108-2nd Chem Exam (A)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The photoelectric effect is __________.
A) the production of current by silicon solar cells when exposed to sunlight B) the darkening of photographic film when exposed to an electric field C) the total reflection of light by metals giving them their typical luster D) a relativistic effect
E) the ejection of electrons by a metal when struck with light of sufficient energy Answer: E
2) In the Bohr model of the atom, __________.
A) electron energies are quantized
B) electron paths are controlled by probability C) electrons can have any energy
D) electrons travel in circular paths called orbitals E) both A and C
Answer: A
3) Of the following transitions in the Bohr hydrogen atom, the __________ transition results in the emission of the highest-energy photon.
A) n = 6 n = 3 B) n = 6 n = 1 C) n = 1 n = 4 D) n = 3 n = 6 E) n = 1 n = 6 Answer: B
4) The uncertainty principle states that __________.
A) there can only be one uncertain digit in a reported number B) it is impossible to know how many electrons there are in an atom C) it is impossible to know anything with certainty
D) it is impossible to know the exact position and momentum of an electron E) matter and energy are really the same thing
Answer: D
5) Which one of the following is not a valid value for the magnetic quantum number of an electron in a 5d subshell?
A) 3 B) 0 C) 2 D) 1 E) -1
Answer: A
6)An electron cannot have the quantum numbers n = __________, l = __________, ml = __________.
A) 1, 0, 0 B) 6, 1, 0 C) 3, 2, 3 D) 3, 2, -2 E) 3, 2, 1
Answer: C
7) Which electron configuration represents a violation of the Pauli exclusion principle?
A)
B)
C)
D)
E)
Answer: B
8) The ground state electron configuration of Ga is __________.
A) [Ar]4s23d11
B) 1s22s22p63s23p64s23d104p1 C) 1s22s22p63s23p64s23d104d1 D) 1s22s22p63s23p64s24d104p1
E) 1s22s23s23p64s23d104p1 Answer: B
9) What is the frequency (s-1) of a photon that has an energy of 4.38 × 10-18 J?
Rydberg constant = 1 .096776 × 107 m-1 ; Planck constant = 6.626 × 10-34 J-s
A) 1.45 × 10-16 B) 1.31 × 10-9 C) 6.61 × 1015 D) 436 E) 2.30 × 107 Answer: C
10) The n = 8 to n = 4 transition in the Bohr hydrogen atom occurs in the __________ region of the electromagnetic spectrum.
Rydberg constant = 1 .096776 × 107 m-1 ; Planck constant = 6.626 × 10-34 J-s
A) microwave B) X-ray C) infrared D) visible E) ultraviolet
Answer: C
11) Which of the following has eight valence electrons?
A) Kr B) Na+
C) Ti4+
D) Cl-
E) all of the above
The diagram below is the Born-Huber cycle for the formation of crystalline potassium fluoride.
12) Which energy change corresponds to the electron affinity of fluorine?
A) 1 B) 6 C) 5 D) 2 E) 4
Answer: E
13) Of the molecules below, the bond in __________ is the most polar.
A) HBr B)H2 C) HF D) HI E) HCl
Answer: C
14) The bond length in an HI molecule is 1.61 Å and the measured dipole moment is 0.44 D. What is the magnitude (in units of e) of the negative charge on I in HI?
(1 debye = 3.34 × 10-30 coulomb-meters; e=1.6 × 10-19 coulombs)
A) 0.057 B) 0.22 C) 1 D) 9.1 E) 1.6 × 10-19
Answer: A
15) Resonance structures differ by __________.
A) number of electrons only B) number of atoms only
C) number and placement of electrons D) placement of electrons only
E) placement of atoms only Answer: D
16)Given that the average bond energies for C-H and C-Br bonds are 413 and 276 kJ/mol, respectively, the heat of atomization of bromoform (CHBr3) is __________ kJ/mol.
A) 1241 B) -1378 C) -689 D) 1378 E) 689
Answer: A
17) In the Lewis structure of HCO3-, the formal charge on H is __________ and the formal charge on C is __________.
A) 0, 0 B) 0, -1 C) +1, -1 D) -1, -1 E) -1, +1
Answer: A
18)How many equivalent resonance forms can be drawn for SO2 without expanding octet on the sulfur atom (sulfur is the central atom)?
A) 1 B) 3 C) 2 D) 4 E) 0
Answer: C
19) The Lewis structure of the CO32- ion is __________.
A)
B)
C)
D)
E)
Answer: B
20) Using the table of average bond energies below, the H for the reaction is __________ kJ.
H-C C-H (g) + H-I (g) H2C CHI (g)
Bond: C C C=C H-I C-I C-H
D (kJ/mol): 839 614 299 240 413
A) -931 B) +506 C) -506 D) +129 E) -129
Answer: E
21) At what velocity (m/s) must a 20.0 g object be moving in order to possess a kinetic energy of 1.00 J?
A) 100 × 102 B) 50.0 C) 1.00 × 103 D) 10.0 E) 1.00
Answer: D
22) The internal energy of a system __________.
A) refers only to the energies of the nuclei of the atoms of the component molecules B) is the sum of the potential and kinetic energies of the components
C) is the sum of the kinetic energy of all of its components
D) is the sum of the rotational, vibrational, and translational energies of all of its components E) none of the above
Answer: B
23) Which one of the following is an exothermic process?
A) ice melting B) water evaporating C) boiling soup
D) condensation of water vapor
E) Ammonium thiocyanate and barium hydroxide are mixed at 25 °C: the temperature drops.
Answer: D
24) Of the following, which one is a state function?
A) heat B) q D) wC) H
E) none of the above Answer: C
25) A sample of calcium carbonate [CaCO3 (s)] absorbs 45.5 J of heat, upon which the temperature of the sample increases from 21.1 °C to 28.5 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, what is the mass (in grams) of the sample?
A) 5.0 x 103 B) 7.5 C) 410 D) 3.7 E) 5.0
Answer: B
26) The reaction
4Al (s) + 3O2 (g) 2Al2O3 (s) H° = -3351 kJ is __________, and therefore heat is __________ by the reaction.
A) exothermic, absorbed B) endothermic, released C) exothermic, released D) endothermic, absorbed
E) thermoneutral, neither released nor absorbed Answer: C
27) Consider the following two reactions:
A 2B H°rxn = 456.7 kJ/mol A C H°rxn = -22.1kJ/mol Determine the enthalpy change for the process:
2B C A) 434.6 kJ/mol
B) -478.8 kJ/mol C) 478.8 kJ/mol D) -434.6 kJ/mol
E) More information is needed to solve the problem.
Answer: B
28)For the species in the reaction below, Hf° is zero for __________.
2Co (s) + H2 (g) + 8PF3 (g) 2HCo(PF3)4 (l) A)H2 (g)
B) Co (s)
C)HCo(PF3)4 (l) D)PF3 (g)
E)both Co(s) and H2 (g) Answer: E
29) Given the data in the table below, H°rxn for the reaction 4NH3 (g) + 5O2 (g) 4NO (g) + 6H2O (l) is __________ kJ.
Substance Hf° (kJ/mol)
H2O (l) -286
NO (g) 90
NO2 (g) 34
HNO3 (aq) -207
NH3 (g) -46
A) -1172 B) -1892 C) -1540 D) -150
E)The Hf° of O2 (g) is needed for the calculation.
Answer: A
30) A slice of apple pie contains 14.0 grams of fat, 2.00 grams of protein, and 52.0 grams of carbohydrate. The respective fuel values for protein, fat, and carbohydrate are 17, 38, and 17 kJ/g, respectively. If cycling typically burns 1000.0 kJ/hour, __________ minutes of cycling are required to completely burn off the slice of pie.
A) 8.25 B) 87.0
C) less than one minute D) 4.66
E) 1.45 Answer: B
31) The atomic radius of main-group elements generally increases down a group because __________.
A) effective nuclear charge decreases down a group B) effective nuclear charge increases down a group
C) the principal quantum number of the valence orbitals increases D) effective nuclear charge zigzags down a group
E) both effective nuclear charge increases down a group and the principal quantum number of the valence orbitals increases
Answer: C
32) Of the following, which gives the correct order for atomic radius for Mg, Na, P, Si and Ar?
A) Na > Mg > Si > P > Ar B) Si > P > Ar > Na > Mg C) Ar > P > Si > Mg > Na D) Mg > Na > P > Si > Ar E) Ar > Si > P > Na > Mg Answer: A
33) Which of the following is an isoelectronic series?
A) F-, Cl-, Br-, I- B) S, Cl, Ar, K C) O2-, F-, Ne, Na+
D) Si2-, P2-, S2-, Cl2- E) B5-, Si4-, As3-, Te2- Answer: C
34) Which of the following correctly represents the third ionization of aluminum?
A) Al-2 (g) + e- Al3- (g) B) Al+2 (g) + e- Al3+ (g) C) Al (g) Al+ (g) + e- D) Al+2 (g) + e- Al+1 (g)
E) Al+2 (g) Al3+ (g) + e- Answer: E
35) Of the following elements, __________ has the most negative electron affinity.
A) Al B) B C) P D) Si E) Cl
Answer: E
36) Of the elements below, __________ is the most metallic.
A) Mg B) Al C) Ar D) K E) Na
Answer: D
37) Consider the general valence electron configuration of ns2np5 and the following statements:
(i) Elements with this electron configuration are expected to form -1 anions.
(ii) Elements with this electron configuration are expected to have large positive electron affinities.
(iii) Elements with this electron configuration are nonmetals.
(iv) Elements with this electron configuration form acidic oxides.
Which statements are true?
A) (i) and (ii) B) (i), (iii,) and (iv) C) (ii) and (iii) D) (i), (ii), and (iii)
E) All statements are true.
Answer: B
38) __________ is credited with developing the concept of atomic numbers.
A) Henry Moseley B) Dmitri Mendeleev C) Ernest Rutherford D) Michael Faraday
E) Lothar Meyer Answer: A
39) Consider the following properties of an element:
(i) It is solid at room temperature.
(ii) It easily forms an oxide when exposed to air.
(iii) When it reacts with water, hydrogen gas evolves.
(iv) It must be stored submerged in oil.
Which element fits the above description the best?
A) sulfur B) sodium C) copper D) magnesium E) mercury
Answer: B
40) All of the following are ionic compounds except __________.
A)Li3N B)K2O C)SiO2 D) NaCl E)Na2SO4
Answer: C
