AP Chemistry Thermodynamics WS 0809 - AP Chemistry...

AP Chemistry: Thermodynamics
AP Chemistry Thermodynamics WS 0809.doc
Name: ___________________________________ Date: _______________________ Per: _____
1. The following equation represents the essential change that takes place during the fermentation of
glucose to ethanol:
C
6
H
12
O
6(s)
→ 2C
2
H
5
OH
(l)
+ 2CO
2(g)
Is Δ S
o
positive or negative? Explain.
2. Calculate the change of entropy, Δ S
o
, at 25.0
o
C for the reaction in which urea is formed from NH
3
and
CO
2
.
2NH
3(g)
+ CO
2(g)
→ NH
2
CONH
2(aq)
+ H
2
O
(l)
The standard entropy of urea is 174 J/molK. See the text appendices for additional values.
3. Using values of Δ H
o
f
and S
o
, calculate the standard free energy change, Δ G
o
, for the following
reaction at 25.0
o
C.
N
2(g)
+ 3H
2(g)
→ 2NH
3(g)
4. Using standard free energies of formation, calculate Δ G
o
for the combustion of 1 mol of ethanol,
C
2
H
5
OH, at 25.0
o
C.
C
2
H
5
OH
(l)
+ 3O
2(g)
→ 2CO
2(g)
+ 3H
2
O
(g)
5. Calculate Δ H
o
and Δ G
o
for the reaction
KClO
3(s)
→ 2KCl
(s)
+ 3O
2(g)
Interpret the signs obtained for Δ H
o
and Δ G
o
. Values of Δ H
o
f
(in kJ/mol) are as following: KClO