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13
4. Specify the sign of the change in entropy in the following reactionswithout
making a calculation:
C
15
H
31
COOH (s) + 23O
2
(g) = 16CO
2
(g)+ 16H
2
O (g)
2CH
3
OH (g) + 3O
2
(g) = 4H
2
O (g) + 2CO
2
(g)
5. Calculate the ∆S of reaction ATP + H
2
O = ADP + P at 37
0
C. (∆G and ∆H
of the reaction are –30.9 and 20.1 kJ/mol, respectively).
Answer
: 0.16 kJ/mol.
6. Calculate the values
of ∆G of the following iron (II) oxide reduction
reactions:
a) FeO (s) + CO = Fe (s) + CO
2
(g);
∆G
0
(FeO) = –244 kJ/mol; ∆G
0
(CO) = –137 kJ/mol;
b) FeO (s) + C (graphite) = Fe (s) + CO
2
(g)
∆ G
0
(CO
2
) = –394.4 kJ/mol.
What of these reactionsare most likely to occur?
7. What is the value of ∆G, if the equilibrium constant at 298 K
eq
= 1. What is
the value of the equilibrium constant at 298 K
eq
, if ∆G = 0?
8. The condition that causes the equilibrium to shift in the direction of the
reverse reaction (to the left): CO
2
+ C (t)
⇔
2CO – Q:
1) increasing in carbon concentration; 2) cooling; 3) increasing the concen-
tration of carbon monoxide (IV); 4) pressure reduction
9. The equilibrium constant of the reaction of thermal denaturation of chy-
motrypsinogen at pH 2 and 50 °C is 32.7. Calculate the value of the standard
enthalpy of the process if it is known that ∆So = + 1.32 kJ/(mol K). Answer:
417 kJ/mol.
Laboratory work
Experiment 1. Displacement of chemical equilibrium with a change in the
concentration of reagents.
The reaction for the formation of iron (III) thiocyanate is used for the
experiment:
FeCl
3
+ 3KNCS = Fe (NCS)
3
+ 3KCl
Iron (III) thiocyanate is intensively colored red, the solution of FeCl
3
– in
yellowish. KNCS and KCl solutions are colorless.
Pour 20 ml of water in a small measuring beaker, add 1 drop of saturated so-
lutions of FeCl3 and KNCS. Stir the solution with a glass rod. The resulting so-
lution is poured into four tubes. Then add 1 drop of concentrated FeCl3 solution
to the first tube. What are you watching? Record the observed color change in