Session Review Quiz 1
Multiple Choice
I. Atoms/Periodicity
Choose from the following types of energy for Questions 1-2 (#26-28)
A. Free Energy B. Lattice Energy C. Kinetic Energy D. Activation Energy E. Ionization Energy
1. The energy needed to separate the ions in an ionic solid. B
2. The energy difference between the transition state and the reactants. D
3. VSEPR predicts that a BF3 molecule will be which of the following shapes? (#40) D
A. Tetrahedral
B. Trigonal bipyramidal C. Square pyramid D. Trigonal planar E. Square planar
Periodicity/Atomic Structure/Electron Configuration
1. In most of its compounds, this element exists as a monatomic cation. (#5) D
A. F
B. S
C. N
D. Ca
E. Cl
2. A ground-state electron in a calcium atom might have which of the following sets of quantum numbers? D
A. n = 3; l = 2; ml = 0; ms = -1/2
B. n = 5; l = 0; ml = 0; ms = -1/2
C. n = 4; l = 1; ml = 0; ms = -1/2
D. n = 4; l = 0; ml = 0; ms = -1/2
E. n = 4; l = 0; ml = +1; ms = -1/2
The following answers are to be used for questions 35-38 A. Pauli exclusion principle
B. Electron shielding
C. The wave properties of matter D. Heisenberg uncertainty principle E. Hund’s rule
5. The diffraction of electrons. (#35) C
6. The maximum number of electrons in an atomic orbital is two. (#36) E 7. An oxygen atom is paramagnetic in the ground state. (#37) E
9. Magnesium reacts with element X to form an ionic compound. If the ground-state electron configuration of X is 1s22s22p5, what is the simplest formula for this compound? (#39) B
A. Mg2X3
B. MgX2
C. Mg2X4
D. Mg2X5
E. MgX
10. Based on the chart below, element X is in which periodic group? C
A. Group 1A
B. Group 2A
C. Group 3A
D. Group 4A
E. Group 5A
Nuclear Chemistry
11. When decays, it emits 2 α particles, then a β particle, followed by an α particle. The resulting nucleus is: (#71) D
A. B. C. D. E.
12. Which of the following statements are correct concerning particles β? (#73) A
I. They have a mass number of zero and a charge of -1. II. They are electrons.
III. They are less penetrating than α particles
A. I and II B. I and III C. II and III D. I only E. II only
13. If 75% of a sample of pure decays in 24.6 yr, what is the half-life of ? (#74) C A. 24.6 yr
B. 18.4 yr C. 12.3 yr D. 6.15 yr E. 3.07 yr
II. Bonding
4. Which of the following does not have one or more (pi) bonds? (#40) C Ionization Energies for Element X (kJ/mol)
First Second Third Fourth Fifth
A. HNO2
B. N2
C. N2H4
D. HNO3
E. N2H2
For questions 4-5, pick the best choice from the following: A. Ionic bonds
B. Hybrid orbitals C. Resonance structures D. Hydrogen bonding E. van der Waals attractions
5. The unusually high melting point of hydrogen fluoride is due to (#41) D
7. Which of the following has more than one unshared pair of valence electrons on the central atom? (#43) A
A. NH2
-B. N2O5
C. NH3
D. NO2
-E. NO3
-8. Which types of hybridization of carbon are in the compound propane, CH3CH2CH3? (#44) A
I. sp3
II. sp2
III. sp
A. I only B. II and III C. I, II, and III D. II only E. I and II
9. The approximate boiling points for hydrogen compounds of some of the elements in the nitrogen family are: (SbH3 15 ºC), (AsH3 -62 ºC), (PH3 -87 ºC), and (NH3, -33 ºC). The best explanation for the fact that
NH3 does not follow the trend of the other hydrogen compounds is: (#45) D
A. NH3 is the only one that is nearly ideal in the gas phase.
B. NH3 is the only one that is a base.
C. NH3 is the only one that is water soluble.
D. NH3 is the only one to exhibit hydrogen bonding.
E. NH3 is the only one that is nonpolar.
10. If 87.5 percent of a sample of pure 131I decays in 24 days, what is the half-life of 131I? B
A. 6 days B. 8 days C. 12 days
D. 14 days E. 21 days
11. Correct statements about alpha particles include which of the following? D I. They have a mass number of 4 and a charge of +2
II. They are more penetrating than beta particles III. They are helium nuclei
a) I only b) III only c) I and II d) I and III e) II and III
12. The nuclide Cm is radioactive and decays by the loss of one beta particle. The product nuclide is E
a) Pu b) Am c) Cm d) Cm e) Bk
Solubility
13. At 25 ºC, the Ksp for AgCl is 1.8 x 10-10. To determine the standard free energy change at 25 ºC for the
reaction AgCl(s) Ag+(aq) + Cl-(aq), you would set up the problem as: (1-#40) D
A. x =
B. x = (1.8 x 10-10)2
C. –(8.314)(25)(ln 1.8 x 10-10)
D. –(8.314)(298)(ln 1.8 x 10-10)
14. A solution is made by adding 0.100 mol of KI and 0.0100 mol of KCl to a final volume of 0.100 L. A silver nitrate solution of unknown concentration is slowly added. Which precipitate will from first? (Ksp AgI = 8.5 x 10-17; Ksp AgCl = 1.8 x 10-10. (2-#41) B
A. AgCl
B. AgI
C. ICl
D. Both will precipitate at the same time E. Neither both are soluble
Gases
15. 5.50 grams of gas A and 5.50 grams of gas B are sealed in a rigid container at a constant temperature. The total pressure of the system is 9.00 atm. Which of the following about the partial pressure of gas B is correct? (#23) B
A. The partial pressure of gas B is equal to ½ the total pressure.
B. In addition to the information provided, one needs to know the relative molecular mass of B in order to determine the partial pressure of gas B.
C. In addition to the information provided, one needs to know the total volume of the container in order to calculate the partial pressure of gas B.
D. In addition to the information provided, one needs to know the temperature of the gas mixture in order to calculate the partial pressure of gas B.
E. In addition to the information provided, one needs to know the average distance traveled between molecular collisions.
16. The density of an unknown gas is 4.00 g/L at 4.00 atm pressure and 127 ºC. What is the molecular weight of this gas? (#26) B
A. 11.8 g•mol-1
B. 32.8 g•mol-1
C. 88.0 g•mol-1
D. 94.1 g•mol-1
E. 138 g•mol-1
17. A sample of neon has a volume of 250. cm3 at 2.00 atm of pressure. At constant temperature, what
would the pressure have to be in order for the gas to have a volume of 5.00 x 102 cm3? (#24) A
A. 1.00 atm B. 3.33 atm C. 15.7 atm D. 21.5 atm E. 43.0 atm
18. Which gas will diffuse twice as fast as SO2 (MW = 64)? (#27) B
A. He (MW = 4) B. CH4 (MW = 16)
C. O2 (MW = 32)
D. HI (MW = 128)
E. None of the above. All gases at the same temperature diffuse at the same rate.
1. Alkenes are hydrocarbons with the general formula, CnH2n. If a 0.420 g sample of any alkene is combusted in excess oxygen, how many moles of water will form? (#75) E
A. 0.0600
B. 0.450 C. 0.015 D. 0.300
E. 0.0300
O ||
HO – C – CH2 – CH3
2. The above compound would be classified as (#74) D A. An aldehyde
B. A ketone C. An ester
Free Response
Bonding
1. The species represented below all have the same number of chlorine atoms attached to the central atom.
GeCl4 SeCl4 ICl4- ICl4+
A. Draw the Lewis structure (electron-dot diagram) of each of the four species. Show all valence electrons in your structures. (1pt per structure = 4pts)
B. On the basis of the Lewis structures drawn in part (A), answer the following questions about the particular species indicated.
i. What is the Cl – Ge – Cl bond angle in GeCl4? (1pt)
109.5º
ii. Is SeCl4 polar? Explain (1 pt)
Yes. The SeCl4 molecule is polar because the lone pair of nonbonding electrons in
the valence shell of the selenium atom interacts with the bonding pairs of electrons, causing a spatial asymmetry of the dipole moments of the polar Se-Cl bonds. The result is a SeCl4 molecule with a net dipole moment.
iii. What is the hybridization of the I atom in ICl4-? (1pt)
sp3d2 or d2sp3
iv. What is the geometric shape formed by the atoms in ICl4+? (1pt)
See-saw (or distorted tetrahedral or disphenoidal)
Nuclear Chem
2. The carbon isotope of mass 12 is stable. The carbon isotopes of mass 11 and mass 14 are unstable. However, the type of radioactivity decay is different for these two isotopes. Carbon–12 is not produced in either case. (a) Identify a type of decay expected for carbon–11 and write the balanced nuclear reaction for that decay
pro-cess.
(b) Identify the type of decay expected for carbon–14 and write the balanced nuclear reaction for that decay process.
(c) Gamma rays are observed during the radioactive decay of carbon–11. Why is it unnecessary to include the gamma rays in the radioactive decay equation of (a)?
Answers:
(a) Positron decay: 116C115B10 OR Electron capture: 116C10e115B
(b) Beta decay: 146C147N10
Gases
3. A rigid 5.00 L cylinder contains 24.5 g of N2(g) and 28.0 g of O2(g)
A. Calculate the total pressure, in atm, of the gas mixture in the cylinder at 298 K.
24.5 g N2 = 0.875 mol N2
28.0 g O2 = 0.875 mol O2
P = = = 8.56 atm
B. The temperature of the gas mixture in the cylinder is decreased to 280 K. Calculate each of
the following.
i. The mole fraction of N2(g) in the cylinder.
= 0.500 mole fraction N2
ii. The partial pressure, in atm, of N2(g) in the cylinder.
= 8.05 atm mole fraction = 8.05 atm 0.500
= 4.02 atm N2
C. If the cylinder develops a pinhole-sized leak and some of the gaseous mixture escapes,
would the ratio in the cylinder increase, decrease, or remain the same? Justify your answer.
