Download 21Sc , 48 22Ti , 50 22Ti , 50

NOTE: This ‘practice exam’ contains more than questions than the real final.
1. The wavelength of light emitted from a green laser pointer is 5.32 × 102 nm. What is the wavelength in meters?
2. What is the correct answer, with correct significant figures, to the following expression: (18 + 95) × 0.077351?
3. At 25 ºC, the density of oxygen in air is 0.275 g/L. What volume is occupied by 25 kg of oxygen at 25 °C?
4. How many protons, neutrons, and electrons are in an oxygen-18 atom?
a) 6 protons, 8 neutrons, 4 electron
b) 6 protons, 10 neutrons, 8 electrons
c) 8 protons, 8 neutrons, 8 electrons
d) 8 protons, 10 neutrons, 8 electrons
e) 8 protons, 10 neutrons, 18 electrons
5. What is the identity of
72
32
X?
6. Which two of the following atoms are isotopes?
45
48
50
50
21 Sc , 22Ti , 22Ti , 23V
7. Bromine has two naturally occurring isotopes. The average mass of bromine is 79.904 u. If 50.54% of bromine is found
as bromine-79 (78.9183 u), what is the mass of the other isotope?
8. You have 0.330 mole of each of the following elements: Be, B, Br, Ba, and Bi. Which sample has the largest mass?
9. A 3.6 g sample of lithium contains ________ atoms.
10. How many elements are in the fifth period of the periodic table?
11. What is the correct formula for an ionic compound that contains magnesium ions and fluoride ions?
12. What is the correct name for NH4ClO4?
13. What is the correct name for Cr(NO3)2?
14. What is the correct name for PF5?
15. What is the mass percent of chlorine in iron(II) chloride?
16. A molecule is found to contain 47.35% C, 10.60% H, and 42.05% O. What is the empirical formula for this molecule?
17. An organic solvent has the empirical formula CH. If the molar mass of this solvent is 78.11 g/mol, what is the molecular
formula of benzene?
18. Ammonia is prepared by reacting nitrogen and hydrogen gases at high temperature according to the unbalanced chemical
equation below.
__ N2(g) + __ H2(g) → __ NH3(g)
What are the respective coefficients when the equation is balanced with the smallest whole numbers?
19. What is the net ionic equation for the reaction of aqueous sodium carbonate with aqueous iron(III) chloride?
e) CO32-(aq) + Cl-(aq) → CO2(g) + Cl2O(s)
20. Dinitrogen trioxide, a blue solid, dissociates to form nitrogen monoxide and nitrogen dioxide gases. What mass of
nitrogen dioxide is formed from the decomposition of 13.1 g of N2O3?
21. Magnesium reacts with iodine gas at high temperatures to form magnesium iodide. What mass of MgI2 can be produced
from the reaction of 4.44 g Mg and 13.4 g I2?
22. If 2.891 g MgCl2 is dissolved in enough water to make 500.0 mL of solution, what is the molarity of the magnesium
chloride solution?
23. A 25.00 mL sample of NaOH is titrated with 17.13 mL of 0.3150 M HCl. What is the concentration of the NaOH
solution?
24. The thermochemical equation for the combustion of hexane is shown below.
C6H14(g) + 19/2 O2(g) → 6 CO2(g) + 7 H2O(g)
ΔH° = -4163 kJ
What is the enthalpy change for the combustion of 2.50 g C6H14?
26. If 46.1 g Zn at 18.0 °C is placed in 80.0 g H2O at 75.0 °C, what is the final temperature of the mixture? The specific heat
capacities of zinc and water are 0.388 J/g·K and 4.184 J/g·K, respectively.
27. What is the wavelength of radiation that has a frequency of 2.10 × 1014 s −1?
28. The ________ of a photon of light is ________ proportional to its frequency and ________ proportional to its
wavelength.
29. What is the energy in joules of a mole of photons associated with red light of wavelength 7.00 × 102 nm?
30. Which of the following types of experiments demonstrate that an electron has the properties of a particle?
a) nuclear fission
b) electron diffraction
c) light emission from atomic gases
d) mass spectroscopy
e) photoelectric effect
31. Which of the following sets of quantum numbers refers to a 4p orbital?
a) n = 1, l = 1, ml = -1
b) n = 1, l = 2, ml = -1
c) n = 4, l = 1, ml = 0
d) n = 4, l = 2, ml = -1
e) n = 4, l = 3, ml = +2
32. All of the following sets of quantum numbers are allowed EXCEPT
a) n = 6, l = 0, ml = +1
b) n = 5, l = 4, ml = 0
c) n = 4, l = 1, ml = -1
d) n = 3, l = 2, ml = +2
e) n = 1, l = 0, ml = 0
33. Which of the following diagrams represent p-orbitals?
(I)
a) (I) only
(II)
b) (II) only
(III)
(IV)
c (III) only
34. The Pauli exclusion principle states that
a) no two electrons in an atom can have the same spin.
b) electrons can have either ±½ spins.
c) electrons with opposing spins are attracted to each other.
d) (IV) only
e) (I) and (II)
d) no two electrons in an atom can have the same four quantum numbers.
e) atoms with no unpaired electrons are diamagnetic.
35. Which element has the electron configuration 1s22s22p63s23p4?
36. For which of the following atoms is the common ion paramagnetic?
a) H
b) Al
c) Mg
d) Ni
e) F
37. Which of the following ions have the same ground state electron configuration: Sn4+, Pb4+, Sr2+, and Br-?
38. Which one of the following statements is INCORRECT?
a) Ionization energy is always a positive value.
b) Ionization energy is the energy required to remove an electron from a gaseous atom.
c) For any element, the second ionization energy is larger than the first ionization energy.
d) Ionization energy decreases across a periodic of the periodic table.
e) Ionization energy decreases down a group of the periodic table
39. In general, atomic radii
a) decrease down a group and remain constant across a period.
b) decrease down a group and increase across a period.
c) increase down a group and increase across a period.
d) increase down a group and remain constant across a period.
e) increase down a group and decrease across a period.
40. Which combination of atoms is most likely to produce a compound with ionic bonds?
a) Al and F
b) P and H
c) C and O
d) Si and O
e) S and Br
41. What is the correct Lewis structure for IF3?
42. Use VSEPR theory to predict the molecular geometry of IF5.
43. What are the bond angles in ClO4-?
44. Which one of the following molecules has a dipole moment?
a) CI4
b) PF5
c) NCl3
d) SO3
45. How many sigma (σ) bonds and pi (π) bonds are in the following molecule?
H
H
C
H
C
H
a)
b)
c)
d)
C
C
H
H
two σ and nine π
two σ and seven π
seven σ and two π
nine σ and two π
46. What is the hybridization of the sulfur atom in SF4?
47. How many electrons, protons and neutrons does 87Sr2+ have?
48. What is the formula of maganese (VII) oxide?
e) O2
49. What is the empirical formula of the ionic compound that forms between calcium and fluorine?
50. What is the quantity of Fe2O3 that will be produced if 5.00 g of FeS2 is reacted with 11.0 g of oxygen according to the
following reaction:
4 FeS2(s) + 11 O2(g) --> 2 Fe2O3(s) + 8 SO2(g)
51. The mineral corundum (which is the host structure for sapphires and rubies) has the formula Al2O3. If the density of
corundum is 3.97 g/cm3 how many aluminum atoms are contained in a corundum crystal with a volume of 0.250 cm3?
52.Balance the following equation.
_ PCl5(l) + _ H2O(l) --> _ H3PO4(aq) + _ HCl(aq)
53. Which of the following compounds is not a strong electrolyte?
(a) KClO3
(b) H2SO4
(c) KOH
(d) NH4Br
(e) C2H5OH
54. If 258 mL of a 0.500 M AgNO3 solution is mixed with 500 mL of a 0.312 M NaCl solution, what is the identity and mass
of the precipitate that is formed?
55. Which of the following metals will not dissolve in acid to produce hydrogen gas, H2?
•
•
•
•
•
(a) Fe
(b) Ag
(c) K
(d) Both (a) and (c)
(e) None of the above
Given a chunk of an unknown element you perform the following experiments:
•
•
•
If you drop it into a graduated cylinder containing water, the level of the water raises from 50.0 mL to 58.0 mL.
Using a digital balance you measure the mass to be 18.56 g.
Using a calorimeter you determine that 1303 J of heat is required to raise the temperature from 25° C to 125° C.
Use this information to answer the following two questions:
56. What is the density of this element?
57. What is the specific heat of this element?
58. From the following enthalpies of reaction:
2C2H6(g) + 7O2(g) --> 4CO2(g) + 6H2O(l)
C(s) + O2(g) --> CO2(g)
H = -394 kJ
2H2(g) + O2(g) --> 2H2O(l)
H = -572 kJ
Calculate DH for the following reaction.
2C(s) + 3H2(g) --> C2H6(g)
H = -3120 kJ
59. Ozone (O3) exothermically decomposes to give oxygen (O2) according to the following reaction:
2O3(g) --> 3O2(g)
H = -285.4 kJ
How much heat will be released by the decomposition of 15.0 g of ozone?
60. Increasing the intensity of a light source will have which of the following effects.
•
•
•
•
•
(a) It will increase the flux (number/sec) of photons being emitted
(b) It will increase the energy of the photons being emitted
(c) It will increase the frequency of the photons being emitted
(d) It will decrease the wavelength of the photons being emitted
(e) All of the above
61. What is the proper electron configuration for Fe3+?
62. How many electrons in a gallium atom (Ga) have a magnetic quantum number ml = 2?
63. What is the wavelength of a photon with an energy of 8.66 x 10-19 J?
64. Arrange the following atoms in order of increasing first ionization energy: Ne, Ar, S, P, As, Ca.
65. Arrange the following atoms in order of increasing electron affinity: Br, As, Se, Kr.
66. Arrange the following atoms in order of increasing atomic radius: B, Ca, Ga and Cs.
67. Predict which molecule will have the shortest C-O bond?
•
•
•
•
•
(a) CO32(b) CO2
(c) H2CO
(d) Both (b) and (c)
(e) All three, (a), (b) and (c)
68. What is the oxidation state of chlorine in perchloric acid, HClO4?
69. What is the formal charge on chlorine in the perchlorate ion, ClO4-?
70. Estimate
H for the reaction between formaldehyde and chlorine to form phosgene and hydrogen :
H2CO(g) + Cl2(g) --> Cl2CO(g) + H2(g)
Using the following bond enthalpies as necessary:
C–O 358 kJ/mol
H–H 436 kJ/mol
C= O 799 kJ/mol
C–H 413 kJ/mol
C–Cl 328 kJ/mol
Cl-Cl 242 kJ/mol
71. Which of the following ionic compounds would you expect to have the largest lattice energy?
•
•
•
•
•
(a) KCl
(b) RbBr
(c) CsI
(d) SrSe
(e) CaO
72. Which of the following molecules does not violate the octet rule?
•
•
•
•
•
(a) NO2
(b) GeF4
(c) TeF4
(d) BCl3
(e) XeF4
73. Based on the Lewis dot structures, predict the ordering of N–O bond lengths in the following molecules: NO+, NO2- and
NO3-.
74. Using VSEPR theory, predict the electron domain and molecular geometry of SF4.
75. Using VSEPR theory, predict the electron domain and molecular geometry of IF3.
76. What is the hybrid orbital set used by the carbon atom in the molecule H2CO?
77. Which of the following molecules is not linear.
•
•
•
•
•
(a) KrF2
(b) HCN
(c) SO2
(d) CO2
(e) both a and c
78. Which of the following molecules are polar?
•
•
•
•
•
(a) CH4
(b) CCl4
(c) CF4
(d) CH3Cl
(e) C2H4
79. Use formal charges to determine the most stable Lewis dot structure for N2O.
80. Consider the reaction between Na2CO3(aq) and MgSO4(aq) that results in the formation of solid magnesium carbonate
and aqueous sodium sulfate. Include the state of matter for each reaction.
Write the complete balanced molecular reaction.(3 pts)
Write the complete ionic reaction.(4 pts)
Write the net ionic equation.(3 pts)
Identify the spectator ion(s).(3 pts)