Chemistry 130: Exam #3 Review
Multiple Choice:
1. In the compound Cd2(SO3)3, what is the charge on the cadmium ion?
a. +1
b. +2
c. +3
d. +4-
2. What is the hybridization on the phosphorus atom in the molecule ICl2-?
a. sp
b. sp2
c. sp3
d. sp3d
3. The equation below is unbalanced. What coefficient should be in front of sodium phosphate?
Na3PO4 (aq) + CuCl2 (aq)  NaCl (aq) + Cu3(PO4)2 (s)
a. 1
b. 2
c. 3
d. 4
4. If you react 1.65 moles of Ba(OH)2 with 3.20 moles of HCl, how many grams of water are produced?
Ba(OH)2 (aq) + HCl (aq)  H2O (l) + BaCl2 (aq)
a. 3.20 g
b. 57.7 g
c. 59.5 g
d. 29.7 g
5. If you react 0.500 moles of C3H8 in the presence of excess oxygen, the yield of CO2 is 74.0%. What is the
actual mass of CO2 produced in the reaction?
C3H8 (g) + O2 (g)  CO2 (g) + H2O (g)
a. 66.0 g
b. 22.0 g
c. 44.0 g
d. 48.9 g
9. How many oxygen atoms are in 3.00 grams of sodium dichromate?
a. 9.85 × 1020 O atoms
b. 0.0801 O atoms
c. 6.90 × 1021 O atoms
d. 4.83 × 1022 O atoms
10. What mass of sulfur hexafluoride has the same number of fluorine atoms as 25.0 grams of oxygen
difluoride?
a. 22.5 g
b. 0.901 g
c. 203 g
Problems
1. Determine the hybridization of the central atom.
a. CH2O
b. BH4-
c. OCN-
d. CO32-
d. 8.33 g
2. Draw σ bonding, σ anti-bonding, π bonding, and π anti-bonding molecular orbitals.
a.
What is the difference between bonding and anti-bonding molecular orbitals?
b.
What is the difference between σ bonds and π bonds?
2. Draw MO diagrams for N2 and O2.
a. Classify each molecule as paramagnetic or diamagnetic.
b. Calculate the bond order for each molecule.
c. Does the bond order agree with your predictions based on the Lewis dot structure?
d. What is the hybridization on each of the atoms?
e. Between O2 and O2-, which molecule is more stable? Why?
4. Consider the following reaction:
CaCO3 (s) + HCl (aq)  CaCl2 (aq) + H2O (l) + CO2 (g)
a. Balance the equation.
b. If 2.35 g of CaCO3 reacts with 1.50 g of HCl, how many grams of CO2 gas are produced?
c. Which is the limiting reactant?
d. How many grams of the excess reactant are used?
e. What is the mass of the excess reagent that is unreacted?