CP Chemistry
Final Exam Review Packet - 2014
I.
Vocabulary
solid
liquid
vapor (gas)
melting / freezing
boiling /condensing
sublimation / deposition
heat of fusion
heat of vaporization
specific heat capacity
heat
enthalpy
exothermic
endothermic
ideal gas
pressure
volume
temperature
direct proportion
inverse proportion
kinetic energy
absolute zero
STP
dissolve
concentration
molarity
equilibrium
acid
base
pH, pOH
hydronium/hydrogen ion
hydroxide ion
ionizing radiation
alpha particle
beta particle
II. Problems
Electron Configuration and Periodic table trends
1) Write out the full (longhand) electron configuration for:
a) Si
b) Ni
c) Y
2) Write out the noble gas (shorthand) electron configuration:
a) Se
b) Cs
c) Ra
3) Given the elements Al, Cs, F, Fe, N. List them in order of:
a) Increasing atomic radius
b) decreasing first ionization energy
c)
increasing electronegativity
4) Given the elements B, Cl, Li, Ne, Ra, S, W
a) Which is an alkali metal? ____
b) Which is a halogen? ______
c) Which is a chalcogen? ____
e) Which is a metalloid? ____
d) Which is a transitional metal? ____
f) Which has a complete octet in its valence? ____
5) On the periodic table, a group (or family) is a____________________ while a period is a
___________.
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6) Determine what type of bond (ionic, covalent) would form between the following pairs:
a. lithium and oxygen
b. sulfur and oxygen
c. sodium and nitrogen
d. oxygen and a halogen
Molecular Geometry
7) Complete the chart below
Compound
Lewis structure
e. an alkaline earth metal and phosphorous
Bonds
Lone pairs
Electron
geometry and
molecular
geometry
Polar or
Nonpolar
HCN
CH2Cl2
PCl3
BF3
H2S
7a. Look at your structures of BF3 and PCl3. Explain why one shape is trigional planar and one is
trigional pyramidal?
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Thermochemistry
1. Heat of Fusion / Heat of Vaporization / Heating Curve of Water
q = m ∆Hfusp or vap
e.g. How much heat is needed to melt 90.0 grams of aluminum?
q = (90.0 g) (1 mol / 27g)(10,665 J/mol)
q = 35,600 J
during
Use q = m Cp∆
a phase change
e and q = m∆H
e.g. How much energy is needed to heat 300g of water from -10C to 30C (∆Hfus = 6
kJ/mol)
3 steps are required:
1) Heat solid water from -10C to 0C
2) Melt water
3) Heat liquid water from 0C to 30C
Step 1: q = m C ∆T = (300g)(2.06 J/gC)(0 - -10C) = 6160J = 6.16 KJ
Step 2: q = m ∆H = (300g/1) (0.333 KJ/g) = 99.9 KJ
Step 3: q = m C ∆T = (300g)(4.184 J/gC)(30-0C) = 37656J = 37.66 KJ
Total = 6.16 + 99.9 + 37.66 = 143.72 KJ
8) How much energy is needed to fully vaporize 36g of water (∆Hvap = 2260J/g)
9) How much energy is needed to fully condense 36g of water at 100C (remember
sign for ∆H)
10) Determine the amount of energy released when 72g of water is cooled from
45C to -20C. Draw the heating curve associated with this question. Show the
state of the water and the boiling and/or freezing point in the diagram.
Specific Heat Capacity
q = m C ∆T
Eg. How much heat is needed to bring 90.0 grams of aluminum from 25C to 75C?
q = (90.0 g) (0.902 J/g.K) (75C - 25C)
q = 4060 J
Using m C ∆T = - m C ∆T
e.g. A 25g sample of copper at 128C is dropped into 82g of water at 34C. The final
temperature reaches 40C. Determine the specific heat of the copper.
m C ∆T = - m C ∆T (Heat in = heat out)
(82g)(4.184 J/gC)(40-34C) = -(25g)(Cp)(40-128C)
Cp = 0.94 J/gC
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11. How much heat is required to change 50.0 grams of liquid water at 60C to 90C?
12. A 34g sample of aluminum (C p = 0.902 J/gC) is heated to 100C and placed into 100g of
benzene at 20C. The final temperature of the mixture is 46C. What is the specific heat
of
the benzene?
∆Hrxn from ∆Hf
a. ∆Hrxn = ∆Hproducts - ∆Hreactants (Remember that ∆Hf for an element is zero)
e.g. Using heats of formation (with your homework on this), determine ∆Hrxn for the
following reaction:
2 CH3OH(l) + 3 O2  2CO2(g) + 4 H2O(l)
∆Hrxn = [(2 x -393.5)+(4 x -285.8)] – [(2 x -238.4) + (3 x 0)] = -1453.4
KJ/mol
b. ∆Hrxn from Bond Energy: ∆Hrxn = ∆Hbonds broken - ∆ bonds formed
13. Determine the ∆Hrxn for the following reaction:
C3H8 (g) + 5 O2 (g) → 3 CO2 (g) + 4 H2O (g)
b. Is the reaction in 7a endothermic or exothermic?
30. Use Hess’s Law to find the ΔH for the reaction below, given the following reactions
4 NH3 (g) + 5 O2 (g)  4 NO (g) + 6 H2O (g),
I.
II.
III.
N2 (g) + O2 (g)  2 NO (g)
N2 (g) + 3 H2 (g)  2 NH3 (g)
2 H2 (g) + O2 (g)  2 H2O (g)
4
ΔH = -180.5 kJ
ΔH = -91.8 kJ
ΔH = -483.6 kJ
Gases
1.
Conversions
a. Pressure conversions
1 atm = 760 mm Hg = 101.3 kPa
eg. 2.5 atm = 1900 mm Hg = 253.25 kPa
b.
Volume conversions
1 L = 1 dm3 = 1000 cm3
eg. 4.8 L = 4.8 dm3 = 4800 cm3
c.
Temperature conversion
K = C + 273
eg. -50C = 223 K
a.
Dalton’s Law of Partial Pressure
PT = P1 + P2 + P3 +…
eg. A balloon is filled with neon and helium. If the partial pressure of neon is
300 mm Hg and the partial pressure of helium is 900 mm Hg, what is the total
pressure of the gases inside the balloon?
PT = PNe + PHe
PT = 300 mm Hg + 900 mm Hg = 1200 mm Hg
b.
Boyle’s Law
P1V1 = P2V2
eg. A balloon has a volume of 0.9 L and a pressure of 3.1 atm. If the pressure is
increased to 7.1 atm, what will the new volume be?
P1V1 = P2V2
(3.1 atm)(0.90 L) = (7.1 atm) V2
V2 = 0.39 L
c.
Charles’ Law
V1 / T 1 = V 2 / T 2
eg. A balloon has a volume of 0.90 L at a temperature of 5C. What will the
volume be if the temperature is increased to 25C?
V1 / T 1 = V 2 / T 2
0.90 L / 278 K = V2 / 298 K
V2 = 0.96 L
Gas Laws
d. Gay-Lussac’s Law
P1 / T 1 = P 2 / T 2
eg. A tank with a fixed volume has a pressure of 1.00 atm at a temperature of 27C.
What will the pressure be if the temperature is increased to 227C?
P1 / T 1 = P2 / T 2
1.00 atm / 300 K = P2 / 500 K
P2 = 1.67 atm
e.
Combined Gas Law
P1V1 = P2V2
T1
T2
eg. A balloon has a volume of 0.90 L at STP. At what pressure will the balloon
have a volume of 0.40 L and a temperature of 30C?
P1V1 = P2V2
T1
T2
(1atm)(0.90 L) = P2(0.40 L)
(273 K)
(303 K)
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P2 = 2.5 atm
f.
Ideal Gas Law
PV = nRT PVM = mRT
PM = DRT
eg. A balloon contains 2.7 moles of gas at a pressure of 450 kPa and a temperature
of -20C. What is the volume of the balloon?
PV = nRT
(450 kPa) V = (2.7 moles)(8.314 kPa L)/(mol K) )(253 K)
V = 13 L
f. Avogadro’s Principle
The volume of one mole of ANY gas at STP is 22.4L – KNOW THIS AND USE
THIS!
14. Perform the following conversions:
a. 308 kPa = _____ mm Hg
b. 1040 mm Hg = _____ atm
c. 59 kPa = _____ atm
d. 56C = _____ K
15. A tank is filled with hydrogen, nitrogen, and oxygen. If the partial pressure of hydrogen is 208.1
kPa, the pressure due to oxygen is 502.9 kPa, and the total pressure of the gases in the tank is 780
kPa, what is the partial pressure of nitrogen? Does this illustrate a direct or inverse relationship?
16. Gas in a 78 cm3 container has a pressure of 8.7 atm. What will the pressure be if the gas is
transferred to a 150 cm3 container? Does this illustrate a direct or inverse relationship?
17. A gas occupies 5.1 dm3 at standard temperature. At what temperature will the gas occupy 15.3
dm3? Does this illustrate a direct or inverse relationship?
18. An air-tight, 1500-mL box contains gas at 370 kPa and 76C. What will the volume be at a
pressure of 660 kPa and -6C? Does this illustrate a direct or inverse relationship?
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19. How many moles of gas are in a 30.-L container held at 4.8 atm and 40C?
20. 56.0 grams of nitrogen dioxide occupies 2.8 L. What will be the volume of 3.1 moles of nitrogen
dioxide?
Gas Stoichiometry – Using stoichiometry and the Ideal Gas Law
g A  mol A  mol B  volume B
volume A  mol A  mol B  g B
volume A  mol A  mol B  volume B
e.g. Determine the mass of aluminum chloride produced when 44.8 L of hydrogen
chloride is reacted with aluminum at 2 atm and 45C.
2Al + 6HCl  2AlCl3 + 3H2
PV = nRT
æ 0.082Latm ö
(2atm)(44.8L) = n ç
(318K )
è molK ÷ø
n = 3.44mol
æ 3.44molHCl ö æ 2molAlCl3 ö æ 133.5g ö
çè
÷ø çè
֍
÷ = 153.08gAlCl3
1
6molHCl ø è 1mol ø
Alternately, if STP were specified, you could find the number of moles or liters simply
by remembering that 1 mole of any gas at STP has a volume of 22.4L, thus using
æ 22.4 L ö æ 1mol ö as needed.
or
çè
÷
1mol ø
çè
÷
22.4 L ø
21. What volume of oxygen at 25 degrees Celsius and 3 atm is needed to completely burn
13g of methanol (CH3OH) in an engine?
2CH3OH + 3 O2 
2CO2 +
4H2O
22. What mass of magnesium oxide will be formed if 125L of oxygen is used to burn
magnesium at STP?
2Mg + O2  2MgO
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Phase Diagrams
C
D
B
A
Be able to interpret a phase diagram
Sample problems
23. Determine on which line/curve segment the following phase changes occur:
a. Deposition __________________
b. Melting (Fusion) _______________
c. Evaporation (Vaporization) _____________________
d. Sublimation ___________________
e. Deposition ____________________
f. Condensation ___________________
24. Phase change(s) for CO2 as T goes from -60ºC to -40ºC at 6atm ______________________
25. What is the effect of increasing pressure on the boiling points of CO 2? __________________
26. What state of matter is CO2 at 20 atm and -70ºC? ________________________
27. At what temperature and pressure is CO2 is a solid, liquid, and gas? ______________
Acids and Bases/Equilibrium
pH = -(log) [H+]
pOH = -(log) [OH-]
pH + pOH = 14
[H+] = 10-pH
[OH-] = 10-pOH
1 x 10-14 = [H+][OH-]
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28. Fill in the following chart
pH
13.5
[H+]
pOH
[OH-]
2.2
3.2 x 10-9
6.3 x 10-7
29. The Ka values of hydrocyanic acid, benzoic acid, and lactic acid are 6.2 x 10 -10, 6.4x10-5, and
1.4x10-4, respectively. Which of these three acids is the strongest? Explain your answer by
showing the setup for Ka.
31. What is the pH of a 0.5 M solution of nitrous acid? (K a = 4.0 x 10-4)
32. What is the percent ionization of nitrous acid in the previous question?
33. What is the pH of a 0.02 M solution of hydrobromic acid?
34. What is the percent ionization of hydrobromic acid in the previous question?
35. Determine the direction the equilibrium will shift in for the following stresses applied:
2SO3(g) + CO2(g) + heat
CS2(g) + 4O2(g)
a. removing CO2
e. decreasing volume
b. adding heat
f. removing CS2
c. decreasing pressure
g. lowering the temperature
d. adding oxygen
h. removing SO3
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36. A) Balance the following equation and write the equilibrium expression.
__NO(g) + __H2(g)   ___N2(g) + __H2O(l)
B) Initial concentrations of NO(g) and H2(g) were 2.43 moles and 5.78 moles. They are
then mixed in a 3.00L flask. At equilibrium the flask contains 1.14 moles N 2(g). Calculate the
equilibrium concentrations of the reactants.
C) Using your responses in A and B to determine the K eq of the reaction.
37. A student carried out two separate titrations to determine the concentration of two unknown
basic solutions, “Solution A” and “Solution B.” He used a 0.01 M solution of HCl for both
titrations. Use the data table below to determine the concentrations, in mol/L, of Solutions A
and B.
Volume of Solution
Titrated (mL)
Volume of HCl needed to
Neutralize Solution (mL)
Solution A
Solution B
12
18
6
14
38. Describe the difference between a solution with a pH of 3 and a pH of 5.
39. Complete the following nuclear equations, and indicate the type of emission (alpha or beta)
a)
238
92 U
b)
234
90 Th
40.


234
91 Pa
234
90 Th
234
91 Pa
+ _____
___________________
+ ______
___________________
goes through an alpha decay, a beta decay, and a gamma decay. Write the equations
below.
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41.
How much time is required for 5.80 mg of 51Cr to decay to 1.45 mg if it has a half-life of
27.8 days?
40. An isotope of cesium has a half-life of 30 years. If 1.0 mg of cesium disintegrates over a period
of 90 years, how many mg of cesium would remain?
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