7.3 Heat Flashcards
Temperature (T)
a scaled measure of the average kinetic energy of the particles of a substance
Heat (Q)
the transfer of energy from one substance to another due to their differences in temperature
heat units
joules or calories (same as energy units)
Endothermic processes
System absorbs heat
ΔQ > 0
Exothermic processes
System releases heat
ΔQ < 0
Calorimetry
the process of measuring transferred heat
q = mcΔT
q = heat absorbed or released in a given process
ΔT the change in temperature (Celsius or kelvin)
m = mass
c = specific heat of the substance
specific heat
the amount of energy required to raise the temperature of one gram of substance by one degree Celsius/Kelvin
specific heat of water
1 cal/gK
heat capacity
mc (mass x specific heat)
the amount of heat to be supplied to an object to change the temperature (of the entire object) by 1 degree celcisu/kelvin
molar heat capacity
definition
the amount of heat required to increase the temperature of 1 mole of a substance by 1 degree Kelvin
this is commonly used for gases
molar heat capacity equation
Q = ncΔt
n = moles
q = mL
q = heat absorbed or released
m = mass
L = latent heat (heat of fusion or evaporation, depending on context)
use to determine heat absorbed/released during a phase change where temp stays the same
heat of fusion (ΔHfus)
latent heat for the solid-liquid boundary
the amount of energy (enthalpy) that must be added to a solid substance to transform 1 gram of that substance into a liquid
heat of vaporization (ΔHvap)
latent heat for the liquid-gas boundary
the amount of energy (enthalpy) that must be added to a liquid substance to transform 1 gram of that substance into a gas
