thermo. chem definitions Flashcards
thermal energy
energy available from a substance as a result of the motion of its molecules.
chemical system
a set of reactants and products under study (chemical equation)
surrounding
matter around the system that is capable of absorbing/releasing energy.
heat
amount of energy transferred between substances
exothermic
releasing thermal energy (out of system)
endothermic
absorbing thermal energy (into the system)
open system
matter and energy can move in and out
isolated system
neither matter or energy can move in or out
closed system
energy can move in/out, but matter can not.
specific heat capacity
quantity of heat required to raise the temperature of a unit mass
physical change
change in the form of a substance (no chemical bonds are broken)
chemical change
change in chemical bonds between atoms (rearrangement of atoms)
nuclear change
change in protons / neutrons (new formation of atoms)
Hess law
steps in order to achieve a given target formula
calorimetry
used to measure amounts of heat transferred to or from a substance.
