Exam 4 SI Review
1) What will happen if you place a piece of Al metal in a solution of Zn2+ ions?
2) Which of the follwing reactions are spontaneous? Why?
a) Al + 3K+→ 3K + Al3+
c) Au + 3Ag+→ 3 Ag + Au3+
b) 3K + Al3+ → Al + 3K+
d) 3Ag + Au3+ → Au + 3Ag+
3) Consider the following galvanic cell:
a) Which way will the electrons flow in the wire?
b) What is the oxidizing agent? The reducing agent?
c) Label the anode and cathode. Which loses mass and which gains mass?
d) If KNO3 is the salt in the salt bridge, draw which direction the salt ions would
flow?
4) Which of the following metals would protect iron from rusting?
Zinc
Tin
Magnesium
Nickel
5) Why is the boiling point of H2O so much higher than that of H2S?
6) True or False: All substances experience London dispersion forces
7) Consider the following series of molecular compounds to answer the following:
H3P
H2S
H2Se
H2Te
a) List all the intermolecular forces experienced by each of the molecules?
b) Which molecule will have the highest boiling point?
8) Circle the compound(s) that will exhibit hydrogen bonding:
9) SiO2 melts at 1710 ˚C. What type of solid is SiO2?
Molecular
Ionic
Network
Metal
10) CaCl2 is a solid that melts at 772 ˚C. What type of solid is CaCl2?
Molecular
Ionic
Network
Metal
11) Which has stronger London dispersion forces?
SiH4
or
CH4
CO
or
CO2
H2O
or
H2S
11) How many mL of water are needed to make a 0.675 M NaCl solution using 54.5 g NaCl?
12) How many moles of calcium chloride are there in 150 mL of 1.56 M calcium chloride solution?
13) You have two aqueous solutions, one 0.065 Molar Fe(NO3)3 and the other 0.15 M (NH4)2CO3. If you
combine 120.0 mL of each solution, what is the theoretical yield of iron (III) carbonate Fe2(CO3)3 in
grams? The molar mass of iron (III) carbonate is 292 g. Show all work, include units, and report your
answer to the correct number of significant figures.
2 Fe(NO3)3(aq) + 3 (NH4)2CO3(aq) → Fe2(CO3)3(s) + 6 NH4NO3(aq)
14) How many grams of Na2SO4 are needed to make 56.7 mL of 0.975 M Na2SO4 solution?
15) What concentration of AgNO3 would result from the addition of 0.825 L water to 1.65 L of 0.934 M
AgNO3 solution?
16) How many mL of 1.625 M H3PO4 are needed to neutralize 136.7 mL of 1.435 M NaOH?
17) Which of the following will freeze at the lowest temperature? The highest temperature?
a) 0.1 M Aluminum Nitrate
b) 0.2 M Calcium Chloride
d) 0.1 M Magnesium Phosphate
c) 0.1 M Sodium Sulfate
e) 0.2 M Sodium Chloride
f) 0.5 M Glucose (C6H12O6)
18) Which of the following are colligative properties of a solution? (Circle all that apply)
Decreased Melting Point
Decreased Boiling Point
Decreased Vapor Pressure
Increased Freezing Point
Increased Melting Point
Increased Vapor Pressure
Increased Boiling Point
Decreased Freezing Point
19) Complete the following chart showing the physical properties of water as it is heated from -20 ˚C to
120 ˚C and label the different phases as well as the physical processes occurring (ie: melting,
vaporization, sublimation or freezing:
20) If ∆E total < 0, the substance will/ will not dissolve, the solution will/ will not form and the solution
will get warmer/colder. (Circle the correct answers)
21) Which would dissolve better in water: CCl4 or NaCl
22) As temperature increases, solubility generally increases/decreases (circle the correct answer)
23) As pressure decreases, gas solubility generally increases/decreases (circle the correct answer)
24) If you increase the concentration of a solution you ___________ the number of collisions between
molecules, and therefore the reaction will proceed __________.
25)Do reactions proceed slower or faster at higher temperatures? Justify your answer.
26) For a particular reaction, the reactants are at 80 kJ, the products are 60 kJ, and the transition state is
at 150 kJ. Sketch a reaction-energy profile showing both ∆𝐸𝑟𝑥𝑛 and 𝐸𝑎 . Also, calculate the value of
∆𝐸𝑟𝑥𝑛 and 𝐸𝑎 , and state whether this reaction is endothermic or exothermic. Solve for reverse reaction
as well. How does a catalyst affect ∆E of these reactions?
27) Determine the rate law and overall order from the following reaction.
Experiment
1
2
3
2 NO(g) + O2(g) → 2 NO2(g)
[NO] (M)
[O2] (M)
0.0126
0.0125
0.0252
0.0125
0.0252
0.0250
28) The mechanism for the reaction of A2 with B is:
Step 1: A2 + Y → AY + A (slow)
Step 2: A + B → AB (fast)
Step 3: AY + AB → Y + A2B (fast)
a) Write the overall reaction that is occurring
b) Which step determines the rate law for the reaction?
c) Write the rate law for the reaction
d) What happens to the rate of the reaction when [A2] is doubled?
e) Which species is the catalyst?
f) Which species are reaction intermediates?
Rate
1.41 x 10-2
5.64 x 10-2
1.13 x 10-1