chem121test3 Flashcards
(66 cards)
energy
the ability to do work or transfer heat
thermodynamics
the study of energy and its transformations
thermochemistry
he study of chemical reactions and the energy changes that involve heat
first law of thermodynamics
Energy can be converted from one form to another, but it is neither created nor destroyed
system
The portion of the universe that we single out to study
surroundings
everything else
Open System
a region of the universe being studied that can exchange heat AND mass with its surroundings
Closed System
a region of the universe being studied that can ONLY exchange
heat with its surroundings
Isolated System
a region of the universe that can NOT exchange heat or mass with its surroundings
internal energy
the sum of all kinetic and potential energies of all components of the system; we use E to represent it
change in internal energy
ΔE = Efinal − Einitial
if ΔE negative
loss of energy
if ΔE positive
gain of energy
heat
q
work
w
change in internal energy type 2
ΔE = q + w
exothermic
releases energy to the environment
endothermic
absorbs energy from the environment
state functions
an absolute variable that doesn’t require comparison
w =
PΔV
enthalpy
the internal energy plus the product of pressure and volume
enthalpy equation
H = E + PV
enthalpy of reaction
The change in enthalpy, ΔH, is the enthalpy of the products minus the enthalpy of the reactants
enthalpy is
an extensive propertythe