Semester 1 Study Guide Multiple Choice
energy of two isolated atoms
0 J
Which pair of elements is likely to produce a nearly nonpolar covalent bond? (A) Li and Rb (B) Mg and O (C) N and F (D) Te and I
D
1 atm
760 mmHg, 101.3 kPa, 760 torr
A 10.00-g piece of metal is submerged in a graduated cylinder initially containing 20.00 mL of water. With the metal in the cylinder, the level of the water is recorded as 21.40 mL. Determine the identity of the metal. (A) aluminum (density = 2.70 g/mL) (B) zinc (density = 7.13 g/mL) (C) silver (density = 10.49 g/mL) (D) gold (density = 19.32 g/mL)
B
In which of the following electron transitions for a hydrogen atom does the light emitted have the longest wavelength? (A) n = 5 to n = 2 (B) n = 4 to n = 3 (C) n = 3 to n = 1 (D) n = 2 to n = 1
B
Which substance below exhibits the weakest IMFs? a. IF3 b. SO2 c. CO2 d. SiO2 e. PH3
C
Which element is considered a covalent/network solid? a) Cr b) O c) Xe d) B e) Na
D
In a molecule in which the central atom exhibits sp^3 hybrid orbitals, the electron pairs are directed toward the corners of a (A) tetrahedron (B) trigonal pyramid (C) trigonal bipyramid (D) square-based pyramid
A
In which of the following groups are the noble gases arranged correctly in order of increasing boiling point? (A) He, Ne, Kr, Xe (B) Ne, He, Kr, Xe (C) Kr, Xe, Ne, He (D) Xe, Kr, Ne, He Hint: mass #
A
In which one of the following will dipole-dipole attractions play the most significant role as the intermolecular attraction? a) HCl b) NaCl c) Kr d) H2O e) NH3
A
Which of the following statements describes a substance above its critical point? a) the substance can be liquefied b) the vapor and liquid phase become indistinguishable c) the substance experiences no intermolecular interactions d) there is a distinct phase boundary between the liquid and vapor e) all of the above
B
A graduated cylinder contains multiple different liquid layers. Very small samples are taken from the liquids at various heights and tested for density, viscosity, and boiling point. The data are listed below. mL Mark Density (g/mol) Viscosity (Pa • s) Boiling Point (degrees C) 1000 0.83 0.72 242.4 900 0.83 0.71 242.3 800 1.07 0.93 99.7 700 1.08 0.92 99.8 600 1.08 0.93 99.7 500 2.05 1.86 153.5 400 2.06 1.87 153.5 300 2.05 1.85 153.6 200 2.04 1.86 153.6 100 2.05 1.86 153.5 How many different liquids are present in the graduated cylinder? (A) 1 (B) 2 (C) 3 (D) 4
C
An element X has the ground-state valence electron configuration of ns^2 np^5. The formula for the compound composed of element X and nitrogen is most likely (A) NX (B) NX2 (C) NX3 (D) NX5
C
Which response contains all of the characteristics that should apply to BF3? 1. trigonal planar 2. one unshared pair of electrons on B 3. sp^2 hybridized boron atom 4. polar molecule 5. polar bonds a) 2, 4, and 5 b) 1, 3, and 4 c) 1, 2, and 3 d) 1, 3, and 5 e) 3, 4, and 5
D
Which type of solid generally has the highest melting point? a) metallic b) ionic c) molecular d) network
D
With which type of substances do London dispersion forces play the most significant role? a) polar molecules b) metals c) ionic compounds d) non-polar molecules e) network compounds
D
Ion Ionic Radius (pm) Zn^2+ 74 Ca^2+ 100 Ba^2+ 135 Based on the data in the table above, which of the following correctly predicts the relative strength of the attraction of Zn^2+, Ca^2+, and Ba^2+ ions to water molecules in a solution, from strongest to weakest, and provides the correct reason? (A) Zn^2+ > Ca^2+ > Ba^2+ because the smaller ions have a stronger coulombic attraction to water (B) Zn^2+ > Ca^2+ > Ba^2+ because the smaller ions are more electronegative (C) Ba^2+ > Ca^2+ > Zn^2+ because the larger ions are more polarizable (D) Ba^2+ > Ca^2+ > Zn^2+ because the larger ions are less electronegative
A
NaF MgO Boiling Point (degrees C) 1695 3600 Ionic Radius (pm) Na^+ Mg^2+ F^- Cl^- O^2- 76 72 133 181 140 Based on the data in the tables above, which of the following statements provides the best prediction for the boiling point of NaCl? (A) NaCl will have a lower boiling point than NaF because the coulombic attractions are weaker in NaCl than in NaF. (B) NaCl will have a boiling point between that of NaF and MgO because the covalent character of the bonds in NaCl is intermediate between that of MgO and NaF. (C) NaCl will have a higher boiling point than MgO because the ions are spaced farther apart in NaCl. (D) NaCl will have a higher boiling point than MgO because the energy required to transfer electrons from the anion to the cation is larger in NaCl than in MgO.
A
Silicon crystals are semiconductors. Which of the following is a correct reason for the increase in the conductivity of Si crystals when a small fraction of Si atoms are replaced with those of a different element? (A) P atoms introduce additional mobile negative charges. (B) P atoms introduce additional mobile positive charges. (C) Ge atoms have more electrons than Si atoms have. (D) Ge atoms are much smaller than Si atoms.
A
The heat of sublimation of a compound equals a) heat of fusion plus heat of vaporization b) heat of ionization plus heat of crystallization c) heat of vaporization minus heat of fusion d) heat of vaporization plus heat of crystallization e) heat of crystallization plus heat of vaporization
A
The reactivity of the alkali metals increases going down the group. Which is the correct explanation for this trend? (A) The ionization energy decreases as you move down the group, thus it requires less energy to remove the valence electron and results in greater reactivity. (B) The greater nuclear charge as you move down the group results in a greater ability to attract electrons to the atom, thus making them more reactive. (C) As you move down the group, the nucleus's stability decreases, thus causing an increase in the number of radioactive isotopes, hence an increase in the reactivity of the alkali metals. (D) The greater mass as you move down the group causes an increase in the kinetic energy for any given molecular velocity. The increase in kinetic energy accounts for the increase in reactivity.
A
A 100-mL graduated cylinder is filled with 100 mL of water. A few drops of food coloring are added to the top of the water, without mixing. Initially, the top of the graduated cylinder appears to be very dark, while the bottom remains clear and colorless. After 5 minutes the liquid in the graduated cylinder appears to be uniformly colored. Classify the contents in the graduated cylinder before any food coloring is added. (A) element (B) compound (C) heterogeneous mixture (D) homogeneous mixture
B
A correct representation of an ionic solid could be described as having (A) mobile valence electrons shared between positive metal ions (B) positive and negative ions in fixed positions in a framework (C) electrons and positive metal ions in fixed positions in a framework (D) metallic and nonmetallic atoms bonded covalently in a three-dimensional pattern
B
A sample of an unknown material consists of positive ions surrounded by delocalized valence electrons. Which properties are likely for this material? (A) poor conductor of electricity, brittle, volatile (B) good conductor of electricity, easily deformed, nonvolatile (C) poor conductor of electricity, easily deformed, volatile (D) good conductor of electricity, brittle, nonvolatile
B
Element Atomic Radius First Ionization Energy Calcium 194 pm 590 kJ/mol Potassium 一 一 Based on the periodic trends and the data in the table above, which of the following are the most probable values of the atomic radius and the first ionization energy for potassium, respectively? (A) 242 pm, 633 kJ/mol (B) 242 pm, 419 kJ/mol (C) 120 pm, 633 kJ/mol (D) 120 pm, 419 kJ/mol
B
In solid hydrogen fluoride, there are two different distances between H atoms and F atoms. Which of the following best accounts for the two different distances? (A) Accommodation of the necessary bond angles in the formation of the solid (B) Difference in strength between covalent bonds and intermolecular attractions (C) Different isotopes of fluorine present in the samples (D) Uneven repulsions among nonbonding electron pairs
B
Which of the following is ionic and contains both sigma and pi bonds? (A) NO2 (B) KCN (C) C2H4 (D) NaOH
B
Which pair of elements is likely to produce a highly polar covalent bond? (A) Mg and O (B) Li and F (C) O and F (D) C and F
D
Determine 🔺H for the reaction of methane with oxygen. CH4(g) + 2O2(g) ➡️ 3H2O(l) + 2CO2(g) Bond Bond Energy (kJ/mol) C-H 400. O=O 500. C=O 800. O-H 470. (A) -3420 kJ (B) -880 kJ (C) -430 kJ (D) -370 kJ
A
room temperature
20-25 degrees C
Zn(s) is used to reduce other compounds in chemical reactions. If a chemist needs a substance that is more effective in its reducing ability, which of the following species would be the best choice? (A) Na (B) H^+ (C) K^+ (D) Cl^-
A
In which of the footling is the actual compound a resonance hybrid of Lewis structures? a) NO2 b) H2O c) O3 d) CCl4 e) none of these
A and C
What is the hybridization of the oxygen atoms in CH3OH and CO2, respectively? a) sp^3, sp^3 b) sp^3, sp^2 c) sp^2, sp^3 d) sp^2, sp^2 e) sp^3, sp
B
What is the shape of BrI3? a) square planar b) T-shaped c) distorted tetrahedral d) pyramidal e) bent
B
Which diagram shows an excited state? (A) 1s ⬆️ (B) 1s 2s ⬆️ ⬆️ (C) 1s 2s 2p ⬆️⬇️ ⬆️⬇️ ⬆️⬆️⏹ (D) 1s 2s 2p ⬆️⬇️ ⬆️⬇️ ⬆️⬇️⬆️⬇️⬆️⬇️
B
All of the following species contain two pi-bonds EXCEPT a) SCN^- b) CO c) H2CCO d) OCS e) NO^-
E
During the condensing of a liquid, the kinetic energy ___________ and the potential energy ___________. a) stays the same, decreases b) increases, decreases c) increases, increases d) decreases, stays the same e) stays the same, decreases
E
Surface tension in a liquid is due to the fact that a) surface molecules are pulled toward the interior b) liquids tend toward lowest energy c) PE is increased for molecules at the surface d) interior molecules are attracted in all directions e) all of the above
E
The heat of vaporization of H2S, at its boiling point (-61 C) is 18.8 kJ/mol. What mass of H2S can be vaporized (at its boiling point) with 100 kJ of energy? a) 100 x 61/18.8 b) 34.1 x 18.8/100 c) 61 x 18.8 x 100 x 34.1 d) 18.8 x 61/34.1 e) 100 x 34.1/18.8
E
Which hybridization is associated with a steric number of 3? a) sp b) sp^2 c) sp^3 d) sp^3 d e) sp^3 d^2
b
The table below shows the first eight ionization energies for four random elements from second and third periods of the periodic table. Based on these data, which elements would most likely have similar chemical properties? Ionization Elements Energy (kJ/mol) W X Y Z First 1,314 1,000 578 496 Second 3,388 2,252 1,817 4,562 Third 5,301 3,357 2,745 6,910 Fourth 7,469 4,556 11,577 9,543 Fifth 10,990 7,004 14,842 13,354 Sixth 13,327 8,496 18,379 16,613 Seventh 71,330 27,107 23,326 20,117 Eighth 84,078 31,719 27,465 25,496 (A) W and X (B) W and Y (C) X and Z (D) Y and Z
A
The vapor pressure of a liquid increases with an increase of temperature. Which of the following best explains this increase? a) The average kinetic energy of molecules is greater, thus more molecules can enter the gaseous state. b) The number of gaseous molecules above the liquid remains constant but these molecules have greater average kinetic energy. c) the faster moving molecules in the liquid exert a greater pressure. d) All of the molecules have greater kinetic energies. e) The intermolecular forces between the molecules becomes less at higher temperatures.
A
When cotton balls are placed in the ends of a tube at the same time, the gases diffuse from each end and meet somewhere in between, where they react to form a white solid. Which of the following combinations will produce a solid closest to the center of the tube? (A) HCl and CH3NH2 (B) HCl and NH3 (C) HBr and CH3NH2 (D) HBr and NH3
A
When placed in order of increasing atomic radius, what is the correct order for the elements Al, Ca, and Mg? (A) Al, Mg, Ca (B) Mg, Al, Ca (C) Ca, Al, Mg (D) Ca, Mg, Al
A
Which ion listed has no resonance structures and exactly two pi bonds? (A) CN^- (B) O3^- (C) OH^- (D) CO3^2-
A
Which of the following best explains the difference in the melting points of MgO (2852 C) and NaF (1819 C)? (A) There are greater Coulombic attractions in MgO due to the greater charges on the ions. (B) Na is above Mg on the activity series of metals. (C) F is more electronegative than O. (D) Na is an alkali metal, and Mg is an alkaline earth metal. Alkali metals are more reactive than the alkaline earth metals.
A
Which of the following combinations of elements is likely to produce an ionic bond? (A) Li and Cl (B) Li and Rb (C) N and S (D) N and O
A
Which of the following compounds shows an abnormal boiling point due to hydrogen bonding? a) CH3NH2 b) CH3OCH3 c) CH3SH d) CH3Cl e) HCl
A
Which of the following will change the equilibrium vapor pressure of a liquid? I. Heat up or cool down the liquid II. Increase the Volume of the container III. Change the pressure above the liquid a) I only b) I and II only c) I, II, and III d) I and III only e) II and III only
A
Which of the following would be expected to have the highest heat of vaporization? a) H2O b) NH3 c) HF d) all three are the same
A
Which of these correctly matches the molecular compound with the most important force between molecules or the same substance? (A) ammonia: hydrogen bonding (B) hydrogen cyanide: ionic bonding (C) propane (C3H8): dipole-dipole attractions (D) hydrogen sulfide: London dispersion forces
A
Which of these statements provides an accurate comparison of the general properties of solids and liquids? (A) In a solid, particles are slightly closer together, have greater interparticle attractions, and have lower particle motion compared with a liquid. (B) In a solid, particles are slightly further apart, have weaker interparticle attractions, and have lower particle motion compared with a liquid. (C) In a solid, particles are slightly closer together, have weaker interparticle attractions, and have greater particle motion compared with a liquid. (D) In a solid, particles are slightly further apart, have weaker interparticle attractions, and have greater particle motion compared with a liquid.
A
Which statement correctly describes the changes occurring in the two equations shown below? Equation I: H2O(s) ➡️ H2O(l) Equation II: 2H2O(l) ➡️ 2H2(g) + O2(g) (A) Equation I represents a physical change because only intermolecular bonds are broken, whereas Equation II represents a chemical change because intramolecular bonds are broken. (B) Equation I represents a physical change because only intramolecular bonds are broken, whereas Equation II represents a chemical change because intermolecular bonds are broken. (C) Equation I represents a chemical change because only intermolecular bonds are broken, whereas Equation II represents a physical change because intramolecular bonds are broken. (D) Equation I represents a chemical change because only intramolecular bonds are broken, whereas Equation II represents a physical change because intermolecular bonds are broken.
A
The melting points of the compounds LiF, NaCl, KBr, and CsI exhibit the following trend: Melting point order: LiF > NaCl > KBr > CSI Which of the following correctly explains this trend? (A) The increasing molar mass requires more energy to melt the substances. (B) The greater radii of the larger ions results in smaller lattice energies, leading to lower melting points. (C) Reactivity increases as you increase the atomic number in the alkali metals. The more reactive, the easier it is to lose electrons, hence a lower melting point. (D) The melting point is directly proportional to the electronegative value for the halogen ions in the compound; there is more attraction for the electrons in the chemical bonds.
B
The normal boiling point of a liquid a) is 100 C at 1 atm pressure. b) is the temperature at which the vapor pressure is 1 atm. c) is the temperature at which liquid and vapor are in equilibrium, d) is the temperature at which the vapor pressure equals the external pressure. e) is the temperature at which there is a continuous formation of gaseous bubbles in the liquid.
B
The table shows the first ionization energies of element X in kJ/mol. First ionization energy: 738 Second ionization energy: 1450 Third ionization energy: 7730 What is the most likely formula of the compound between element X and Y, where Y is a halogen? (A) XY (B) XY2 (C) XY3 (D) X3Y
B
Use the following information to calculate the H-Cl bond energy. Reaction 🔺H (kJ) H2(g) + Cl2(g)➡️2HCl(g) -180 H2(g)➡️2H(g) 430 Cl2(g)➡️2Cl(g) 240 (A) 325 kJ (B) 425 kJ (C) 490 kJ (D) 950 kJ
B
What hybridization is predicted for phosphorus in the PCl3 molecule? a) sp^2 b) sp^3 c) sp d) sp^3 d^2
B
What is the electron configuration for Zn^2+? (A) 1s^2 2s^2 2p^6 3s^2 3p^6 3d^8 (B) 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 (C) 1s^2 2s^2 2p^6 3s^2 3p^6 3d^8 4s^2 (D) 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2
B
Which of the following electron configurations shows the ground state of an ion of a halogen? (A) 1s^2 2s^2 2p^5 3s^2 3p^5 (B) 1s^2 2s^2 2p^6 3s^2 3p^6 (C) 1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 (D) 1s^2 2s^2 2p^6 2d^10 3s^2 3p^6
B
Which of the following has the lowest boiling point? a) H2O b) H2S c) H2Se d) H2Te e) NH3 Hint: atomic #, think about boiling point for water and hydrogen bonding
B
Which one of the following is linked with the correct intermolecular force of attraction? a) NH3 (dipole-dipole) b) AlH3 (London dispersion forces) c) H2 (hydrogen bonding) d) C2H4 (covalent bonding) e) HCl (ionic)
B
A 100-mL graduated cylinder is filled with 100 mL of water. A few drops of food coloring are added to the top of the water, without mixing. Initially, the top of the graduated cylinder appears to be very dark, while the bottom remains clear and colorless. After 5 minutes the liquid in the graduated cylinder appears to be uniformly colored. Classify the contents in the graduated cylinder just after the food coloring is added. (A) element (B) compound (C) heterogeneous mixture (D) homogeneous mixture
C
Compound Molecular Formula Molar Mass (g/mol) Boiling Point (degrees C) Nonane C9H20 128 151 2,3,4-trifluoropentane C5H9F3 126 89 Nonane and 2,3,4-trifluoropentane have almost identical molar masses, but nonane has a significantly higher boiling point. Which of the following statements best helps explain this observation? (A) The C-F bond is easier to break than the C-H bond. (B) The C-F bond is more polar than the C-H bond. (C) The carbon chains are longer in nonane than they are in 2,3,4-trifluoropentane. (D)The carbon chains are farther apart in a sample of nonane than they are in 2,3,4-trifluoropentane.
C
Which of the following favors formation of an ionic compound? a) low ionization energy for metal b) high electron affinity for non metal c) high lattice energy d) all of a-c above e) none of a-c above
D
Element Metallic Radius (pm) Melting Point (degrees C) Common Oxidation State Au 144 1064 1+, 3+ Cu 128 1085 1+, 2+ Ag 144 961 1+ To make Au stronger and harder, it is often alloyed with other metals, such as Cu and Ag. Consider two alloys, one of Au and Cu and one of Au and Ag, each with the same mole fraction of Au. If the Au/Cu alloy is harder than the Au/Ag alloy, then which of the following is the best explanation based on the information in the table above? (A) Cu has two common oxidation states, but Ag has only one. (B) Cu has a higher melting point than Au has, but Ag has a lower melting point than Au has. (C) Cu atoms are smaller than Ag atoms, thus they interfere more with the displacement of atoms in the alloy. (D) Cu atoms are less polarizable than are Au or Ag atoms, thus Cu has weaker interparticle forces.
C
How many electrons are shown in the Lewis structure of perchlorate ion, ClO4^-? a) 30 b) 31 c) 32 d) 50 e) 51
C
How many sigma and pi electrons pairs are in a carbon dioxide molecule? a) four sigma and zero pi b) three sigma and two pi c) two sigma and two pi d) two sigma and four pi e) one sigma and three pi
C
In a molecule in which the central atom exhibits sp^2 hybrid orbitals, the arrangement of electron pairs is (A) linear (B) tetrahedral (C) trigonal planar (D) trigonal bipyramidal
C
In some compounds the hydrogen atom is covalently bonded to one atom and simultaneously attracted to another atom in another molecule by an electrostatic interaction. This interaction can occur when hydrogen is bonded to a) Cl b) Si c) N d) C e) Br
C
Ionic solids are not able to conduct electricity in the solid phase but are able to conduct electricity when dissolved in water. This can best be explained by the fact that the ions (A) release free electrons when dissolved in water (B) form molecules that conduct electricity when dissolved in water (C) are in fixed positions in the solid phase, whereas they are free to move in solution (D) are not able to conduct electricity themselves, but water molecules can conduct electricity
C
Of the most common ions of the third period elements Mg, Al, P, and S, which is the largest? (A) Mg (B) Al (C) P (D) S Hint: because of nuclear charge (but if not, size increases down a group)
C
Substance Equilibrium Vapor Pressure at 20 degrees C (torr) C6H6(l) 75 C2H5OH(l) 44 CH3OH(l) 92 C2H6O2(l) 0.06 Based on the data in the table above, which of the following liquid substances has the weakest intermolecular forces? (A) C6H6(l) (B) C2H5OH(l) (C) CH3OH(l) (D) C2H6O2(l)
C
The boiling points of hydrogen chloride and hydrogen bromide are given in the table below. Based on periodicity and intermolecular forces, which of the other two hydrogen halides would have a boiling point that is higher than that of HBr? Compound HCl HBr HI HF Boiling Point -85 C -66 C ? ? (A) HI only (B) HF only (C) HI and HF (D) Neither HI nor HF
C
The elements I and Te have similar average atomic masses. A sample that was believed to be a mixture of I and Te was run through a mass spectrometer. All of the following statements are true. Which one would be the best basis for concluding that the sample was pure Te? (A) Te forms ions with a -2 charge, whereas I forms ions with a -1 charge. (B) Te is more abundant than I in the universe. (C) I consists of only one naturally occurring isotope with 74 neutrons, whereas Te has more than one isotope. (D) I has a higher first ionization energy than Te does.
C
The expected electron configuration for copper should be [Ar]4s^2 3d^9. However, copper's electron configuration is [Ar]4s^1 3d^10. Which of the following would provide experimental evidence of copper's exception to the normal electron configuration? (A) The mass spectrum of copper shows the different isotopes of copper. (B) Copper ions in solution have color, which indicates that there are unpaired d orbital electrons. (C) The photoelectron spectroscopy spectrum for copper shows the relative number of electrons in each orbit. (D) Copper has the ability to form cations of plus one and plus two, whereas the other transition elements generally form cations of plus two and plus three.
C
The first ionization energy of magnesium is 738 kJ/mol. A good estimate for the second ionization energy of magnesium is (A) 370 kJ/mol (B) 735 kJ/mol (C) 1450 kJ/mol (D) 6900 kJ/mol
C
The molecule BrF3 has a steric number of ________ on the central atom? a) 3 b) 4 c) 5 d) 6 Hint: electron domains
C
The molecule BrF3 has how many lone pairs of electrons on the central atom? a) 0 b) 1 c) 2 d) 3
C
What is the best explanation for the decrease in first ionization energy moving from N to O? (A) The oxygen atom is smaller, thus making it easier to remove the electrons compared with N. (B) The electrons in N are being removed from a half-full subshell, which is more stable than the partially filled subshell in O. (C) The electrons in N occupy the 2p orbitals singularly, whereas the electrons in one of the 2p orbitals of O are paired, thus increasing the electron-electron repulsions. (D) Moving from N to O, there are more protons in the nucleus, thus increasing the effective nuclear charge (Z*eff), causing a greater amount of attraction for the valence electrons and making it harder to remove the electrons.
C
When each of the following is heated to 50 degrees C and the moderate is held constant for 5 minutes, which one undergoes only a physical change? (A) egg (B) steak (C) ice cream (D) cake batter
C
Which of the following best describes BF3 and NF3? (Note: Geometry refers to the electron pair arrangement, and shape refers to the atom arrangement.) (A) They have the same geometry and different shapes. (B) They have the same geometry and the same shape. (C) They have different geometry and different shapes. (D) They have different geometry and the same shape.
C
Which of the following electron configurations shows a violation of Hund's rule? (A) 1s ⬆️ (B) 1s 2s ⬆️⬇️ ⬆️ (C) 1s 2s 2p ⬆️⬇️ ⬆️⬇️ ⬆️⬇️⏹⏹ (D) 1s 2s 2p ⬆️⬇️ ⬆️⬇️ ⬆️⬇️⬆️⬇️⬆️⬇️
C
Which of the following indicates very strong intermolecular forces of attraction in a liquid? a) A very low boiling point. b) A very low critical temperature. c) A very low heat of vaporization. d) A very low vapor pressure. e) A very low surface tension.
D
Which of the following is the best explanation for the difference in the boiling points of liquid Br2 and I2, which are 59 degrees C and 184 degrees C, respectively? (A) Solid iodine is a network covalent solid, whereas solid bromine is a molecular solid. (B) The covalent bonds in I2 molecules are weaker than those in Br2 molecules. (C) I2 molecules have electron clouds that are more polarizable than those of Br2 molecules, thus London dispersion forces are stronger in liquid I2. (D) Bromine has a greater electronegativity than iodine, thus there are stronger dipole-dipole forces in liquid bromine than in liquid iodine.
C
Which of the following molecular shapes has six atoms joined to a central atom? a) linear b) tetrahedral c) octahedral d) trigonal bipyramid e) planar triangular
C
Which one of the following compounds has intermolecular forces different than the others? a) quartz, SiO2 b) C (diamond) c) carbon dioxide, CO2 d) C (graphite) e) silicon carbide, SiC
C
Which pair of elements is likely to produce an ionic bond? (A) O and F (B) S and N (C) Li and Cl (D) Ca and Ba
C
Which of the following is the reason that ionization energy generally increases from left to right across the first period of the periodic table? (A) As the atomic number increases, the electrons are harder to remove. (B) Ionization energy increases as the atomic number increases in a period. (C) As the atomic number increases, more electrons are added to the atoms, thus increasing the electron-electron repulsions. (D) As the atomic number increases, more protons in the nucleus cause an increase in the effective nuclear charge, making it harder to remove the electrons.
D
Which one of the following substances exhibits the strongest intermolecular forces of attraction? a) CH4 b) C2H6 c) C3H8 d) CH3OH e) CH3Cl
D
A 10-lane Olympic-sized swimming pool contains 2.5 x 10^6 kg of water. If the water is at 0°C, how many kilojoules of energy must be removed to freeze the water in this pool? ΔHfus for H2O = 334 J/g (A) 7.5 x 10^3 kJ (B) 8.4 x 10^5 kJ (C) 7.5 x 10^6 kJ (D) 8.4 x 10^8 kJ
D
A 100-mL graduated cylinder is filled with 100 mL of water. A few drops of food coloring are added to the top of the water, without mixing. Initially, the top of the graduated cylinder appears to be very dark, while the bottom remains clear and colorless. After 5 minutes the liquid in the graduated cylinder appears to be uniformly colored. Classify the contents in the graduated cylinder after the 5 minutes has elapsed. (A) element (B) compound (C) heterogeneous mixture (D) homogeneous mixture
D
A double bond contains _______ sigma bond(s) and ______ pi bond(s). a) 0, 2 b) 1, 2 c) 2, 0 d) 1, 1
D
As the bond order of a carbon-carbon bond increases, which one of the following decreases? a) # of electrons between the carbon atoms b) vibrational frequency of bond vibrations c) bond energy (bond strength) d) bond length
D
For which substance would you predict the highest heat of vaporization? a) F2 b) H2O c) HF d) NaCl e) Br2
D
How many of the following molecules have two pi bonds? HCN, C2H2, CO2, OCl2 (A) 0 (B) 1 (C) 2 (D) 3
D
How much energy does it require to melt 25.0 g benzene, C6H6? The heat of fusion of benzene is 2.37 kJ/mol. [molar mass = 78.0 g/mol) a) 8.25 kJ b) 59.3 kJ c) 4625 kJ d) 0.759 kJ e) none of these
D
Of HCO3^-, CO3^2-, CO2, and CO, which one has the shortest C-O bond length? (A) HCO3^- (B) CO3^2- (C) CO2 (D) CO
D
Several of Jupiter's moons are believed to have a liquid layer, possibly water, below their icy surfaces. NASA and the European Space Agency are planning several interplanetary probes that will visit the moons of Jupiter. It has been suggested that a probe could land on one of the moons and drill through the surface of ice to the liquid layer. The probe would then sample the liquid at five different depths. Why will the probe test the liquid at five different depths? (A) to determine whether the liquid layer is water (B) to determine whether the liquid layer could support life (C) to determine the chemical composition of the liquid layer (D) to determine whether the liquid layer is a homogenous solution or heterogenous mixture
D
Silicon dioxide, SiO2, is a covalent network solid with each silicon atom bonded to four oxygen atoms, forming a large network of SiO4 tetrahedra of great strength. Which of these other compounds would you predict to have similar properties? (A) MgO (B) CO2 (C) SO2 (D) GeO2
D
The compounds Br2 and ICl have almost identical molecular weights, yet ICl boils at 97 C and Br2 boils at 59 C. The best explanation for the difference is a) ICl is an ionic compound and Br2 is covalent. b) ICl is a nonpolar molecule and Br2 is polar. c) ICl has a longer bind than that in Br2. d) ICl has a measurable dipole moment (is polar) and Br2 does not (is nonpolar). e) ICl has a stronger bond than that in Br2.
D
The molecular geometry and polarity of CO2 and SO2 are (A) the same because the molecular formulas are similar (B) the same because C and S have similar electronegativity values (C) different because the lone pair of electrons on the S atom make it the negative end of a dipole (D) different because S has a greater number of electron domains (regions of electron density) surrounding it than C has
D
The photoelectron spectra above show the energy required to remove a 1s electron from a nitrogen atom and from an oxygen atom. Which of the following statements best accounts for the peak in the upper spectrum being to the right of the peak in the lower spectrum? (A) Nitrogen atoms have a half-filled p subshell. (B) There are more electron-electron repulsions in oxygen atoms than in nitrogen atoms. (C) Electrons in the p subshell of oxygen atoms provide more shielding than electrons in the p subshell of nitrogen atoms. (D) Nitrogen atoms have a smaller nuclear charge than oxygen atoms.
D
What's the best explanation for the decrease in first ionization energy moving from Be to B? (A) Moving from Be to B, more electrons are added to the atoms, thus increasing the electron-electron repulsions. (B) Moving from Be to B more protons in the nucleus attract the valence electrons, making it harder to remove the electrons. (C) The electrons in Be are being removed from a full subshell, which is more stable than the half-filled subshell in B. (D) The electrons in Be are located in the 2s subshell, which is closer to the nucleus and thus harder to remove than the 2p electrons in B.
D
When placed in order of increasing ionization energy, what is the correct order for the species O, O^+, and O^-? (A) O, O^+, O^- (B) O, O^-, O^+ (C) O^+, O, O^- (D) O^-, O, O^+
D
Which best explains why an aluminum can may be crushed without it breaking into pieces? (A) Aluminum has ionic bonds that are not easily broken. (B) aluminum has covalent bonds that are not easily broken. (C) Aluminum has localized valence electrons with directional bonding. (D) Aluminum has delocalized valence electrons with nondirectional bonding.
D
Which of the following correctly ranks the following species from smallest to largest ionic radius? (A) Cl^-, S^2+, K^+, Ca^2+ (B) K^+, Ca^2+, Cl^-, S^2- (C) S^2-, Cl^-, K^+, Ca^2+ (D) Ca^2+, K^+, Cl^-, S^2-
D
What process corresponds to lattice energy? 1. Li (s) ➡️ Li (g) 2. 1/2F2 (g) ➡️ F (g) 3. Li (g) ➡️ Li^+ (g) 4. F (g) ➡️ F^- (g) 5. F^- (g) ➡️ LiF (s) a) 1 b) 2 c) 3 d) 4 e) 5
E
What type of solid(s) can contain covalent bonds? a) molecular b) metallic c) ionic d) network e) all but "b"
E
Which molecular shape has bond angles which are not all the same? a) linear b) tetrahedral c) octahedral d) planar triangular e) trigonal bipyramid
E
Which of the atoms below is least likely to violate the octet rule? a) Be b) P c) S d) B e) F
E
Which of the following bonds is most polar? a) N - Cl b) C - N c) S - S d) Br - Br e) S - O
E
Which one of the following as solids has a crystal structure containing discrete (separate) molecules? a) potassium b) glass c) quartz d) carborundum, SiC e) hydrogen
E