
the process by which a temperature difference causes the transfer of thermal energy from the hotter region of the body to the colder region by the particles collision without there being any net movement of the substance itself
Convection
the process in which a temperature difference causes the mass movement of fluid particles from areas of high thermal energy to areas of low thermal energy
Radiation
energy produced by a source because of its temperature that travels as electromagnetic waves
Mole
amount of substance that contains as many elementary particles as there are in 0.012 kg of carbon - 12
Avogadro's number
6.02 x 10^23 particles
Molar mass
n = m / M
Thermal capacity
delta Q / delta T.
the capability of substances to store or release different amounts of thermal energy
Specific heat capacity
the heat capacity per unit mass.
The quantity of thermal energy required to raise the temperature of a unit mass of a substance by one degree Kelvin.
Delta Q = m c delta T
Moving particle theory/ Kinetic theory
all matter is composed of extremely particles, all particles are in constant motion, if particles collide with neighboring particles, they conserve their kinetic energy, and a mutual attractive force exists between all particles
Solid
particles are closely packed, each particle strongly bonded to its neighbor, held fairly rigidly in a fixed position, definite shape in a crystalline lattice
Liquid
particles closely packed, bonding between particles quite strong, not held as rigidly in position, bonds can break and reform, potential energy is somewhat higher because more space between particles
Gas
particles widely spaced, only interact significantly upon collision or very close approach, diffusion occurs readily, compressible, much higher potential energy
Evaporation
change from the liquid state to the gaseous state that occurs at temperature below the boiling point
Latent heat
thermal energy which a particle absorbs in melting, evaporating, or sublimating or gives out in freezing, condensing, or sublimating.
Delta Q = m L
Sublimation
direct change of phase directly from a solid to a gas or directly from a gas to a solid
Pressure
P = F / A
Ideal gas
a theoretical gas that obeys the ideal gas law
Boyle's Law
PV = PV
Gay-Lussac Law
V / T = V / T
Pressure Law
P / T = P / T