HONORS CHEMISTRY – FINAL EXAM REVIEW – SPRING 2014
STRATEGY: Start by reading through your notes (chapters 8 – 15, and 18) to refresh your memory on these topics. Then, use this review sheet as a starting point to identify the areas on which you need to spend more study time. For those areas, go back to homework assignments, and notes to practice more problems. These questions are only samples and do not include specific examples of how vocabulary and other conceptual information might appear in a multiple-choice or other format.
FORMAT:
¨ Questions will include 65 multiple-choice and 2 Essay/Calculations.
¨ You will be given a periodic table and formula sheet.
Chapter 8: Balancing Equations
Decomposition (D), Synthesis (S), Single Replacement (SR), Double Replacement (DR), Combustion (C), Neutralization (N)
S 1. 2 H2 + O2 è 2 H2O
N 2. H3PO4 + 3 KOH è K3PO4 + 3 H2O
SR 3. 6 K + B2O3 è 3 K2O + 2 B
S 4. 6 Cs + N2 è 2 Cs3N
C 5. 2 C6H6 + 15 O2 è 12 CO2 + 6 H2O
DR 6. BaCl2(aq) + K2(SO4) è 2 KCl + BaSO4
S 7. N2 + 3 H2 è 2 NH3
C 8. 2 C10H22 + 31 O2 è 20 CO2 + 22 H2O
N 9. Al(OH)3 + 3 HBr è AlBr3 + 3 H2O
DR 10. CaBr2 + Na2CO3 è CaCO3(aq) + 2 NaBr(aq)
Chapter 9: Stoichiometry
1. Ideal combustion, resulting in only carbon dioxide and water, rarely happens. In general, at the very least, some carbon monoxide is also produced. The real combustion of methane is more closely represented, then, by the unbalanced equation CH4 + O2 è H2O + CO2 + CO. If 0.100 mol CH4 is allowed to react with 3.20 g O2, what is the limiting reagent, how many grams of carbon monoxide will be produced, and how many liters of the excess reactant will be left over when the reaction has gone to completion, assuming the reaction occurs at STP?
3 CH4 + 5 O2 è 6 H2O + CO2 + 2 CO
0.100 mole CH4 │ 2 mole CO │ 28.01 g CO = 1.87 g CO
│ 3 mole CH4 │ 1 mole CO
3.20 g O2 │ 1 mole O2 │ 2 mole CO │ 28.01 g CO = 1.12 g CO
│ 32.00 g O2 │ 5 mole O2 │ 1 mole CO
1.87 g CO
- 1.12 g CO 0.75 g CO │ 1 mole CO │ 3 mole CH4 │ 22.4 L CH4 = 0.89 L CH4
0.75 g CO │ 28.01 g CO │ 2 mole CO │ 1 mole CH4
2. Elemental zinc, Zn, reacts violently with elemental sulfur, S8. If 1020. g of zinc react with 1.210 x 1024 atoms of
sulfur, what is the limiting reagent, how many moles of product are produced?
8 Zn + S8 è 8 ZnS
1020. g of Zn │ 1 mole Zn │ 8 mole ZnS = 15.60 mole ZnS
│ 65.39 g Zn │ 8 mole Zn
1.210 x 1024 atoms S8 │ 1 mole S8 │ 8 mole ZnS = 16.07 mole ZnS
│ 6.022 x 1023 atoms S8 │ 1 mole S8
Zn is the LR
3. 25.0 mL of 0.350 M NaOH are added to 45.0 mL of 0.125 M copper (II) sulfate. How many grams of precipitate will be formed? (0.427 grams copper II hydroxide) What are the molar concentrations of all the species remaining in the solution? (0.0179 M copper ions, 0.125 M sodium ions, and 0.0804 M sulfate ions)
Chapter 10: States of Matter - Solids Liquids and Gases
1. Which of the following is NOT a characteristic of ionic substances?
a. Are usually gases at room temperature. c. Have high melting points.
b. Conduct electricity in solution form. d. Usually dissolve in water.
2. Which of the following is NOT a characteristic of metallic substances?
a. Malleable and ductile. c. Have low melting points.
b. Conduct electricity. d. Are usually solids at room temperature.
3. Which of the following is NOT a characteristic of covalent substances?
a. Have low melting points. c. Form individual molecules.
b. Sometimes dissolve in water. d. Conduct electricity.
4. What is the difference between an intermolecular force and an intramolecular force?
- What are the three types of intramolecular forces?
Ionic bond, Covalent, bond, and Metallic bond
- What are the three types of intermolecular forces?
Hydrogen bonding, Dipole-dipole, and London Dispersion Forces
- Arrange the intermolecular and intramolecular forces from weakest to strongest.
LDF, D-D, H. Bonding, (ionic, covalent, and metallic) bonding
5. What causes dipole-dipole interactions?
The cause of the dipole moment in a compound is due to the difference in electron affinity of the atoms that are
bonded in the compound.
6. Why is hydrogen bonding only possible with hydrogen?
Hydrogen is the only element that has an exposed proton when an electron is lost. The exposure of the proton and the fact that the other element that the hydrogen in bonded to has a very high electron affinity, the compound ends up having a very strong dipole moment called hydrogen bonding.
7. What are the three possible elements that hydrogen atom must be attached to, in a compound, in order for the compound to contain hydrogen bonding? N, O, and F
8. Explain how London dispersion forces arise. Although London dispersion forces exist among all molecules, for what type of molecules are they the only major intermolecular forces? Are London dispersion forces relatively strong or relatively weak? Explain. LDF are created by a momentary polarity due to a valence electron moving out of its normal orbit. Nonpolar molecules are the only type of molecules in which LDF is the major intermolecular force of attraction. LDF are the weakest force of attraction.
9. What causes surface tension? The forces of attraction from molecule to molecule (intermolecular force – hydrogen bonding) are much stronger than the attraction for the objects that the liquid comes in contact with.
10. Why is ice less dense than water? The density of ice is less because when ice is formed, the water molecules form rings that create more space between the molecules.
11. What is the reasoning behind Chlorine being in a gaseous state, bromine being in a liquid state, and iodine being in a solid state? LDF increases as the size of the atom increases. Since the size of the atoms increase from Cl2 to Br2 to I2, the forces of attraction (LDF) are strong enough for the states to go from gaseous state, to liquid state to solid state for the respective molecules.
12. Specify the predominant force of attraction that would affect the boiling point of the compound and list it immediately following the substance. Then in the last column, indicate which member of the pair you would expect to have the higher boiling point. Possible forces of attraction are: metallic bonding, ionic bonding, network covalent bonding, hydrogen bonding, dipole-dipole and London dispersion forces
Substance #1 / Predominant Intermolecular Force / Substance #2 / Predominant Intermolecular Force / Substance with Higher Boiling Pointa. HCl(l) / Dipole-dipole / I2 / LDF / HCl(l)
b. CH3F / Dipole-dipole / CH3OH / Hydrogen bonding / CH3OH
c. H2O(l) / Hydrogen bonding / H2S / Dipole-dipole / H2O(l)
d. SiO2(s) / Network covalent bonding / SO2 / Dipole-dipole / SiO2(s)
e. Fe(s) / Metallic Bonding / Kr / LDF / Fe
f. CH3OH(l) / Hydrogen bonding / CuO(s) / Ionic bonding / CuO
g. NH3 / Hydrogen bonding / CH4 / LDF / NH3
h. HCl(g) / Dipole-dipole / NaCl / Ionic bonding / NaCl
i. SiC / Network covalent bonding / Cu(s) / Metallic Bonding / SiC
13. Draw a Heating Curve Diagram and label where each of the following would either be located on the
curve or label on what part of the curve it would be used to complete calculations.
a. Solid e. Liquid i. Vapor
b. Specific Heat of Solid f. Specific Heat of Liquid j. Specific Heat of Vapor
c. Melting/Freezing g. Vaporizing/Condensing
d. Heat of Fusion h. Heat of Vaporization
14. What formula is used to calculate the amount of energy needed to change the phase of a substance?
Q = DH x moles (heat/energy = enthalpy of ______x mole of substance)
15. CCl2F2 has a boiling point of -30. °C, and a heat of vaporization of 0.165 kJ/g. The vapor and the liquid have
specific heats of 0.61 J/g·K and 0.97 J/g·K respectively. How much heat must be evolved when 10.0 g of
CCl2F2 is cooled from +40. °C to -40. °C?
Q = mCpDT = (10.0 g)( 0.61 J/g·K)(70. K) = 430 J
Q = DH x mass = (0.165 kJ/g)(10.0 g) = 1.65 kJ = 1650 J
Q = mCpDT = (10.0g)(0.97 J/g·K)(10 K) = 97 J
– 2180 J
(It is negative because energy is given off.)
16. For the following Phase Change Diagrams, identify what states are in sections A, B, and C and what occurs when each line is crossed (in each direction). What is the point D called? What is the point E called? Which of the diagrams is the Change of State Diagram for water? How can you tell?
A – solid, B – liquid, C – gas, going across the line from: A to B melting occurs, B to A freezing occurs, B to C vaporization occurs, C to B condensation occurs, A to C sublimation, C to A deposition. D is the triple point. E is the critical point. The first diagram is the diagram for water because the line between A and B leans to the left indicating that the density of the solid is less than the density of the liquid.
Chapter 11: Gas Laws
1. What does Boyle’s Law state, what is the formula, and what is held constant?
– the volume of a fixed mass of gas varies inversely with the pressure at constant temperature.
P1V1 = P2V2 (at constant temperature and moles)
2. What does Charles’ Law state, what is the formula, and what is held constant?
– the volume of a fixed mass of gas at constant pressure varies directly with the Kelvin temperature.
V1 = V2 (at constant pressure and moles)
T1 T2
3. What does Avogadro’s Law state, what is the formula, and what is held constant?
4. What is the formula for the Combined Gas Law and what is held constant?
– expresses the relationship between pressure, volume, and temperature of a fixed amount of gas.
P1 V1 = P2 V2
T1 T2
5. What is the formula for the Ideal Gas Law and what is the value and units on R?
PV = nRT R = 0.0821 L ▪ atm / mole ▪ K
6. What is diffusion and effusion? What is the formula that is used for these calculations?
Diffusion – the random movement of gases from an area of higher concentration to an area of lower concentration
in open space.
Effusion – the random movement of gases from an area of higher concentration (in a closed container) to an area
of lower concentration (outside of the container) through a small hole or opening in the container.
Formula for calculating diffusion: Distance A = mB
Distance B mA
Formula for calculating effusion: Velocity A = mB
Velocity B mA
7. 1 mole of any gas at STP = 22.4 L
8. The conversion factors for Pressure are equal to:1.00 atm = 760. mm = 760. torr = 101.3 kPa
9. A 2.00 L sample of a gas originally at 25 oC and a pressure of 700. torr is allowed to expand to a volume of
5.00 L. If the final pressure of the gas is 585 torr, what is its final temperature in Celsius? 350. oC
10. A gas has a volume of 350. mL at 740. torr. How many milliliters will the gas occupy at 900. torr if the
temperature remains constant? 288 mL
10. Calculate the number of liters occupied by the following at STP:
a. 0.200 moles of oxygen 4.48 L
b. 12.4 grams of chlorine gas 3.92 L
c. a mixture of 0.100 moles of nitrogen gas and 0.500 moles of oxygen gas 13.4 L
11. From the volume, temperature and pressure listed below, calculate the number of moles for the gas:
750.0 cm3 at 27.0 oC and 99.0 kPa. 0.0298 moles
12. A balloon has a volume of 2.0 L indoors at a temperature of 25.0 oC. If it is taken outdoors on a very cold day when the temperature is –28.9 oC, what will its volume be in liters? Assume a constant air pressure within the balloon. 1.6 L
13. Calculate the volume of 6.00 g of hydrogen gas at 24.0 oC and 1.50 atm. 48.3 L
14. Calculate the mass of 24.5 mL of SO2 gas at STP. 0.0701 g
15. If excess hydrochloric acid is added to 13.5 grams of Al, what volume of hydrogen gas will be produced if
the gas is collected at a temperature of 80.0 oC and a pressure of 750. torr? 22.1 L
16. At a certain temperature, the velocity of chlorine molecules is 0.0410 m/s. What is the velocity of sulfur dioxide molecules at the same temperature and pressure? 0.0431 m/sec
17. What is the ratio of the speed of carbon monoxide molecules to that of nitrogen monoxide molecules when both gases are at the same temperature? 1.04 : 1 (rate CO : rate NO)
18. The rate of effusion of an unknown gas was determined to be 2.92 times faster than that of ammonia. What is the approximate molecular weight of the unknown gas? 2.00 g/mole
19. In the reaction, N2 + H2 è NH3, how many mL of nitrogen, measured at STP, are required to produce 400 mL of NH3, measured at STP? How many mL of hydrogen are required at STP? a. 200 mL N2 b. 600 mL
Chapter 12: Solutions
1. What is molarity (M), molality (m), normality (N), and mass percent?
M = mole of solute / liter of solution, m = moles of solute / kg of solvent, N = M x number of equivalents,
mass % = mass of solute / mass of solution x 100 or part over whole x 100
2. What term is used to describe a substance dissolving? solubility
3. What is a solid – solid solution of two or more metals called? alloy