Name: ____KEY_________________
Date: 3/31/14
CHM 130 Exam 2 – Chapters 12, 6, 7, 16, and 8
Show all work and clearly mark final answers to receive full credit.
1. (4 pts) Identify what type of bond (ionic or covalent) exists in the following molecules.
a. LiF ____ionic_____________
b. CCl4 ______covalent________
c. PBr3 ____covalent_________
d. K3N _____ionic_______
2. (4 pts) Circle the bonds below that are nonpolar covalent.
C–H
P – Br
I–I
C–F
3. (3 pts) Circle the atom or ion that is larger (radius) in each pair:
a. Mg
or
Mg2+
b. O
or
O2-
c. F
or
Li
4. (14 pts) Draw Lewis dot structures for the following molecules (the central atom is underlined). Then
answer the five questions below each molecule.
a. SO3
b. CH2Cl2
Number of valence electrons: ___24_____
ABE notation: __AB3_______
Molecular geometry: __triogonal planar____
Bond angles: ____120o_____
Polar molecule? ____no_______
Number of valence electrons: ___20______
ABE notation: ___AB4______
Molecular geometry: ____tetrahedral____
Bond angles: ___109.5o_____
Polar molecule? ____yes__________
5. (12 pts) Nomenclature: Complete the table below by writing correct names for given formulas or
correct formulas for given names.
CHM 130, Leedy
Formulas
Names
SO2
sulfur dioxide
Li2SO4
lithium sulfate
CoP
cobalt (III) phosphide
MgF2
magnesium fluoride
HBr (aq)
hydrobromic acid
NiS
nickel (II) sulfide
Spring, 2014
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Name: ____KEY_________________
Date: 3/31/14
6. (6 pts) Write a balanced chemical equation (including physical states) for the following reaction:
solid phosphorus reacts with oxygen gas to produce solid diphosphorus trioxide.
4 P (s) + 3 O2 (g)  2 P2O3 (s)
7. (9 pts) Balance the following chemical equations:
a. __3__ S (s) + __2__ O3 (g)  __3__ SO2 (g)
b. __1__ CH4 (g) + __2__ O2 (g)  __1__ CO2 (g) + __2__ H2O (g)
c. __2__ H2 (g) + __1__ SO2 (g)  __2__ H2O (g) + __1__ S (s)
d. __1__ CS2 (g) + __3__ O2 (g)  __1__ CO2 (g) + __2__ SO2 (g)
8. (4 pts) Identify the type of reaction for each equation shown below. Your choices are Combination
(C), Decomposition (D), Combustion (CB), Single-Replacement (SR), Double-Replacement (DR), and
Acid-Base Neutralization (AB)
a. Rxn type: ___AB____
3 NaOH (aq) + H3PO4 (aq)  Na3PO4 (aq) + 3 H2O (l)
b. Rxn type: ___SR_____
3 Mg (s) + Fe2O3 (s)  2 Fe (s) + 3 MgO (s)
c. Rxn type: ___CB_____
C2H4 (g) + 3 O2 (g)  2 CO2 (g) + 2 H2O (g)
d. Rxn type: ___D_____
2 PbSO4 (s)  2 PbSO3 (s) + O2 (g)
9. (6 pts) Predict products, including physical states, and balance each equation.
a. __2__ HF (aq) + ____ Ba(OH)2 (aq)  __BaF2 (aq) + 2 H2O (l)________
b. ____ Fe (s) + ___ Ni(NO3)2 (aq)  ____Fe(NO3)2(aq) + Ni(s)_______
c. ____ Na2CO3 (aq) + ____ Cu(NO3)2 (aq)  ___CuCO3 (s) + 2 NaNO3 (aq)______
10. (5 pts) Circle all of the following metals that will react with NaNO3.
Ca
Fe
K
Au
Na
11. (5 pts) Circle all of the compounds below that will be soluble in water.
PbCl2
BaBr2
Ag2SO4
Na2SO4
MgS
12. (4 pts) Identify what element is oxidized, reduced, the oxidizing agent, and the reducing agent for the
balanced equation below.
Zn (s) + 2 H+ (aq)  H2 (g) + Zn2+ (aq)
Reduced: _________H+______________
Oxidized: ____Zn_____________
Oxidizing agent: ____H+____________
CHM 130, Leedy
Spring, 2014
Reducing agent: _____Zn____________
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Name: ____KEY_________________
Date: 3/31/14
13. (3 pts) Complete the energy diagram below, labeling 1) transition state, 2) activation energy, and 3)
overall energy change (H) on your graph.
Bonus: 2 points. Is the reaction shown endothermic or exothermic? ___exothermic___________
Transition State
Ea
Reactants
H
Products
__C__ 14. (3 pts) Which one of the following will NOT speed up a reaction?
a. increase the reactant concentration
b. increase the temperature
c. increase the product concentration
d. add a catalyst
15. (2 pts) How many atoms are in 1 mole of lithium? ___6.02 x 1023_______
16. (3 pts) How many moles are in 5.46 x 1024 molecules of oxygen gas?
5.46 x 1024 molecules O2 (1 mole / 6.02 x 1023 atoms) = 9.07 moles O2
17. (3 pts) How many moles are in 15.4 grams of argon?
15.4 g Ar (1 mole / 39.95 g) = 0.385 mol Ar
18. (3 pts) What is the molar mass of Cu(NO3)2, with correct units!
Cu: 63.55; NO3: 14.01 + 3(16.00) = 62.01
63.55 + 2(62.01) = 187.57 g/mol
19. (4 pts) How many grams of chlorine are in 5.875 liters of bromine gas at STP?
5.875 L (1 mol / 22.4 L) (159.8 g / 1 mol) = 41.91 g of Br2
20. (3 pts) Calculate the density of steam (water vapor) at STP.
D = molar mass / molar volume = 18.02 g/mol / 22.4 L/mol = 0.804 g/L
CHM 130, Leedy
Spring, 2014
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