234 Step 4. Review the Knowledge You Need to Score High
25.C 2 H 4 (g) +3 O 2 (g) 2 CO 2 (g) +2 H 2 O(g)
An equal number of moles of each of the reac-
tants are sealed in a container and allowed to
come to the equilibrium shown above. At equi-
librium which of the following must be true?
I. [CO 2 ] must equal [H 2 O]
II. [O 2 ] must be less than [C 2 H 4 ]
III. [CO 2 ] must be greater than [C 2 H 4 ](A) II and III
(B) I only
(C) III only
(D) II only
(E) I and II26.CH 4 (g) +CO 2 (g) 2 CO(g) +2 H 2 (g)
A 1.00-L flask is filled with 0.30 mol of CH 4 and
0.40 mol of CO 2 , and allowed to come to equi-
librium. At equilibrium, there are 0.20 mol of
CO in the flask. What is the value of Kc, the equi-
librium constant, for the reaction?
(A) 1.2
(B) 0.027
(C) 0.30
(D) 0.060
(E) 3.027.NO 2 (g) 2NO(g) +O 2 (g)
The above materials were sealed in a flask and
allowed to come to equilibrium at a certain tem-
perature. A small quantity of O 2 (g) was added to
the flask, and the mixture allowed to return to
equilibrium at the same temperature. Which of
the following has increased over its original equi-
librium value?
(A) the quantity of NO 2 (g) present
(B) the quantity of NO(g) present
(C) the equilibrium constant, K
(D) the rate of the reaction
(E) the partial pressure of NO(g)28.2CH 4 (g) +O 2 (g) 2CO(g) +4H 2 (g) ΔH < 0In order to increase the value of the equilibrium
constant, K, which of the following changes must
be made to the above equilibrium?
(A) increase the temperature
(B) increase the volume
(C) decrease the temperature
(D) add CO(g)
(E) add a catalyst29.HC 3 H 5 O 2 (aq) +HCOO−(aq) HCOOH(aq)
+C 3 H 5 O 2 −(aq)The equilibrium constant, K, for the above equi-
librium is 7.2 × 10 −^2. This value implies which of
the following?
(A) A solution with equimolar amounts of
HC 3 H 5 O 2 (aq) and HCOO−(aq) is neutral.
(B) C 3 H 5 O 2 −(aq) is a stronger base than HCOO−
(aq).
(C) HC 3 H 5 O 2 (aq) is a stronger acid than
HCOOH(aq).
(D) HCOO−(aq) is a stronger base than C 3 H 5 O 2 −
(aq).
(E) The value of the equilibrium does not
depend on the temperature.30.The addition of nitric acid increases the solubil-
ity of which of the following compounds?
(A) KCl(s)
(B) Pb(CN) 2 (s)
(C) Cu(NO 3 ) 2 (s)
(D) NH 4 NO 3 (s)
(E) FeSO 4 (s)31.The Kspfor Mn(OH) 2 is 1.6 × 10 −^13. What is the
molar solubility of this compound in water?(A)(B)1.6 × 10 −^13(C)(D)
(E) 4.0 × 10 −^14(^2) 40 10. × − 14
(^3) 40 10. × − 13
(^3) 40 10. × − 14