Chapter 16 Review Packet
AP Chemistry Chapter 16 Practice Multiple Choice Portion
For which process is ΔS negative?
1.
Note:
S
ΔS = S
if ΔS is positive, S
therefore,
> S
final
initial
final
initial
if ΔS is negative, S
< S
final
initial
a.
evaporation of 1 mole of CCl
(ℓ)
4
so ΔS = +
S
< S
<< S
solid
liquid
gas
b.
mixing 5 mL of ethanol with 25 mL of water
ΔS = + because larger volume and more positional disorder
c.
compressing 1 mole Ne at constant temperature
ΔS = because a decrease in volume is less positions
d.
raising the temperature of 100 g Cu from 275 K to 295 K
T increases so S increases (greater motion) so ΔS = +
e.
grinding a large crystal of KCl to powder
more positions so ΔS = +
In what reaction is ΔS° expected to be positive?
2.
(g) I
a.
I
(s)
2
2
so ΔS =
S
< S
final
initial
O (ℓ) H
b.
H
O (s)
2
2
so ΔS =
S
< S
final
initial
(g) CO
c.
CH
OH (g) + 1.5 O
(g) + 2 H
O (ℓ)
3
2
2
2
1.5 so ΔS =
2.5 gaseous moles
1 gaseous mole; 1
2.5 =
(g) + 2 SO (g) 2 SO
d.
2 O
(g)
2
3
2 so ΔS =
4 gaseous moles
2 gaseous mole; 2
4 =
e.
none of these
3.
Which statement is true?
a.
All real processes are irreversible.
page 809
b.
A thermodynamically reversible process takes place infinitely fast.
c.
In a reversible process, the state functions of the system are always much greater
than those of the surroundings.
d.
There is always more heat given off to the surroundings in a reversible process
than in an unharnessed one.
e.
All statements (a-d) are true.