338 STEP 5. Build Your Test-Taking Confidence
- B—All but B and D are Lewis bases. The higher
charge on iron makes the difference - C—In general, the more oxygens present, the
stronger the oxyacid. - C—Only C can be oxidized.
- B—The phenolphthalein is the source of the
color change. - A—If the numbers of protons are equal, the
atoms are isotopes. - A—Anions are usually larger than cations. S is
lower on the periodic table than O. - C—Solutions do not readily separate.
- D—This is a property of aluminum.
- B—The precipitate is CaCO 3.
- C—Iron slowly hydrolyzes to form solid
Fe(OH) 3. - A—Soluble compounds and spectator ions
should not be present. - E—A and C precipitate PbCl 2. B precipitates
PbCrO 4. D precipitates Al(OH) 3. - B—BaSO 4 forms.
- E—(50.0 mL)(0.600 mol KOH/1000 mL)(1 mol
H 2 SO 4 /2 mol KOH) (1000 mL/0.300 mol
H 2 SO 4 ) - C—(25 g (NH 4 ) 2 SO 4 )(1 mol(NH 4 ) 2 SO 4 /132 g
(NH 4 ) 2 SO 4 )(8 mol H/1 mol (NH 4 ) 2 SO 4 )
(1 g H/ mol H) - B—(4.64 g oxide)(l mol oxide/232 g mol O 2 /2
mol oxide) =0.00927 mol - A—4 C 4 H 11 N(l) +27 O 2 (g) →16 CO 2 (g) +
22 H 2 O(l) +2 N 2 (g) - B—KMnO 4 is the limiting reactant.
- C—2 C 8 H 18 +25 O 2 →6 CO 2 +18 H 2 O
- B—(0.0100 mol Ra)(1 mol H 2 /1 mol Ra)(22.4 L/
mol H 2 ) =0.224 L - E—The average kinetic energy, not the average
speed, is the same. - E—Use Graham’s law.
- E—Definition
- C—Kinetic molecular theory
- A—Definition—a property of free energy
- B—Definition
- B—This is an exothermic process, and exother-
mic processes do not proceed as well at higher
temperatures. - B—The reaction that has the greatest increase in
the number of moles of gas. - E—To become spontaneous at a lower tempera-
ture means entropy impeded the reaction
(entropy was negative). The enthalpy must be
negative. Nonspontaneous under standard condi-
tions means: ΔG>0. - D—Subtract 54 × 2 mol N 2 O 5 from the
observed value (use Hess’s law). - B—These have completely filled shells or
subshells—all the electrons are paired =diamagnetic. - A—No such thing as a 1p orbital.
- D—All halogens are ns^2 np^5.
- B—A partially filled d orbital is required with an
s^1 or s^2. - C—This is V^2 +.
- D—Definition
- E—The electrons enter the orbitals separately
(unpaired) until forced to pair. Unpaired =
paramagnetic. - A—Application of the definition.
- B—This is a consequence of the better shielding
of d electrons over s electrons. - C—There are only single bonds (σ) present.
Answers and Explanations for Exam 2—Multiple Choice