5 Steps to a 5 AP Chemistry

24  STEP 2. Determine Your Test Readiness

62.The difference in energy between the transition
state and the reactants is

(A) the kinetic energy

(B) the activation energy

(C) the free energy

(D) the reaction energy

(E) the heat of reaction

63.The table below gives the initial concentrations
and rates for three experiments.

INITIAL RATE
INITIAL INITIAL OF FORMATION
[ClO 2 ] [OH−] OF ClO 2 −
EXPERIMENT (mol L−^1 ) (mol L−^1 ) (mol L−^1 s−^1 )

1 0.100 0.100 2.30 × 105

2 0.200 0.100 9.20 × 105

3 0.200 0.200 1.84 × 106

The reaction is 2ClO 2 (aq) +2OH−(aq)→ ClO 2 −(aq)
+ClO 3 −(aq) +H 2 O(l). What is the rate law for this
reaction?

(A) Rate =k[ClO 2 ]^2 [OH−]^2

(B) Rate =k[ClO 2 ]

(C) Rate =k[ClO 2 ]^2 [OH−]

(D) Rate =k[OH−]^2

(E) Rate =k[ClO 2 ][OH−]

Chapter 15

64.Which of the following CANNOT behave as
both a Brønsted base and a Brønsted acid?

(A) HCO 3 −

(B) HPO 42 −

(C) HSO 4 −

(D) CO 32 −

(E) HC 2 O 4 −

65.A species, molecule, or ion is called a Lewis base
if it does which of the following?

(A) It donates an H+.

(B) It accepts an H+.

(C) It increases the H+(aq) in water.

(D) It donates a pair of electrons.

(E) It accepts a pair of electrons.

66.Acid Ka, acid dissociation constant

H 3 PO 4 7.2 × 10 −^3

H 2 PO 4 − 6.3 × 10 −^8

HPO 42 − 4.2 × 10 −^13

Using the above information, choose the best

answer for preparing a pH =8.5 buffer.

(A) K 2 HPO 4 +K 3 PO 4

(B) H 3 PO 4 +KH 2 PO 4

(C) K 3 PO 4

(D) K 2 HPO 4

(E) K 2 HPO 4 +KH 2 PO 4

67.What is the ionization constant, Ka, for a weak

monoprotic acid if a 0.5-molar solution has

a pH of 5.0?

(A) 3 ×l0−^4

(B) 2 ×l0−^10

(C) 7 ×l0−^8

(D) 1 × 10 −^6

(E) 5 ×l0−^5

Questions 68–71 refer to the following aqueous

solutions. All concentrations are 1 M.

(A) KBr (potassium bromide) and HBr (hydro-

bromic acid)

(B) H 2 C 2 O 4 (oxalic acid) and KHC 2 O 4 (potas-

sium hydrogen oxalate)

(C) NH 3 (ammonia) and NH 4 NO 3 (ammo-

nium nitrate)

(D) (CH 3 ) 2 NH (dimethylamine) and HC 2 H 3 O 2

(acetic acid)

(E) (CH 3 ) 2 NH (dimethylamine) and Ca(OH) 2

(calcium hydroxide)

68.The most acidic solution (lowest pH)

69.The solution with a pH nearest 7

70.A buffer with a pH > 7

71.A buffer with a pH < 7

72.Determine the OH−(aq) concentration in 0.0010

M pyridine (C 5 H 5 N) solution. (The Kbfor pyri-

dine is 9 × 10 −^9 .)

(A) 5 × 10 −^6 M

(B) 1 × 10 −^3 M

(C) 3 × 10 −^6 M

(D) 9 × 10 −^9 M

(E) 7 × 10 −^7 M