Name
This exam is schedule for 75 minutes and I anticipate it to take the full time allotted. You are free to leave if
you finish. Always neatly show work for partial credit. Note that lone pairs are not shown on molecules –
you need to add them. As always, a number without a unit will receive no credit.
Equation of interest:
E = q = mcT
KE = ½ mv2
1. Determine the common charge of each atom:
As (Z = 33)
Ar (Z = 18)
Sr (Z = 38)
S (Z = 16)
2. Sodium has a common charge of +1 and Oxygen has a common charge of -2. Justify this observation
based on the electron configuration of each atom.
3. Determine the molecular formula for the ionic compound that would form between each of these ions:
Sodium and oxygen ions
Magnesium and oxygen ions
Aluminum and oxygen ions
Magnesium and nitrogen ions
4. Name each of the compounds in Problem 3.
5. Octane (C8H18) and ethane (C2H6) are both molecules made up of only carbon and hydrogen.
a. Draw a Lewis Structure for each of these molecules.
b. What type of intermolecular force is experienced by each of these molecules?
c. Justify the observation that octane is a liquid at room temperature but ethane is a gas.
6. Name each of these molecules:
HCl
PF6
NaNO3
H2CO3
FeCl3
7. For each of the following atom pairs, determine if the resulting bond would be ionic, polar covalent, or
nonpolar covalent.
Te and H
Na and F
C and O
8. Justify the following data based on your understanding of intermolecular forces.
9.
Draw the Lewis Structure of each of the following:
P2F2 (connectivity FPPF)
PF2-1
PF3
10. Determine the shape around the Phosphorus in each of the following molecules:
P2F2 (connectivity FPPF)
PF3
PF2-1
11. Determine if each of the following molecules is polar or nonpolar.
P2F2 (connectivity FPPF)
PF3
12. Determine which structure(s) of the nitrite ion (NO2-1) is the most stable. You must justify your answer to
receive credit.
13. Examine the following molecule and determine the hybridization of each non-hydrogen atom and the
shape around each central atom. You are welcome to redraw the molecule in any way that you see fit.
14. Complete the following table.
Electron Configuration
Possible Anions
(Include -1, -2, and -3)
Possible Cations
(Include -1, -2, and +3)
Corresponding
Noble Gas
1s2
H-
Li+, Be2+, B3+
[He]
[Ar]
N3-, O2-, F-
15. For each of the following, determine if E > 0, E < 0, E = 0
a. A solid melts.
b. The temperature of a sample of helium changes from 46.2 ˚C to 16.1 ˚C.
c. A particle moving at 1000 m s-1 speeds up to the speed of light.
d. Solid lead at 50 ºC is transferred to 100 mL of water at 50 ºC.
𝐽
𝐽
16. 415 g of solid Bismuth (c = 0.122 𝑔℃) was placed in 100 mL of water (c = 4.184 𝑔℃) at 25 ºC. When the
two substances reach thermal equilibrium, the temperature of the water is 34 ºC. Calculate the initial
temperature of the Bismuth sample. Recall that the density of water is 1 g mL-1.
Use the following data about acetone to answer the remaining problems.
Tb (˚C)
Tm (˚C)
Hfusion (J/g)
Hvaporization (J/g)
56.05
-94.8
97.97
501.0
C (liquid)
J / (g ˚C)
2.175
C (gas)
J / (g ˚C)
1.291
17. 8560 J of energy is needed to heat 100 g of acetone from -120 ˚C to -95 ˚C. Calculate the specific heat
of solid acetone.
18. 23.176 kJ of energy is required to heat solid acetone from -94.8 ˚C to a gas at the boiling point.
Determine the mass of this sample.
Electronegativity Table