Heat and States of Matter Flashcards
explains how particles of matter behave
kinetic theory
all matter is composed of
particles
particles are always in constant random
motion
related to the average kinetic energy of an objects atoms/molecules
temperature
SI unit for temperature
kelvin
define temperature
measure of average kinetic energy of a substances particles
change in thermal energy equation
Q=cmt
what are the four states of matter
solid, liquid, gas, and plasma
what is heat
form of energy that includes both temp and the amount of material
thermal energy?
sum of kinetic and potential energies
heat of fusion
the amount of heat absorbed or release when something melts or freezes
what is thermal expansion
when an object is heated its particles move faster and become less dense causing the object to expand
ways to transfer thermal energy
conduction, convection radiation
conduction?
direct contact
convection
change in temp… flow
radiation
vacuum… transfer of energy by electromagnetic waves (doesn’t require matter)
thermal conductors?
transfers energy easily
thermal insulators?
traps heat/energy
the temp at which the pressure in the liquid of the vapor in the liquid is equal to the external pressure acting on its surface
boiling point
when a gas changes to a liquid
condensation
when a liquid changes to a gas
vaporization
when a liquid changes to a solid
freezing
when a solid changes to a liquid
melting
equation for density
D=m/v
the differences in densities between warmer and cooler fluids cause?
convection currents
how are thermal insulators used to control the transfer of thermal energy
it is the process of trapping heat
first law of thermodynamics
energy is neither created of destroyed. law of conservation of matter
second law of thermodynamics
its impossible for thermal energy to flow from a cool object to a warmer object unless work is done. increased entropy
how does an internal combustion engine convert thermal energy into mechanical energy
gas goes into intake stoke, piston moves down then back up… gas touched spark plug, creating power strike and thermal energy. gas goes back down which opens the exhaust valve and smoke releases. process occurs rapidly
how does the entropy of the universe change when any event occurs
in nature there is no work, so it is increasing
what is entropy
measure of how spread out energy is. it always increases
third law of thermodynamics
“absolute zero”if an object draws energy it can never be at absolute zero. not physically possible
the process when something is heated with out any work being done. the sun is used to heat structures
passive solar
when work is being done to heat/use energy of something. solar panels
active solar
the transfer of thermal energy by convection and conduction both require what
matter
specific heat?
the amount of thermal energy needed to raise the temp of 1kg by 1c of some material
what do the values of specific heat mean
the higher values mean the material requires more thermal energy to raise temp
kinetic energy
form of energy an object has by reason of motion
as particles move farther apart, their potential energy…
increases (stored energy that depends on the distance between particles)
mechanical energy
sum of potential and kinetic energy
heat engine
a device that turns thermal energy into work (not 100% efficient)
heat pump
two way heat mover (like a window AC unit)
what is the heat of vaporization?
amount of energy released when a substance changes from a gas > liquid / liquid > gas
what is heat of fusion?
energy released when a substance changes from liquid > solid or solid > liquid
difference between heat mover and heat pump?
Heat mover only goes one way, heat pump goes two ways (cold to hot or hot to cold)
