exam 2 ch 18 pt 2 Flashcards
entropy increases when
the temperature of a substance increases
change in state is normally accompanied by
an exchange of heat btw system and surroundings
melting and vaporization are
endothermic (sys > 0)
fusion and condensation are
exothermic (sys < 0)
a reversible problem is one where after some change
occurs in the system it must be possible to return to starting point without altering surroundings (phase change)
spontaneous processes are
not reversible
isothermal process
a process under a constant temperature such as a phase change
freezing of ice or condensation of water
increase the entropy of surroundings
an exothermic process
increases the entropy of the surroundings
an endothermic process
decreases the entropy of surroundings
chem/physical process occurring at constant temp and pressure Δ S of surroundings can be determined by
amount of heat transferred in and out of surroundings, and by the temp of the surroundings
(constant temp and pressure processes) magnitude of ΔS of surroundings is
proportional to magnitude of ΔH
process that emits heat into surroundings
increases entropy of the surroundings (exothermic)
A process that absorbs heat from the surroundings
decreases the
entropy of the surroundings (endothermic)
magnitude of increase in entropy of surroundings due to dispersal of energy into surroundings is
temperature dependent (higher the temp the smaller the change in entropy for the amount of energy dispersal into surroundings)
at low temps, the decrease in ΔSsys is
overcome by large increase in ΔS surr
at high temps the decrease in ΔS sys is
not overcome by the increase in ΔS surr
ΔS sys (+) ΔS surr (+) and ΔS univ (+)
spontaneous
ΔS sys (-) ΔS surr (-) and ΔS univ (-)
nonspontaneous
ΔS sys (+) ΔS surr (-) and ΔS univ (?)
spontaneous if ΔS sys has larger magnitude than ΔS surr
ΔS sys (-) ΔS surr (+) and ΔS univ (?)
spontaneous if ΔS surr has a larger magnitude of ΔS sys
