(^24) › STEP 2. Determine Your Test Readiness
- A chemist needs 800.0 mL of a 0.50 M bromide
ion, Br-, solution. She has 800.0 mL of a 0.20 M
KBr solution. How many moles of solid MgBr 2
will she need to add to increase the concentration
to the desired value?
(A) 0.24
(B) 0.50
(C) 0.30
(D) 0.12 - How many grams of HNO 3 (molecular weight
63.0) are in 500.0 mL of a 5.00 M solution?
(A) 31.5 g
(B) 63.0 g
(C) 5.00 g
(D) 158 g - If a solution of ethyl ether, (C 2 H 5 ) 2 O, in ethanol,
C 2 H 5 OH, is treated as an ideal solution, what is
the mole fraction of ethyl ether in the vapor over an
equimolar solution of these two liquids? The vapor
pressure of ethyl ether is 480 mm Hg at 20°C, and
the vapor pressure of ethanol is 50 mm Hg at this
temperature.
(A) 0.50
(B) 0.76
(C) 0.91
(D) 0.27
Chapter 14
- Step 1: 2 NO 2 (g) → N 2 (g) + 2 O 2 (g)
Step 2: 2 CO(g) + O 2 (g) → 2 CO 2 (g)
Step 3: N 2 (g) + O 2 (g) → 2 NO(g)
The above represents a proposed mechanism
for the reaction of NO 2 with CO. What are the
overall products of the reaction?
(A) NO and CO 2
(B) O 2 and CO 2
(C) N 2 and NO
(D) NO only
- 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
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 × 106The 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-]^2Chapter 15
- 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 - - 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 information from the preceding table,
which of the following is the best choice for pre-
paring a pH = 8.5 buffer?
(A) K 2 HPO 4 + K 3 PO 4
(B) K 2 HPO 4 + KH 2 PO 4
(C) K 3 PO 4
(D) K 2 HPO 4 - 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 × 10 -^4
(B) 2 × 10 -^10
(C) 7 × 10 -^8
(D) 1 × 10 -^6