TopHat Chem Ch6 Ex

Rank each of the following compounds from most polar (1) to least polar (4).

CF4: 4 CHF3: 2 CBrF3: 3 CH2F2: 1

Based on the resonance structures shown below for NO3-, which of the following is closest to the predicted bond order for the N-O bonds as determined by Lewis theory?

1.3

Based on your above Lewis structures, which best represents the bond order of the N-C bond in these structures. For the structure with two nitrogen atoms, consider the bond between the carbon and the nitrogen that is not bonded to any other atoms.

3

Classify each of the following bonds as either: A - non-polar covalent B - polar covalent C - ionic

C-H: A C-Cl: B C≡N: B Li-O: C N-O: B O-Fe: B O=O: A C-Br: A

Which of the following molecules with a trigonal planar electron geometry will be polar? Select all that apply. The first atom listed is the central atom for all the molecules. (BF3, CH2O, SO3, PHO2)

CH2O PHO2

Use the adjust tool (the icon that looks like a cursor arrow) to measure the bond lengths of the CN and CO bonds. Give the lengths in angstroms (Å) below.

CN bond length: 1.35 CO bond length: 1.19

Using VSEPR theory, what are the electron domain geometries of the CO2 and SO2 molecules?

CO2 is linear. SO2 is trigonal planar.

Which of the following structures represents the 'best' resonance structure of the molecule PCSe-?

E

The fulminate ion has the chemical formula CNO-, where the nitrogen atom is central. Which of the following structures represents the best resonance structure for the fulminate ion? The best resonance structure is the one that is most representative of the actual molecular structure.

F

NCH, NC(CH3), NC(NH2), NC(OH), NCF Which of the above structures have multiple resonance structures?

NC(NH2) NC(OH) NCF

Based on the best resonance structure(s), what is the bond order for the N-O bond in each of the following compounds?

NOH: 2 NOBr: 2 NO2+: 2 NO2-: 1.5 NOS-: 1

In the above question, the formal charges are not listed on the resonance structures of NO3-. Determine the overall formal charge on each atom in this compound.

Nitrogen: 1 Oxygen: -0.67

For each of the following molecules, give the bond order of the individual bonds based on Lewis theory.

The N-O bond in NO-: 2 The N-O bond in NO2+: 2 The C-O bond in HCO2-: 1.5 (C is central) The N-N bond in N3-: 2

Which of the following molecular properties would be predicted to be different in the two resonance structures you have drawn?

The relative length of the C-N and C-O bonds The electron geometry of the N atom

Which is a more polar bond, the C-O bond or the S-O bond?

They have approximately the same polarity.

Which of the following structures have multiple, valid resonance structures that can be drawn for them? (The central atom is listed first in all structures.) a. CO2 b. CHO(CH3) c. CNF2- d. NHO2 e. NH3O- (originally had an error with a negative charge: NH3O-)

a. CO2 c. CNF2- d. NHO2

Which of the following compounds will have a non-zero molecular dipole? a. COH2 b. BF3 c. SO2 d. SF4 e. PBr3

a. COH2 c. SO2 d. SF4 e. PBr3

From your knowledge of molecular geometry and bond polarity, which of these molecules would you predict to be polar? a. Nitrous oxide b. Ozone c. Neither d. Both

b

Based on your knowledge of the structures of these two isomers, what can you determine about the polarity of the two compounds?

cis-KrF2Cl2 is polar. trans-KrF2Cl2 is non-polar.

Based off of the best Lewis structure, what is the expected electron domain geometry of the carbon atom of formamide?

trigonal planar

Based off of the best Lewis structure, what is the expected electron domain geometry of the nitrogen atom of formamide?

trigonal planar or tetrahedral are acceptable answers