CHEM 111 Exam 3

How many lone pairs are around the central atom in BrCl5? A. 0 lone pairs (0 non bonding electrons) B. 1 lone pair (2 non bonding electrons) C. 2 lone pairs (4 non bounding electrons) D. 3 lone pairs (6 non bonding electrons) E. 4 lone pairs (8 non bonding electrons)

B. 1 lone pair (2 non bonding electrons)

What are the H-C-H bond angles in methane (CH4)? A. 90 degrees B. 109.5 degrees C. 120 degrees D. 180 degrees E. 360 degrees

B. 109.5 degrees

What are the H-C-H bond angles in methane (CH4)? A. 90° B. 109.5° C. 120° D. 180° E. 360°

B. 109.5°

Draw the Lewis structure of SO3. What is the number of electron domains (steric number) for the central S? A. 2 B. 3 C. 4 D. 5 E. 6

B. 3

How many electron domains are around the central carbon in formaldehyde (CH2O)? A. 2 B. 3 C. 4 D. 5 E. 6

B. 3

Which of these molecules has an atom with an expanded octet? A. HCl B. AsCl5 C. ICl D. NCl3 E. Cl2

B. AsCl5

What is the empirical formula of a compound that contains 58.8% C, 9.87% H, and 31.33% O? A. C2.5H5O B. C5H10O2 C. C6H4O D. C4H8O2 E. C5H5O2

B. C5H10O2

Which of the following is the molecular formula for a compound with an empirical formula of CH2O and a molar mass of 150. g/mol? A. C7H18O3 B. C5H10O5 C. C3H6O3 D. CH2O E. None of the answers is correct

B. C5H10O5

Which of the following structures is mismatched as to whether it is polar or nonpolar? A. CO2, nonpolar B. CO, nonpolar C. H2O, polar D. CCl4, nonpolar E. F2, nonpolar

B. CO, nonpolar

A O-O bond is...and...than a O-O bond A. Longer/stronger B. Longer/weaker C. Shorter/stronger D. Shorter/weaker E. Equal in length/weaker

B. Longer/weaker

Which of the following elements has the highest electronegativity? A. Al B. P C. Ga D. Ge E. As

B. P

Which of the following compounds is/are a radical? 1. OH 2. NO 3. CO A. OH only B. NO only C. CO only D. Both OH and NO E. OH, NO, and CO

D. Both OH and NO

Which of the following is the empirical formula of a compound that is 52.15% C, 13.13% H, 34.73% O? A. C4H12O2 B. CH6O2 C. C3HO6 D. C2H6O E. None of the answers is correct

D. C2H6O

Which molecule is incorrectly matched with whether or not it has a molecular dipole? A. O2, non polar molecule B. CCl4, non polar molecule C. CHCl3, polar molecule D. NH3, non polar molecule E. CH4, non polar molecule

D. NH3, non polar molecule

Which of the following bonds is the most polar? A. Si-Si B. Si-P C. Si-S D. Si-Cl E. Cl-Cl

D. Si-Cl

The central atom in a molecule with octahedral geometry has... hybridization A. Sp2 B. Sp3 C. Sp3d D. Sp3d2 E. Sp

D. Sp3d2

Which is the correct order for increasing bond strength? (1) C(3 bonds)C (2) C=C (3) C-C A. 3<2<1 B. 3<1<2 C. 1<2<3 D. 1<3<2 E. 2<3<1

A. 3<2<1

Rank the following elements in order of increasing electronegativity (lowest to highest): Ca, Cl, Mg, Al A. Ca < Mg < Al < Cl B. Mg < Ca < Al < Cl C. Cl < Al < Mg < Ca D. Al < Cl < Mg < Ca E. Cl < Mg < Ca < Al

A. Ca < Mg < Al < Cl

What is the molecular shape around the central nitrogen in N-N-O? A. Linear B. Bent C. Trigonal planar D. Trigonal pyramidal E. Tetrahedral

A. Linear

In VSEPR theory what determines the shape of a molecule around a central atom? A. Maximal spatial separation of lone pairs, unpaired electrons, single bonds, double bonds, and triple bonds B. Maximal spatial separation of bonded atoms C. Attraction of oppositely charged groups D. Spatial separation of groups with the same charge E. Adoption of common three-dimensional solid shapes

A. Maximal spatial separation of lone pairs, unpaired electrons, single bonds, double bonds, and triple bonds

Which of the following species does NOT require resonance for the correct Lewis structure? A. OH- B. CO3 2- C. NO3 - D. O3 E. NO2

A. OH-

Which of these molecules has an atom with an expanded octet? A. PCl5 B. CH4 C. BF3 D. I2 E. C2H6

A. PCl5

Which of the following bonds is the most polar? A. Si-F B. C-F C. O-F D. S-F E. P-F

A. Si-F

The numerical value of an elements electronegativity represents... A. The ability of an atom in a bone to draw shared electrons to itself. B. The amount of energy required to remove electron from an atom. C. The amount of energy, and atom loses when it gains an electron. D. The mass of the atom E. The number of electrons in the atom.

A. The ability of an atom in a bond to draw shared electrons to itself

Why is resonance used to describe some Lewis structures? A. The true structure is an average between the different resonance structures and cannot be described by a single structure B. The true structure flips back and forth between the various resonance structures C. Electrons behave as waves when resonance occurs, but as particles when it does not D. Electrons move so fast that they seem to be two places at once E. Electrons can be two places at once

A. The true structure is an average between the different resonance structures and cannot be described by a single structure

When a covalent bond forms between two atoms, the potential energy of the system... To break a bond, energy must be... A. decreases / added B. decreased / released C. increases / added D. increases / released E. stays the same / unchanged

A. decreases / added

When a covalent bond forms between two atoms, the potential energy of the system...To break a bond, energy must be... A. decreases / added B. decreases / released C. increases / added D. increases / released E. stays the same / unchanged

A. decreases / added

At atmospheric pressure and room temperature, propane is a gas, and hexane is a liquid. We can therefore conclude that hexane... A. has stronger intermolecular forces than propane B. has weaker intermolecular forces than propane C. has the same strength intermolecular forces as propane D. has stronger covalent bonds than propane E. has weaker covalent bonds than propane

A. has stronger intermolecular forces than propane

Coconut oil is a solid at room temperature, and sunflower oil is a liquid. We can therefore conclude that coconut oil... A. has stronger intermolecular forces than sunflower oil B. has weaker intermolecular forces than sunflower oil C. has the same strength intermolecular forces as sunflower oil D. has stronger covalent bonds than sunflower oil E. has weaker covalent bonds than sunflower oil

A. has stronger intermolecular forces than sunflower oil

Electronegativity is... A. the ability of an atom in a bond to draw electrons to itself B. the amount of energy released when an atom gains an electron (per mole) C. the amount of energy required to remove an electron from an atom (per mole) D. the charge of one electron E. the potential energy that results from the interaction of charged particles

A. the ability of an atom in a bond to draw electrons to itself

Resonance structures are needed to accurately represent the structure of the nitrate ion because... A. the actual structure is a hybrid of the resonance structures B. the nitrate ion flips back and forth between the resonance structures C. the nitrate ion is negatively charged D. nitrogen had high electronegativity E. None of these. The nitrate ion does not have a resonance

A. the actual structure is a hybrid of the resonance structures

What is the molecular geometry of PH3? A. trigonal pyramidal B. square planar C. trigonal planar D. trigonal bipyramidal E. tetrahedral

A. trigonal pyramidal

Cubic zirconia is used as an inexpensive diamond substitute in jewelry. It is an oxide of zirconium (Zr) that contains 74.03% zirconium (Zr) by mass. What is the empirical formula of cubic zirconium? A. ZrO B. ZrO2 C. ZrO3 D. Zr2O E. Zr3O

B. ZrO2

A C-O bond is...and...than a C=O bond A. longer / stronger B. longer / weaker C. shorter / stronger D. shorter / weaker E. equal in length / weaker

B. longer / weaker

What is the formal charge on the central chlorine atom in the poly atomic ion ClO4 - in the Lewis structure below? A. -1 B. +1 C. +3 D. +5 E. +7

C. +3

How many equivalent resonance structures can be drawn for the nitrate ion, NO3-? A. 1 B. 2 C. 3 D. 4 E. none of these

C. 3

How many lone pairs of electrons are in the correctly drawn Lewis structure for the hydroxide ion? A. 1 lone pairs of electrons (2 nonbonding electrons) B. 2 lone pairs of electrons (4 nonbonding electrons) C. 3 lone pairs of electrons (6 nonbonding electrons) D. 4 lone pairs of electrons (8 nonbonding electrons) E. 5 lone pairs of electrons (10 nonbonding electrons)

C. 3 lone pairs of electrons (6 nonbonding electrons)

According to VSEPR theory, how many electron domains are around the P in PCl3? A. 2 B. 3 C. 4 D. 5 E. 6

C. 4

Oxalic acid is found in plants including spinach, cabbage, and rhubarb. Its empirical formula is CHO2, and its molar mass is approximately 90 g/mol. What is the molecular formula of oxalic acid? A. C3H6O3 B. C4H10O2 C. C2H2O4 D. C3H6O4 E. CHO2

C. C2H2O4

What is the molecular formula of a compound with an empirical formula of CH and a molar mass of 78.1 g/mol? A. C6H B. C2H2 C. C6H6 D. C2H6 E. CH4

C. C6H6

Which of the following molecules has multiple equivalent resonance structures? A. HF B. CH4 C. CO3 2- D. OH- E. H2O

C. CO3 2-

When a covalent bond forms between two atoms, the potential energy of the system... To break a bond, energy must be... A. Increases...added B. Increases...released C. Decreases...added D. Decreases...released E. Stays the same...unchanged

C. Decreases...addedd

Which of the following substances would you expect to have the lowest boiling point? A. KF B. Cl2 C. F2 D. Br2 E. I2

C. F2

Arrange aluminum, nitrogen, phosphorus, and indium in order of increasing electronegativity. A. Al<In<N<P B. Al<In<P<N C. In<Al<P<N D. In<P<Al<N E. None of these orders is correct

C. In<Al<P<N

When an ionic compound such as NaCl dissolves in water, which intermolecular force is most important? A. Dipole-dipole interactions B. Hydrogen bonds C. Ion-dipole interactions D. Ionic bonds E. London dispersion forces

C. Ion-dipole interactions

What is the actual bond Anatole for SO2? A. Slightly less than 109.5° B. 109.5° C. Slightly less than 120° D. 120° E. 180°

C. Slightly less than 120°

In a bond between carbon and oxygen... A. electrons are shared equally B. electrons are shared unequally; the carbon is partially negative C. electrons are shared unequally; the oxygen is partially negative D. electrons are transferred from carbon to oxygen E. electrons are transferred from oxygen to carbon

C. electrons are shared unequally; the oxygen is partially negative

Carbon and chlorine will form a/an ... bond, while potassium and bromine will form a/an ... bond A. ionic, polar covalent B. ionic, nonpolar covalent C. polar covalent, ionic D. nonpolar covalent, ionic E. nonpolar covalent, polar covalent

C. polar covalent, ionic

A N=N bond is...and... then a N-N bond A. Longer / shorter B. longer / weaker C. shorter / stronger D. shorter / weaker E. equal in length / weaker

C. shorter / stronger

Potassium sulfate, K2SO4, is used as a fertilizer to increase the potassium content of soil. What is the mass percentage of potassium in K2SO4? A. 19.35% B. 22.44% C. 28.57% D. 44.87% E. 78.20%

D. 44.87%

How many lone pairs of electrons are in the correctly drawn Lewis structure for COF2? A. 5 lone pairs of electrons (10 nonbonding electrons) B. 6 lone pairs of electrons (12 nonbonding electrons) C. 7 lone pairs of electrons (14 nonbonding electrons) D. 8 lone pairs of electrons (16 nonbonding electrons) E. 9 lone pairs of electrons (18 nonbonding electrons)

D. 8 lone pairs of electrons (16 nonbonding electrons)

What answer lists intermolecular forces by generally increasing strength? A. dipole-dipole interactions < dispersion forces < hydrogen bonds B. dispersion forces < hydrogen bonds < dipole-dipole interactions C. dipole-dipole interactions < hydrogen bonds < dispersion forces D. dispersion forces < dipole-dipole interactions < hydrogen bonds E. hydrogen bonds < dipole-dipole interactions < dispersion forces

D. dispersion forces < dipole-dipole interactions < hydrogen bonds

Which answer lists covalent bonds and intermolecular forces by generally increasing strength? A. dipole-dipole interactions<covalent bonds<dispersion forces<hydrogen bonds B. dispersion forces<hydrogen bonds<dipole-dipole interactions<covalent bonds C. Covalent bonds<dipole-dipole interactions<hydrogen bonds<dispersion forces D. dispersion forces<dipole-dipole interactions<hydrogen bonds<covalent bonds E. covalent bonds<hydrogen bonds<dipole-dipole interactions<dispersion forces

D. dispersion forces<dipole-dipole interactions<hydrogen bonds<covalent bonds

Valence bond theory describes how a covalent bond is formed by... A. the transfer of electrons from a metal atom to a nonmetal atom B. the transfer of electrons from a nonmetal atom to a metal atom C. the transfer of electrons from a nonmetal atom to a nonmetal atom D. the overlap of two orbitals, with each orbital containing one electron E. the overlap of two nuclei

D. the overlap of two orbitals, with each orbital containing one electron

What is the mass percentage of O in C3H8O2? A. 55.14% B. 21.03% C. 57.94% D. 72.58% E. 42.05%

E. 42.05%

What is the percent carbon in ethanol, CH3CH2OH? A. 13% B. 26% C. 35% D. 46% E. 52%

E. 52%

Which of the following has a Lewis structure with an incomplete octet? A. CO2 B. PCl3 C. CO D. SO2 E. BH3

E. BH3

The covalent bond with the greatest polarity would form in which of these atom pairs? A. Br—Br B. S—O C. C—P D. C—O E. B—O

E. B—O

Which intermolecular force(s) is/are found between molecules of water and ammonia, NH3? A. Ion dipole forces B. Ion dipole forces and dipole dipole forces C. London dispersion forces D. London dispersion forces and dipole dipole forces E. London dispersion forces, dipole dipole forces, and hydrogen bonding

E. London dispersion forces, dipole dipole forces, and hydrogen bonding

Valence bond theory describes how a covalent bond is formed by... A. The transfer of electrons from a metal atom to a nonmetal atom B. The transfer of electrons from a nonmetal atom to a metal atom C. The transfer of electrons from a nonmetal atom to a nonmetal atom D. The overlap of two nuclei E. The overlap of two orbitals, with each orbital containing one electron

E. The overlap of two orbitals, with each orbital containing one electron

Which intermolecular forces occur between water and ammonia (NH3) molecules? A. hydrogen bonds only B. dispersion forces only C. dispersion forces and dipole-dipole forces D. dispersion forces and hydrogen bonds E. dispersion forces, dipole-dipole forces, and hydrogen bonds

E. dispersion forces, dipole-dipole forces, and hydrogen bonds