1.
The following data were obtained for the reaction between compounds X and Y. The initial concentrations are in molecules cm–3
and the initial rates are in molecules cm–3 s–1.
[X]0
[Y]0
Initial rate

A.
Rate = k [X] [Y]
B.
Rate = k [X] 2 [Y]
C.
Rate = k [X] [Y]2
D.
Rate = k [X]2
E.
Rate = k [X]2 [Y]2


2.
At a certain instant the rate of disappearance of O2 in the reaction,

              4 NH3 (g)   +   7 O2 (g)   →   4 NO2 (g)   +   6 H2O (g)

is X. The rate of appearance of water at the same instant is:
A.
1.2 X
B.
1.1 X
C.
0.86 X
D.
0.57 X
E.
1.5 X


3.
A first-order reaction is 35% complete after 25 minutes. The half-life of this reaction is:
A.
40.2 min
B.
16.5 min
C.
60.2 min
D.
23.8 min
E.
35.7 min


4.
What is the expected overall rate law for a reaction that follows the mechanism:
 
step 1 (very slow)
 
A2 + B2 → R + C
 
step 2 (fast)
 
A2 + R → C
 
A.
rate = k[A2]2
B.
rate = k[A2]
C.
rate = k[R]2
D.
rate = k[A2][R]
E.
rate = k[A2][B2]


5.
The reaction

            2 H2O2 →   2H2O   +   O2

has the following mechanism:
H2O2 + I – →   H2O + IO –
 
H2O2 + IO – → H2O + O2 + I –
 
     
The catalyst in the reaction is:
A.
H2O
B.
I –
C.
H2O2
D.
IO –
E.
O2


6.
The equilibrium constant expression for the reaction,

                      H2 (g) + I2 (s) 2 HI (g)

is:
A.
B.
C.
D.
E.


7.
An equal number of moles of A2 and B2 was reacted at 2000 according to the equation,
A2 (g)    +    B2 (g)     2 AB (g)

When equilibrium was reached the concentration of AB was 0.50 M. What is the concentration of B2 at equilibrium? [ is 25.0 at 2000 ]

A.
0.10   M
B.
0.14   M
C.
0.049 M
D.
0.35   M
E.
0.010 M


8.
A sample of solid NH4NO3 in an evacuated container decomposed on heating according to the equation:

   

At equilibrium the total pressure in the container was found to be 3.66 atm at a temperature of 500.oC. Calculate Kp.
A.
1.49
B.
2.98
C.
1.82
D.
7.26
E.
0.0196


9.
For the equilibrium system

                               2 A (g)     2 B (g)    +     C (g)

at a certain temperature . If 2.0 moles of A are initially placed in a 1.0-L flask determine the concentration of C when equilibrium is reached at the same temperature.
A.
0.014   M
B.
0.028   M
C.
0.033   M
D.
0.042   M
E.
0.0087 M


10.
Which of the following statements for the equilibrium,
2 H2 (g)   +   X2 (g) 2 H2X(g)      ;      

is not true?
A.
Addition of H2 will cause the H2X concentration to increase.
B.
Addition of the inert gas Argon will not affect the equilibrium.
C.
Increasing the pressure (by decreasing the volume) produces more H2X.
D.
Decreasing the pressure (by increasing the volume) produces more H2X.
E.
Increasing the temperature will cause some of the H2X to change to H2 and X2.


11.
Solid calcium hydroxide, [Ca(OH)2], is dissolved in water until the pH of the solution is 10.12. The calcium ion (Ca2+) concentration is:
A.
  M
B.
  M
C.
  M
D.
  M
E.
M


12.
The equilibrium constant for the ionization of the acid HF is . What would the % ionization of a 5.00 M HF solution be?
A.
1.24   %
B.
9.60   %
C.
6.48   %
D.
0.084 %
E.
1.88   %


13.
Which solution will have the lowest pH?
A.
0.10 M NH3
B.
0.10 M HNO3
C.
0.10 M NaCl
D.
0.10 M H2CO3
E.
0.10 M NaOH


14.
What is the pH of a 0.20 M solution of NH4Cl? [Kb(NH3) = 1.8 × 10–5]
A.
3.74
B.
4.98
C.
6.53
D.
9.02
E.
10.25


15.
Which of the compounds in the following table is most soluble?

Compound
BaSO4
CoS
PbSO4
AgBr
PbI2
 
A.
BaSO4
B.
CoS
C.
PbSO4
D.
AgBr
E.
PbI2


16.
For hydrosulfuric acid (H2S) and . Determine the concentration of the sulfide ion () in a 0.20 M hydrosulfuric acid solution.
A.
0.20           M
B.
M
C.
M
D.
M
E.
M


17.
Calculate the pH of a buffer solution that contains 0.10 M benzoic acid (C6H5COOH) and 0.56 M sodium benzoate (C6H5COONa). [ for benzoic acid.]
A.
10.56
B.
11.36
C.
3.44
D.
4.94
E.
4.44


18.
The pH at the equivalence point of an acid-base titration depends on:
A.
The initial concentration of the standard solution.
B.
The indicator used.
C.
The self-ionization of water.
D.
The pH of the solution of unknown concentration.
E.
The hydrolysis of the salt formed.


19.
25.0 L of 0.15 M NH3 are added to 50.0 L of 0.0020 M Zn(H2O)42+. Given,

Zn(H2O)42+ (aq) + 4 NH3 (aq) Zn(NH3)42+ (aq) + 4 H2O (l) ;            

calculate the concentration of Zn(H2O)42+.
A.
B.
C.
D.
E.


20.
Over what range of pH is a HOCl – NaOCl buffer effective?
( for HOCl is )
A.
pH 2.0 – pH 4.0
B.
pH 7.5 – pH 9.5
C.
pH 6.5 – pH 8.5
D.
pH 6.5 – pH 9.5
E.
pH 1.0 – pH 14.0


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