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Chemistry
Q:
The weight percent of concentrated HClO4(aq) is 70.5% and its density is 1.67 g/mL. What is the molarity of concentrated HClO4?
A.4.20 M
B.7.18 M
C.11.7 M
D.14.2 M
E.39.7 M
Q:
What is the weight percent of acetic acid in 7.23 m CH3CO2H(aq)?
A.0.718%
B.7.17%
C.11.5%
D.30.3%
E.42.4%
Q:
What is the mole fraction of water in a solution that is 33.3% by weight ethylene glycol? The molar mass of ethylene glycol, HOCH2CH2OH, is 62.07 g/mol.
A.0.127
B.0.290
C.0.368
D.0.667
E.0.873
Q:
What is the mole fraction of calcium chloride in 3.35 m CaCl2(aq)? The molar mass of CaCl2 is 111.0 g/mol and the molar mass of water is 18.02 g/mol.
A.0.000866
B.0.0569
C.0.271
D.37.2
E.59.2
Q:
If the molality of a NaBr(aq) solution is 2.50 m, what is the weight percent of NaBr? The molar mass of NaBr is 102.9 g/mol.
A.20.5%
B.25.0%
C.25.7%
D.34.6%
E.65.4%
Q:
If 77.5 g of ethylene glycol (HOCH2CH2OH) is added to 422.5 g of water, what is the mole fraction of ethylene glycol?
A.0.00296
B.0.0506
C.0.183
D.0.949
E.2.96
Q:
If 26.5 g of methanol (CH3OH) is added to 735 g of water, what is the molality of the methanol?
A.0.0348 m
B.2.03 m
C.1.13 m
D.3.61 m
E.36.1 m
Q:
If 27.9 g LiCl is dissolved in 175 g H2O, what is the weight percent of LiCl in the solution?
A.0.376%
B.6.78%
C.13.8%
D.15.9%
E.19.0%
Q:
What is the definition of molality?
A.moles of solute per kg of solvent
B.grams of solute per kg of solution
C.grams of solute per liter of solution
D.moles of solute per liter of solvent
E.moles of solute per liter of solution
Q:
Which ion, K+ or Ca2+, is expected to have the more negative enthalpy of hydration? Why?
Q:
Above a substance's ________ temperature, it is not possible to compress the substance into the liquid phase. If enough pressure is applied the substance will become a supercritical fluid.
Q:
Sodium chloride crystallizes in a(n) ________ cubic unit cell with chloride ions occupying the lattice points. The sodium ions occupy interstitial regions, with each cation in contact with six chloride ions.
Q:
A salt with a 1:1 ratio of anions to cations may pack in a face-centered cubic unit cell with the anions at the lattice points and the cations occupying one-half of the ________ holes. Zinc sulfide is an example of this structure.
Q:
Point D on the phase diagram is referred to as the ________ point. A.triple
B.normal boiling
C.critical
D.normal freezing
E.divergent
Q:
What process occurs when the temperature of a substance is at Point A increased (at constant pressure) until the substance is at Point B? A.condensation
B.vaporization
C.sublimation
D.melting
E.freezing
Q:
If a pure substance begins at point C on the phase diagram below and the pressure on the substance is increased until point B is reached, what process occurs? A.fusion
B.vaporization
C.condensation
D.sublimation
E.none of these
Q:
Which of the statement concerning the phase diagram is/are CORRECT?
1/ Only the solid phase exists at point A.
2/ At point C, the solid and liquid phases are in equilibrium.
3/ At point D, the critical point, the substance exists as a supercritical fluid. A.1 only
B.2 only
C.3 only
D.1 and 3
E.1, 2, and 3
Q:
The phase diagram for CO2 has a triple point at -56.6 C and 5.19 atm, and a critical point at 31.0 C and 73 atm. The solid and gas phases are in equilibrium at -78.7 C and 1.00 atm. Which of the following statements regarding CO2 is/are CORRECT?1/ Sublimation occurs if the temperature of the solid phase is increased from -79.0 C to 0.0 C at a constant pressure of 2.5 atm.2/ CO2 is a supercritical fluid at 55 C and 75 atm.3/ At pressures greater than its critical pressure (73 atm), CO2 will not exist as a solid at any temperature.A.1 onlyB.2 onlyC.3 onlyD.1 and 2E.1, 2, and 3
Q:
A phase diagram of a pure compound has a triple point at 22.0 C and 32 mm Hg, a normal melting point at 22.8 C, and a normal boiling point at 107 C. Which of the following statements regarding this compound is/are CORRECT?
1/ The density of the liquid is greater than that of the solid.
2/ Sublimation occurs if starting with a solid at a constant temperature of 25 C the pressure is decreased until a phase change occurs.
3/ Condensation occurs if the temperature is decreased from 122 C to 75 C at a constant pressure of 1.00 atm.
A.1 only
B.2 only
C.3 only
D.1 and 2
E.1, 2, and 3
Q:
Which process requires the greatest endothermic change in enthalpy for water?
A.freezing
B.condensation
C.sublimation
D.melting
E.vaporization
Q:
Which two of the following materials are most likely to be amorphous solids: water, nylon, glass, potassium nitrate?
A.water and glass
B.nylon and aspirin
C.water and nylon
D.water and aspirin
E.nylon and glass
Q:
Which of the following is/are physical properties of amorphous solids?
1/ Amorphous solids have well defined melting points.
2/ At the particulate level, amorphous solids do not have long range order.
3/ Polymeric materials never form amorphous solids.
A.1 only
B.2 only
C.3 only
D.1 and 3
E.2 and 3
Q:
Which of the following is NOT a network solid?
A.elemental silicon, Si(s)
B.diamond, C(s)
C.buckminster fullerene, C60(s)
D.silicon dioxide, SiO2(s)
E.aluminum oxide, Al2O3(s)
Q:
Using the thermodynamic data below, and a value of -717 kJ/mole for the lattice enthalpy for KCl, calculate the ionization energy of K.Enthalpy of atomization of K +89 kJ/molEnthalpy of formation of solid KCl -437 kJ/molEnthalpy of formation of Cl(g) +121 kJ/molElectron affinity of Cl(g) -349 kJ/molA.-576 kJ/molB.+141 kJ/molC.+419 kJ/molD.+576 kJ/molE.+597 kJ/mol
Q:
Calculate the lattice energy of NaBr(s), given the following thermochemical equations, where DIE and DEA are ionization energy and electron affinity, respectively.Na(s) Na(g) DfH = +107 kJNa(g) Na+(g) + e- DIE = +496 kJ1/2 Br2(g) Br(g) DfH = +112 kJBr(g) + e- Br-(g) DEA = -325 kJNa(s) + 1/2 Br2(g) NaBr(s) DfH = -361 kJA.-963 kJB.-751 kJC.-290 kJD.+290 kJE.+1403 kJ
Q:
Lattice enthalpy may be calculated using the thermodynamic relationship known as
A.the Clausius-Clapeyron equation.
B.the Born-Haber cycle.
C.the dynamic equilibrium expression.
D.Avogadro's hypothesis.
E.cubic cell enthalpy of formation equation.
Q:
The lattice energy of NaBr is -752 kJ/mol. This energy corresponds to which reaction below?A.Na(s) + 1/2 Br2(g) NaBr(s)B.Na(g) + Br(g) NaBr(s)C.Na(g) + Br(g) NaBr(s)D.Na+(g) + Br-(g) NaBr(s)E.Na+(aq) + Br-(aq) NaBr(s)
Q:
Which of the following statements concerning semiconductors is/are CORRECT?
1/ The conduction of electricity in p-type semiconductors occurs by the movement of electrons in the conduction band.
2/ Doping an intrinsic semiconductor, such as silicon, with a Group 3A element will produce a p-type semiconductor.
3/ An n-type semiconductor uses the movement of positive holes in the valence band to conduct electricity.
A.1 only
B.2 only
C.3 only
D.1 and 2
E.1, 2 and 3
Q:
In metals, there are not enough electrons to fill all of the electronic energy levels. At 0 K, the highest energy level filled is referred to as the ________.
A.valence band
B.conduction band
C.free energy
D.Fermi level
E.band gap
Q:
Which of the following compounds is expected to have the strongest ionic bonds?
A.MgO
B.KBr
C.NaI
D.BaO
E.SrS
Q:
Which of the following compounds is expected to have the strongest ionic bonds?
A.RbI
B.KCl
C.NaBr
D.CsF
E.LiF
Q:
Iron(II) sulfide has a primitive cubic unit cell with sulfide ions at the lattice points. The ionic radii of iron(II) ions and sulfide ions are 88 pm and 184 pm, respectively. What is the density of FeS (in g/cm3)?
A.2.56 g/cm3
B.4.71 g/cm3
C.5.25 g/cm3
D.6.66 g/cm3
E.8.97 g/cm3
Q:
Magnesium sulfide (molar mass 56.37 g/mol) has a face-centered cubic unit cell with magnesium ions in octahedral holes. The ionic radii of magnesium ions and sulfide ions are 79 pm and 184 pm, respectively. What is the density of MgS (in g/cm3)?
A.1.29 g/cm3
B.2.57 g/cm3
C.3.64 g/cm3
D.5.15 g/cm3
E.7.28 g/cm3
Q:
Rubidium iodide (molar mass 212.4 g/mol) has a face-centered cubic unit cell with rubidium ions in octahedral holes. If the radius of iodide ion is 219 pm and the density of RbI is 3.55 g/cm3, what is the radius of the rubidium ion (in pm)?
A.112 pm
B.149 pm
C.181 pm
D.297 pm
E.419 pm
Q:
Calcium sulfide has a face-centered cubic unit cell with calcium ions in octahedral holes. How many ions of each element are contained in each unit cell?
A.1 calcium ions; 1 sulfide ions
B.2 calcium ions; 2 sulfide ions
C.2 calcium ions; 4 sulfide ions
D.4 calcium ions; 2 sulfide ions
E.4 calcium ions; 4 sulfide ions
Q:
If an ionic compound with the formula MX forms a primitive cubic unit cell with the anions (Xn-) at the lattice points, the cations (M2n+) will occupyA.all of the tetrahedral holes in each unit cell.B.half of the tetrahedral holes in each unit cell.C.the cubic hole in the center of the each unit cell.D.the center of each face in each unit cell.E.all of the octahedral holes in each unit cell.
Q:
If an ionic compound with the formula MX2 forms a face-centered cubic unit cell with the cations (M2n+) at the lattice points, the anions (Xn-) will occupyA.all of the tetrahedral holes in each unit cell.B.half of the tetrahedral holes in each unit cell.C.all of the octahedral holes in each unit cell.D.the center of each face in each unit cell.E.the cubic hole in the center of the each unit cell.
Q:
If an ionic solid has a face-centered cubic lattice of anions (Xn-) and all the octahedral holes are occupied by metal cations (Mm+), what is the formula for the compound?
A.M2X
B.MX
C.MX2
D.M2X3
E.M3X2
Q:
Which of the following statements is/are CORRECT? If an ionic compound with the formula MX forms a face-centered cubic unit cell with the anions (Xn-) at the lattice points, the cations (Mn+) may occupy1/ one fourth of the tetrahedral holes in each unit cell.2/ all of the octahedral holes in each unit cell.3/ the center of each face in each unit cell.A.1 onlyB.2 onlyC.3 onlyD.1 and 2E.1, 2, and 3
Q:
Lithium chloride crystallizes in a face-centered cubic unit cell with chloride ions occupying the lattice points and lithium ions occupying octahedral holes. How many chloride ions surround each lithium ion in LiCl?
A.1
B.4
C.6
D.8
E.12
Q:
Cesium bromide crystallizes in a primitive cubic unit cell with bromide ions at the lattice points. The cesium ions occupy cubic holes. How many bromide ions surround each cesium ion in cesium bromide?
A.1
B.2
C.4
D.8
E.12
Q:
Chromium (atomic mass 52.00 g/mol) crystallizes in a body-centered cubic unit cell. If the length of an edge of the unit cell is 289 pm, what is the density (in g/cm3) of chromium?
A.3.58 g/cm3
B.7.15 g/cm3
C.13.7 g/cm3
D.14.3 g/cm3
E.21.3 g/cm3
Q:
The radius of an indium atom is 0.163 nm. If indium crystallizes in a face-centered unit cell, what is the length of an edge of the unit cell?
A.0.188 nm
B.0.231 nm
C.0.326 nm
D.0.376 nm
E.0.461 nm
Q:
Aluminum crystallizes in a face-centered unit cell. If the length of an edge of the unit cell is 404 pm, what is the radius of an aluminum atom (in pm)?
A.101 pm
B.143 pm
C.175 pm
D.202 pm
E.286 pm
Q:
Polonium (atomic mass 209.0 g/mol) crystallizes in a primitive cubic unit cell. If the density of polonium is 9.15 g/cm3, what is the radius of a polonium atom (in pm)?
A.168 pm
B.238 pm
C.336 pm
D.475 pm
E.672 pm
Q:
Niobium crystallizes in a body-centered cubic unit cell. If the radius of a niobium atom is 0.145 nm, what is the length of an edge of the unit cell?
A.0.251 nm
B.0.290 nm
C.0.335 nm
D.0.410 nm
E.0.502 nm
Q:
Potassium crystallizes in a body-centered cubic unit cell. If the length of an edge of the unit cell is 524 pm, what is the atomic radius (in pm) of a potassium atom?
A.151 pm
B.185 pm
C.227 pm
D.262 pm
E.371 pm
Q:
Rhodium (atomic mass 102.9 g/mol) crystallizes in a face-centered cubic unit cell. In addition, rhodium has an atomic radius of 135 pm. What is the density (in g/cm3) of rhodium?
A.1.53 g/cm3
B.6.14 g/cm3
C.17.4 g/cm3
D.12.3 g/cm3
E.27.8 g/cm3
Q:
Nickel has a face-centered cubic cell, and its density is 8.90 g/cm3. What is the radius (in pm) of a nickel atom? (The molar mass of nickel is 58.69 g/mol)
A.62.3 pm
B.88.1 pm
C.125 pm
D.249 pm
E.535 pm
Q:
What is the distance, in atomic radii, along any edge of a body-centered unit cell?
A.
B.2 r
C.4 r
D.
E.r
Q:
What is the distance, in atomic radii, along any edge of a face-centered unit cell?
A.
B.2 r
C.4 r
D.
E.r
Q:
What is the distance, in atomic radii, across a diagonal face of a face-centered unit cell?
A.
B.2 r
C.4 r
D.
E.r
Q:
What is the distance, in atomic radii (r), along any edge of a primitive unit cell?
A.r
B.2 r
C.
D.4 r
E.
Q:
For a metals that crystallizes in face-centered cubic unit cell, what percentage of the space in the cell is occupied by the metal atoms?
A.47%
B.52%
C.68%
D.74%
E.87%
Q:
For a primitive cubic unit cell, what percentage of the space in the cell is occupied by the atoms at the corners of the cell?
A.47%
B.52%
C.68%
D.74%
E.87%
Q:
If a metal crystallizes in a primitive cubic lattice, each metal atom has ____ "nearest neighbors."
A.3
B.4
C.6
D.8
E.12
Q:
If a metal crystallizes in a body-centered cubic lattice, each metal atom has ____ "nearest neighbors."
A.3
B.4
C.6
D.8
E.12
Q:
If a metal crystallizes in a face-centered cubic lattice, each metal atom has ____ "nearest neighbors."
A.3
B.4
C.6
D.8
E.12
Q:
Arrange the three common unit cells in order from least dense to most dense packing.
A.face-centered cubic < body-centered cubic < primitive cubic
B.primitive cubic < body-centered cubic < face-centered cubic
C.primitive cubic < face-centered cubic < body-centered cubic
D.body-centered cubic < primitive cubic < face-centered cubic
E.body-centered cubic < face-centered cubic < primitive cubic
Q:
Which equation represents the number of atoms in a primitive cubic unit cell?
A.
B.
C.
D.
E.
Q:
Which equation represents the number of atoms in a face-centered cubic unit cell?
A.
B.
C.
D.
E.
Q:
Which equation represents the number of atoms in a body-centered cubic unit cell?
A.
B.
C.
D.
E.
Q:
Which one of the following statements is INCORRECT?
A.Polonium is the only metal that has a primitive cubic lattice.
B.The lattice structure of the alkali metals is body-centered cubic.
C.Many metals can crystallize in more than one type of crystal lattice.
D.Metals with a body-centered cubic lattice contain a net of four metal atoms per unit cell.
E.A hexagonal close packed structure is not an example of a cubic unit cell.
Q:
Which of the following statements concerning a metal crystallized in a face-centered cubic cell is/are CORRECT?
1/ One metal atom is located on each face of the unit cell, where it is shared equally between four unit cells.
2/ One metal atom is located at the center of the unit cell.
3/ A metal atom is located at each of the eight lattice points, where it is shared equally between eight unit cells.
A.1 only
B.2 only
C.3 only
D.1 and 3
E.1, 2 and 3
Q:
Which of the following statements concerning the cubic unit cell is/are CORRECT?
1/ For cubic unit cells, three cell symmetries occur: primitive cubic, face-centered cubic, and body-centered cubic.
2/ The cell edges of a cubic unit cell are all equal in length.
3/ The corner angles of a cubic cell are 90.
A.1 only
B.2 only
C.3 only
D.2 and 3
E.1, 2, and 3
Q:
Which of the following statements is/are CORRECT?
1/ Of the four unit cell structures in which metals crystallize, three are based on the cubic unit cell and the fourth is the hexagonal unit cell.
2/ Transition metals with high densities, especially those in period 6, preferentially crystallize with a primitive cubic cell structure.
3/ The preferred crystal structure of the Group 1A metals is face-centered cubic.
A.1 only
B.2 only
C.3 only
D.1 and 2
E.1, 2, and 3
Q:
An atom located on a face of a unit cell is shared equally between ____ unit cells.
A.2
B.3
C.4
D.6
E.8
Q:
How many unit cells share an atom which is located at a corner (or lattice point) of a unit cell?
A.1
B.2
C.4
D.6
E.8
Q:
The boiling points of some group 7A hydrides are tabulated below.gas b.p. (C)NH3 --33PH3 -88AsH3 -62Which intermolecular force or bond is responsible for the high boiling point of NH3 relative to PH3 and AsH3?A.hydrogen bondingB.dipole/induced dipole forceC.induced dipole/induced dipole forceD.covalent bondingE.dipole-dipole force
Q:
Which of the following statements concerning intermolecular forces is/are CORRECT?
1/ Dipole-dipole attractions occur in all molecules that contain polar bonds, regardless of whether the molecule has a dipole.
2/ Induced dipole/induced dipole forces exist in all molecular solids.
3/ Hydrogen bonding only occurs in all molecules containing OH bonds.
A.1 only
B.2 only
C.3 only
D.1 and 2
E.1, 2, and 3
Q:
What intermolecular force or bond is primarily responsible for the solubility of carbon dioxide (CO2) in water?
A.dipole/dipole force
B.hydrogen bonding
C.dipole/induced dipole force
D.hydrogen bonding-dipole force
E.ion-induced dipole force
Q:
Which of the following nonpolar molecules has the highest boiling point?
A.N2
B.C2H4
C.F2
D.O2
E.CS2
Q:
As pure molecular solids, which of the following exhibit only induced dipole/induced dipole forces: CO2, CH2Cl2, and SO2?
A.CO2 only
B.CH2Cl2 only
C.SO2 only
D.CO2 and CH2Cl2
E.CO2 and SO2
Q:
Which of the following statements concerning induced dipole/induced dipole forces is/are CORRECT?
1/ In general, induced dipole/induced dipole interactions decrease as the size of a molecule increases.
2/ Induced dipole/induced dipole forces are the attractive forces in molecular solids consisting of nonpolar molecules.
3/ Induced dipole/induced dipole forces exist in both polar and nonpolar molecular solids.
A.1 only
B.2 only
C.3 only
D.2 and 3
E.1, 2, and 3
Q:
Which intermolecular force or bond is responsible for the density of H2O(s) being less than that of H2O()?
A.London dispersion forces
B.hydrogen bonding
C.ionic bonding
D.covalent bonding
E.dipole/induced dipole forces
Q:
Arrange HF, HCl, and HBr in order from lowest to highest boiling point.
A.HF < HCl < HBr
B.HF < HBr < HCl
C.HBr < HF < HCl
D.HBr < HCl < HF
E.HCl < HBr < HF
Q:
Arrange H2S, H2Se, and H2Te in order from lowest to highest boiling point.
A.H2Te < H2Se < H2S
B.H2S < H2Se < H2Te
C.H2S < H2Te < H2Se
D.H2Se < H2Te < H2S
E.H2Te < H2S < H2Se
Q:
Which of the following molecules is expected to form hydrogen bonds in the pure liquid or solid phase: ethanol (CH3CH2OH), acetic acid (CH3CO2H), acetaldehyde (CH3CHO), and dimethyl ether (CH3OCH3)?
A.ethanol only
B.acetaldehyde only
C.ethanol and acetic acid
D.acetaldehyde and dimethyl ether
E.ethanol and dimethyl ether
Q:
As pure molecular solids, which of the following exhibits dipole-dipole intermolecular forces: HBr, NBr3, SBr2, and CBr4?
A.Hbr only
B.CBr4 only
C.HBr and SBr2
D.NBr3 and CBr4
E.HBr, NBr3, and SBr2
Q:
As pure molecular solids, which of the following exhibits dipole-dipole intermolecular forces: PH3, SO3, HCl, and CO2?
A.PH3 only
B.HCl only
C.SO3 and CO2
D.PH3 and HCl
E.SO3, HCl, and CO2