I) Choose the member with the higher entropy (S) in each of the following pairs. Materials One with higher S (write a

[answerhappygod]

I) Choose the member with the
higher entropy (S) in each of the following
pairs.
Materials
One with
higher S (write a or b )
i) a. 1 mol
CCl 4 ( l ) or b.
1 mol CH 4 ( g )
ii)
a. 3 mol
O 2 ( g ) or b.
2 mol O 3 ( g )
iii) a. 1 mol
KBr( aq ) or b.
1 mol KBr( s )
Explanation for answer to ii) above is
_____
A.
O 3 has more atoms than
O 2 and hence there are more
microstates.
B. 3 moles of
O 2 molecules have many more microstates than
2 moles of O 3 .
C.
O 3 has a greater molar mass than
O 2 and entropy increases with molar
mass.
D. Motion in
O 2 is less limited and thus its energy is
more dispersed.
II) Classify each of the reactions in
the table with comment as either always
product-favored
( APF ) , never
product-favored
( NPF ) , product favored
only at high temps
( PFHT ) ,
or product-favored only at low temps
( PFLT ) .

a) (Use
the bolded codes.)
Reaction
Δ H°
Δ S°
Comment
(i) N 2 +
3F 2 " 2
NF 3
-249 kJ
-278 J/K
(ii) N 2 +
3Cl 2 " 2
NCl 3
+460 kJ
-275 J/K
(iii)
N 2 F 4 "
2 NF 2
-85 kJ
+198 J/K
b) For any of the above reactions (i) – (iii) that
are favored at high or low temperature, calculate the temperature
at which the transition from being spontaneous to nonspontaneous
and vice-versa occurs.
Transition temperature, T tr =
_____ K
c) Consider the combustion of copper(I) oxide to form
copper(II) oxide.

Cu2O(s)
+ ½
O 2 (g)
---> 2 CuO(s)
; ΔH o =
-146.0 kJ

i) Is this
reaction this
reaction endothermic or exothermic ?
_____

ii)
Given ΔHf o of
Cu2O(s) = -168.6 kJ/mol (and of O2 (g)
= you should know this ),
calculate ΔHf o for CuO(s)
with the proper sign
(+ or -) and the
correct # of
SFs. ΔHf o =
____kJ