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CEM 141 chapter 5.pdfCEM 141 chapter
141 chapter
5.pdf####################################################################
5.pdfCEM 141 chapter 5.pdf#############################################
CEM 141 chapter 5
are chemical hand warmers endothermic or exothermic? - ANS-exothermic because the system
(chemicals) is heating up the surroundings (hands)
can we measure heat? - ANS-no, but we can tell which way it is transferred by measuring a
change in the temperature
change in entropy total= - ANS-change in entropy of the system + change in entropy of the
surroundings
closed system - ANS-can transfer energy but not matter
Endothermic - ANS-absorbs heat from the surroundings (+)
Enthalpy - ANS-The heat content of a system at constant pressure
Entropy (S) - ANS-a measure of the number of possible arrangements for a given state
Entropy equation - ANS-S=k log W (where W = the number of arrangements)
Entropy tells which way - ANS-energy transfers occur
exothermic - ANS-Releases heat (-)
first law of thermodynamics - ANS-Energy can be transferred and transformed, but it cannot be
created or destroyed.
for the same substance which phase has the highest entropy? - ANS-gas
gas
translation:
rotation:
vibration: - ANS-"Free, free, free!"
Heat - ANS-strictly defined as the transfer of thermal energy from one place to another (eg by
collisions of molecules)
how can we tell that the KEavg of a substance is increasing - ANS-by measuring the
temperature
-when temperature increases KEavg increases
-when temperature decreases KEavg decreases
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#############################CEM
CEM 141 chapter 5.pdf####################################################################################CE
141 chapter 5.pdfCEM 141 chapter 5.pdf#############################################
,######################################################################################!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Q
#############################CEM
CEM 141 chapter 5.pdfCEM 141 chapter
141 chapter
5.pdf####################################################################
5.pdfCEM 141 chapter 5.pdf#############################################
if enthalpy is negative - ANS-the reaction is exothermic and the surroundings get hotter
If enthalpy is positive - ANS-the reaction is endothermic and the surroundings get colder
Internal Energy (E) - ANS-the sum of the kinetic and potential energies of all particles in the
system
Is sweat evaporating exothermic or endothermic? - ANS-endothermic because energy is being
absorbed to break IMFs
Is water freezing exothermic or endothermic? - ANS-exothermic because energy is being
released
Is wood burning exothermic or endothermic? - ANS-exothermic because heat is being released
isolated system - ANS-cannot transfer matter or energy
KE is normally associated with: - ANS-translation
KE= - ANS-1/2mv^2=3/2kT
liquid
translation:
rotation:
vibration: - ANS-restricted
less free than gas
free
molar heat capacity - ANS-the energy required to raise the temperature of one mole of a
substance by one degree Celsius
more ______ ---> more ______ -----> higher _______ - ANS-motion
KE
temperature
open system - ANS-can transfer energy and matter
path functions - ANS-depend on how change takes place
second law of thermodynamics - ANS-Every energy transfer or transformation increases the
entropy of the universe.
says you can't get back what you put in
######################################################################################!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Q
#############################CEM
CEM 141 chapter 5.pdf####################################################################################CE
141 chapter 5.pdfCEM 141 chapter 5.pdf#############################################
#############################CEM
CEM 141 chapter 5.pdfCEM 141 chapter
141 chapter
5.pdf####################################################################
5.pdfCEM 141 chapter 5.pdf#############################################
CEM 141 chapter 5
are chemical hand warmers endothermic or exothermic? - ANS-exothermic because the system
(chemicals) is heating up the surroundings (hands)
can we measure heat? - ANS-no, but we can tell which way it is transferred by measuring a
change in the temperature
change in entropy total= - ANS-change in entropy of the system + change in entropy of the
surroundings
closed system - ANS-can transfer energy but not matter
Endothermic - ANS-absorbs heat from the surroundings (+)
Enthalpy - ANS-The heat content of a system at constant pressure
Entropy (S) - ANS-a measure of the number of possible arrangements for a given state
Entropy equation - ANS-S=k log W (where W = the number of arrangements)
Entropy tells which way - ANS-energy transfers occur
exothermic - ANS-Releases heat (-)
first law of thermodynamics - ANS-Energy can be transferred and transformed, but it cannot be
created or destroyed.
for the same substance which phase has the highest entropy? - ANS-gas
gas
translation:
rotation:
vibration: - ANS-"Free, free, free!"
Heat - ANS-strictly defined as the transfer of thermal energy from one place to another (eg by
collisions of molecules)
how can we tell that the KEavg of a substance is increasing - ANS-by measuring the
temperature
-when temperature increases KEavg increases
-when temperature decreases KEavg decreases
######################################################################################!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Q
#############################CEM
CEM 141 chapter 5.pdf####################################################################################CE
141 chapter 5.pdfCEM 141 chapter 5.pdf#############################################
,######################################################################################!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Q
#############################CEM
CEM 141 chapter 5.pdfCEM 141 chapter
141 chapter
5.pdf####################################################################
5.pdfCEM 141 chapter 5.pdf#############################################
if enthalpy is negative - ANS-the reaction is exothermic and the surroundings get hotter
If enthalpy is positive - ANS-the reaction is endothermic and the surroundings get colder
Internal Energy (E) - ANS-the sum of the kinetic and potential energies of all particles in the
system
Is sweat evaporating exothermic or endothermic? - ANS-endothermic because energy is being
absorbed to break IMFs
Is water freezing exothermic or endothermic? - ANS-exothermic because energy is being
released
Is wood burning exothermic or endothermic? - ANS-exothermic because heat is being released
isolated system - ANS-cannot transfer matter or energy
KE is normally associated with: - ANS-translation
KE= - ANS-1/2mv^2=3/2kT
liquid
translation:
rotation:
vibration: - ANS-restricted
less free than gas
free
molar heat capacity - ANS-the energy required to raise the temperature of one mole of a
substance by one degree Celsius
more ______ ---> more ______ -----> higher _______ - ANS-motion
KE
temperature
open system - ANS-can transfer energy and matter
path functions - ANS-depend on how change takes place
second law of thermodynamics - ANS-Every energy transfer or transformation increases the
entropy of the universe.
says you can't get back what you put in
######################################################################################!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Q
#############################CEM
CEM 141 chapter 5.pdf####################################################################################CE
141 chapter 5.pdfCEM 141 chapter 5.pdf#############################################
