Chemical bonding 2
123-
Which of the following pairs of atoms will form a polar covalent bond? Choose from : C & S, H & B, O& O,
Mg & Br, K & Cl
How many double bonds must be formed to write the correct Lewis Structure for NCl 3?
Consider the following three structures for the thiocyanate ion. Which of these structures has an atom
with a formal charge of -1?
4567-
Which of the following elements can have an expanded octet? Choose from: O,Cl, N, H, He
How many equivalent resonance forms can be drawn for the sulfur trioxide (SO3) molecule?
Consider the molecules PCl3, PCl5, and SiH4. Which of these molecules is polar?
Consider the correct Lewis structure for the hypothetical molecule ZQ2 that is shown in the figure. Which
of the following is closest to the expected Q-Z-Q bond angle in this molecule?
8-
What is the hybridization of the carbon atom indicated by the arrow in the following figure?
9-
What will be the electron geometry in a molecule with three bonding domains and one lone pair of
electrons around the central atom?
10- How many sigma and pi bonds are present in the molecule depicted?
11- What types of intermolecular forces will be present in a pure sample of the compound shown in the
figure?
12- Which of the following would you expect to have the highest boiling point? Choose from: C8H18, CH4,
C4H10, C2H6, C3H8
13- Consider the following phase diagram. If a substance were to start at the temperature and pressure
indicated by the x, what phase change would occur as the result of decreasing the pressure at constant
temperature?
14- How much energy (in kJ) is necessary to convert 2.50 mol of ethanol from liquid to gas at 78.3 oC?
15- Which of the following species can hydrogen bond with water? Choose from: CH4, H2S,HF, H2Se,
CH3Cl
16- Use the table to answer questions about bond energies.
Bond
Bond
energy
(kJ/mol)
C−C
347
C=C
611
C−H
414
C−O
360
C=O
799
O−O
142
O=O
498
H−O
464
Part A
Calculate the bond energy for breaking all the bonds in a mole of methane, CH 4 .Express your answer
to four significant figures and include the appropriate units.
Part B
Calculate the bond energy for breaking all the bonds in a mole of O 2 molecules? Express your answer to
three significant figures and include the appropriate units.
Part C
Calculate the bond energy for forming all the bonds in a mole of water molecules,
answer to three significant figures and include the appropriate units.
H 2 O .Express your
Part D
Calculate the bond energy for forming all the bonds in a mole of carbon dioxide, CO 2 .
Express your answer to four significant figures and include the appropriate units.
17- Consider the following four molecules. Which of these satisfy the octet rule and which do not?
PF5,CS2,BBr3,CO3-2
18- How many lone pairs are on the central atom in BCl 3 ?
19- How many lone pairs are on the central atom of BrF 3 ?
20- The Lewis structure for the chlorate ion is
Calculate the formal charge on the chlorine
(Cl ) atom. Express your answer as an integer. Calculate the formal charge on each of the oxygen
(O ) atoms labeled a , b , and c in the following Lewis structure. Express your answers as integers
separated by commas.
21- What are the formal charges on the sulfur (S ), carbon (C ), and nitrogen (N ) atoms, respectively,
in the resonance structure that contributes most to the stability of the thiocyanate ion, SCN − ?
The possible resonance structures for the thiocyanate ion, SCN − , are
Express your answers as integers separated by commas.
formal charge on sulfur (S ), carbon (C ) and nitrogen (N ) atoms =