1091 2nd Midterm Exam _12/09/20 (B)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The value of ΔE for a system that performs 111 kJ of work on its surroundings and gains 89 kJ of heat is __________ kJ.
A) 200 B) -111 C) -200 D) 22 E) -22
Answer: E
2) Which one of the following is an endothermic process?
A) Both A and C B) water freezing
C) Hydrochloric acid and barium hydroxide are mixed at 25 °C: the temperature increases.
D) ice melting E) boiling soup Answer: A
3) Which of the following statements is false?
A) Enthalpy is an intensive property.
B) The enthalpy change for a reaction is equal in magnitude, but opposite in sign, to the enthalpy change for the reverse reaction.
C) Internal energy is a state function.
D) The enthalpy of a reaction is equal to the heat of the reaction.
E) The enthalpy change for a reaction depends on the state of the reactants and products.
Answer: A
4) The temperature of a 12.58 g sample of calcium carbonate [CaCO3 (s)] increases from 23.6 °C to 38.2 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, how many joules of heat are absorbed?
A) 0.82 B) 5.0 C) 151 D) 410 E) 7.5
Answer: C
5) For which one of the following reactions is ΔH°rxn equal to the heat of formation of the product?
A) (1/2)N2 (g) + O2 (g) → NO2 (g) B) 6C (s) + 6H (g) → C6H6 (l) C) N2 (g) + 3H2 (g) → 2NH3 (g)
D) 6C (g) + 11H2 (g) + 11O (g) → C6H22O11 (g) E) P (g) + 4H (g) + Br (g) → PH4Br (l)
Answer: A
6) The value of ΔH° for the reaction below is -482 kJ. Calculate the heat (kJ) released to the surroundings when 38.5 g of O2 (g) reacts with excess CO.
2CO (g) + O2 (g) → 2CO2 (g)
A) 2.65 × 103 B) 482 C) 65.7 D) 580. E) 210.
Answer: D
7) ΔH for the reaction
IF5 (g) → IF3 (g) + F2 (g) is __________ kJ, give the data below.
IF (g) + F2 (g) → IF3 (g) ΔH = -390 kJ IF (g) + 2 F2 (g) → IF5 (g) ΔH = -745 kJ
A) +35 B) -1135 C) +1135 D) -35 E) +355
Answer: E
8) For which one of the following reactions is the value of ΔH°rxn equal to ΔHf° for the product?
A) C (diamond) + O2 (g) → CO2 (g) B) 2Ca (s) + O2 (g) → 2CaO (s) C) 2C (graphite) + O2 (g) → 2CO (g) D) C2H2 (g) + H2 (g) → C2H4 (g)
E) 3Mg (s) + N2 (g) → Mg3N2 (s) Answer: E
9) Which one of the following conditions would always result in an increase in the internal energy of a system?
A) The system loses heat and has work done on it by the surroundings.
B) The system loses heat and does work on the surroundings.
C) The system gains heat and has work done on it by the surroundings.
D) The system gains heat and does work on the surroundings.
E) None of the above is correct.
Answer: C
10) A 22.44 g sample of iron absorbs 180.8 J of heat, upon which the temperature of the sample increases from 21.1 °C to 39.0 °C. What is the specific heat of iron?
A) 0.900 B) 0.450 C) 0.820 D) 0.140 E) 0.840
Answer: B
11) Screening of the nuclear charge by core electrons in atoms is __________.
A) responsible for a general decrease in atomic radius going down a group B) essentially identical to that by valence electrons
C) more efficient than that by valence electrons D) less efficient than that by valence electrons
E) both essentially identical to that by valence electrons and responsible for a general decrease in atomic radius going down a group
Answer: C
12) Atomic radius generally increases as we move __________.
A) up a group and from left to right across a period B) down a group and from left to right across a period C) up a group and from right to left across a period D) down a group and from right to left across a period
E) down a group; the period position has no effect Answer: D
13) Of the following, which gives the correct order for atomic radius for Ca, K, As, Ge and Kr?
A) K > Ca > Ge > As > Kr B) Ca > K > As > Ge > Kr C) Ge > As > Kr > K > Ca D) Kr > Ge > As > K > Ca
E) Kr > As > Ge > Ca > K Answer: A
Consider the following electron configurations to answer the questions that follow:
(i) 1s2 2s2 2p6 3s1 (ii) 1s2 2s2 2p6 3s2 (iii) 1s2 2s2 2p6 3s2 3p1 (iv) 1s2 2s2 2p6 3s2 3p4 (v) 1s2 2s2 2p6 3s2 3p5
14) The electron configuration belonging to the atom with the highest second ionization energy is __________.
A) (i) B) (ii) C) (iii) D) (iv) E) (v)
Answer: A
15) Which isoelectronic series is correctly arranged in order of increasing radius?
A) Ca2+ < K+ < Ar < Cl- B) Ca2+ < Ar < K+ < Cl- C) Ca2+ < K+ < Cl- < Ar D) K+ < Ca2+ < Ar < Cl- E) Cl- < Ar < K+ < Ca2+
Answer: A
16) Which of the following correctly represents the second ionization of calcium?
A) Ca- (g) + e- → Ca2- (g) B) Ca+ (g) + e- → Ca (g) C) Ca (g) → Ca+ (g) + e- D) Ca+ (g) → Ca2+ (g) + e-
E) Ca+ (g) + e- → Ca2+ (g) Answer: D
17) Of the following statements, __________ is not true for oxygen.
A) Dry air is about 79% oxygen.
B) The most stable allotrope of oxygen is O2.
C) The chemical formula of ozone is O3.
D) Oxygen is a colorless gas at room temperature.
E) Oxygen forms peroxide and superoxide anions.
Answer: A
18) Which one of the following compounds produces a basic solution when dissolved in water?
A) Na2O B) SO2 C) CO2 D) O2 E) OF2
Answer: A
19) Which one of the following is not true about the alkali metals?
A) They are low density solids at room temperature.
B) They all have 2 electrons in their valence shells.
C) They all readily form ions with a +1 charge.
D) They have the lowest first ionization energies of the elements.
E) They are very reactive elements.
Answer: B
20) In the generation of most anions, the energy change (kJ/mol) that _______ an electron is ________.
A) adds, negative B) removes, negative C) adds, positive D) removes, positive
E) None of the above is correct.
Answer: A
21) Of the following transitions in the Bohr hydrogen atom, the __________ transition results in the emission of the lowest-energy photon.
A) n = 1 → n = 4 B) n = 3 → n = 6 C) n = 6 → n = 3 D) n = 1 → n = 6 E) n = 6 → n = 1 Answer: C
22) The uncertainty principle states that __________.
A) it is impossible to know anything with certainty B) matter and energy are really the same thing
C) there can only be one uncertain digit in a reported number
D) it is impossible to know the exact position and momentum of an electron E) it is impossible to know how many electrons there are in an atom Answer: D
23) Which one of the following represents an acceptable set of quantum numbers for an electron in an atom?
(arranged as n, l, ml, and ms)
A) 5, 4,- 5, 1/2 B) 1, 0, 0, 1/2 C) 3, 3, 3, 1/2 D) 3, 3, 3, -1/2 E) 2, 2, -1, -1/2 Answer: B
24) The energy (J) required for an electronic transition in a Bohr hydrogen atom from n = 2 to n = 3 is __________ J.
A) 4.00 × 10-19 B) -3.00 × 10-19 C) 4.60 × 1014 D) -7.90 × 10-19
E) 3.00 × 10-19 Answer: E
25) The de Broglie wavelength of an electron with a velocity of 6.00 × 106 m/s is __________ m. The mass of the electron is 9.11 × 10-28 g. Here, h=6.626X10-34 J-s
A) 1.21 × 10-10 B) 8.25 × 109 C) 8.25 × 1012 D) 1.21 × 10-13
E) 1.21 × 10-16
26) The wavelength of light that has a frequency of 1.20 × 1013 s-1 is __________ m.
A) 12.0 B) 25.0 C) 2.5 D) 2.50 × 10-5 E) 0.0400
Answer: D
27) Which electron configuration represents a violation of the Pauli exclusion principle?
A)
B)
C)
D)
E)
Answer: A
28) Which group in the periodic table contains elements with the valence electron configuration of ns2np1?
A) 1A (1) B) 2A (2) C) 3A (13) D) 4A (14) E) 8A (18)
Answer: C
29) The ground state electron configuration of Fe is __________.
A) 1s22s23s23p10
B) 1s22s22p63s23p64s24d6 C) 1s22s22p63s23p64s2 D) 1s22s23s23p63d6
E) 1s22s22p63s23p64s23d6 Answer: E
30) The condensed electron configuration of silicon, element 14, is __________.
A) [Ne]3s23p2 B) [He]2s42p6 C) [Ne]2p10 D) [He]2s4 E) [He]2s62p2
Answer: A
31) Which ion below has a noble gas electron configuration?
A) C2+ B) B2+ C) N2- D) Be2+ E) Li2+
Answer: D
32) In ionic bond formation, the lattice energy of ions ________ as the magnitude of the ion charges _______ and the radii __________.
A) increases, increase, decrease B) increases, increase, increase C) increases, decrease, decrease D) decreases, increase, increase
E) increases, decrease, increase Answer: A
33) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) CF4 B) SiF4 C) NF3 D) PO43- E) SeF4
Answer: E
34) The formal charge on nitrogen in NO3- is __________.
A) +1 B) 0 C) -2 D) -1 E) +2
Answer: A
35) Using the table of average bond energies below, the ΔH for the reaction is __________ kJ.
H-C≡C-H (g) + H-I (g) → H2CCHI (g)
Bond: C≡C C=C H-I C-I C-H
D (kJ/mol): 839 614 299 240 413
A) -506 B) +129 C) -931 D) -129 E) +506
Answer: D
36) What is the electron configuration for the Co2+ ion?
A) [Ar]3d5 B) [Ne]3s23p10 C) [Ar]4s23d9 D) [Ar]3d7
E) [Ar]4s13d6 Answer: D
37) Using the table of bond dissociation energies, the ΔH for the following reaction is __________ kJ.
2HCl (g) + F2 (g) → 2HF (g) + Cl2 (g) Bond D (kJ/mol)
H-Cl 431
F-F 155
H-F 567
Cl-Cl 242
A) 223 B) -359 C) -223 D) 359 E) 208
Answer: B
38) Which two bonds are least similar in polarity?
A) Al-Cl and I-Br B) O-F and Cl-F C) C-Cl and Ge-Cl D) B-F and Cl-F
E) I-Br and Si-Cl Answer: A
39) How many equivalent resonance structures can be drawn for the molecule of SO3 without having to violate the octet rule on the sulfur atom?
A) 3 B) 5 C) 1 D) 4 E) 2
Answer: A
40) Given the electronegativities below, which covalent single bond is most polar?
Element: H C N O
Electronegativity: 2.1 2.5 3.0 3.5
A) OH B) ON C) OC D) CH E) NH
Answer: A
