Kinetics, Thermodynamics and Equilibrium - Revsworld

4) Will A Reaction Happen On Its Own Once Started? Homework
A) Does entropy increase or decrease in the following phase changes and reactions? Are these favored or
unfavored changes?
Reaction
CO 2 (s) CO 2 (g)
I 2 (g) I 2 (s)
C (s) + O 2 (g) CO 2 (g)
4 Al (s) + 2 O 2 (g) 2 Al 2 O 3 (s)
2 CO (g) + O 2 (g) 2 CO 2 (g)
2 H 2 (g) + O 2 (g) 2 H 2 O (l)
Entropy Increase or
Decrease?
Favored or
Unfavored?
B) Water freezes only at temperatures of 0 o C and below: H 2 O (l) H 2 O (s) + 6.01 kJ
1) Is this an increase or decrease in entropy?_____________________________________
2) Is this change favored or unfavored?__________________________________________
3) When water freezes, is this exothermic or endothermic?__________________________
4) Is this change favored or unfavored?___________________________________________
5) Which explanation correctly describes why water only spontaneously freezes at temperatures BELOW 0 o C?
a) The favored entropy factor is greater than the unfavored enthalpy factor.
b) The favored entropy factor is less than the unfavored enthalpy factor.
c) The unfavored entropy factor is greater than the favored enthalpy factor.
d) The unfavored entropy factor is less than the favored enthalpy factor.
C) You have a NiMH AAA rechargeable battery in your mp3 player. After a while, the battery indicator shows
that the battery is losing its charge (running out of “juice”) and needs to be recharged, which you do by
placing the battery into a recharger and plugging it into the outlet in your room. After a few hours, the charger
shows that the battery is now full, so you take it out and put it back in your mp3 player and rock to the tunes.
a) Is discharging the battery spontaneous or nonspontaneous? Why?
b) Is recharging the battery spontaneous or nonspontaneous? Why?
© 2009, Mark Rosengarten AE 30