1ST SEMESTER FINAL EXAM FOR CHEMISTRY HONORS, 2014-15 (STUDY GUIDE)
GENERAL DESCRIPTION: A large part of the 1st semester final exam is made up of 200 Scantron-marking questions. Most of the questions are matching exercises. In the matching exercises,
the answer choices may be used once, more than once, or not at all! Within the 200 questions,
there are 5 standard multiple-choice questions. The general organization of this test is as follows:
CONTENT
CHAPTER 1
(Categories of Substances)
CHAPTER 1
(Element, Compound, Solution,
Colloid, Suspension)
CHAPTER 1
(Methods for
Separating Mixtures)
CHAPTER 1
(States of Matter)
CHAPTER 2
(Basic Scientific Method Terms)
CHAPTER 2
(Significant Figures)
CHAPTER 2
(Density)
# of Q’S
TYPE
5
Matching
5
Matching
Element, Compound, Solution,
Colloid, Suspension
5
Matching
Chromatography, Crystallization,
Distillation, Filtration
5
Matching
Gas, Liquid, Plasma, Solid
5
Matching
5
Matching
5
Matching
CHAPTER 3
(Accuracy and Precision)
5
Matching
CHAPTER 2
(Measurement)
5
M/C
5
Matching
10
Matching
5
Matching
CHAPTER 2
(Metric Prefixes)
CHAPTER 3
(Atomic Structure)
CHAPTER 3
(Atomic Structure)
CHAPTER 3
(Same#/Different# of
Protons/Neutrons)
5
Matching
CHAPTER 3
(Atomic Laws)
5
Matching
CHAPTER 4
(Development of
Quantum Theory)
5
Matching
ANSWER CHOICES
Elements, Compounds, Mixtures,
Elements and Compounds
Chemistry, Experiment,
Procedure, Units, Variable
1 sig. fig.; 2 sig. figs.; 3 sig. figs.;
4 sig. figs.; 5 sig. figs.
mass, volume, 5.0, 9.0, 45
Both accurate and precise;
Accurate, but not precise;
Precise, but not accurate;
Neither accurate nor precise.
Given a measurement image,
select the correct numerical
value of the measurement
Centi-, Kilo-, Mega-,
Micro-, MilliProton, Electron, Neutron,
Atomic Number, Mass Number
2, 3, 4, 7, 9
Same # of Protons, but Different # of
Neutrons; Same # of Neutrons, but
Different # of Protons;
Different #’s of Neutrons and Protons
Law of Conservation of Matter;
Law of Definite Proportions;
Law of Multiple Proportions
Bohr Model, Electrons as Waves,
Heisenberg Uncertainty Principle,
Line-Emission Spectra,
Photoelectric Effect
Aufbau Principle, Hund’s Rule,
Pauli Exclusion Principle,
Noble Gas Shorthand
1
1s , 1s22s1, 1s12s1, 1s22s22p6,
1s22s22p62d103s2
Angular Momentum Quantum #,
Magnetic Quantum #,
Principle Quantum #, Spin Quantum #
d-orbital, f-orbital,
p-orbital, s-orbital
Actinides, Alkali Metals,
Alkaline Earth Metals,
Lanthanides, Transition Metals
Atomic Radius, Electron Affinity,
Electronegativity, Ionization Energy
Boron/Carbon Groups, Chalcogens,
Halogens, Pnictogens, Noble Gases
Atomic Number, Atomic Mass,
Chemical Symbol,
Electron Configuration
Gains One (Electron), Gains Two,
Gains Three, Loses One, Loses Two
CHAPTER 4
(Electron Configuration)
10
Matching
CHAPTER 4
(Electron Configuration)
5
Matching
CHAPTER 4
(Quantum Numbers)
5
Matching
CHAPTER 4
(Orbital Shapes)
5
Matching
CHAPTER 5
(Metals)
10
Matching
5
Matching
10
Matching
5
Matching
5
Matching
5
Matching
Covalent Bond, Ionic Bond
15
Matching
Anion, Cation, Ionic Compound,
Monatomic Ion, Polyatomic Ion
CHAPTER 5
(Properties of Elements)
CHAPTER 5
(Nonmetals)
CHAPTER 5
(Reading the Periodic Table)
CHAPTER 6
(Ion Formation)
CHAPTER 6
(Ionic Bond/Covalent Bond)
CHAPTER 6
(Ionic Compounds
and Components)
All single bonds; All double bonds;
One single and one double bond;
One single and one triple bond;
One quadruple bond.
Molecule, Multiple Bond,
Octet Rule Exception,
Resonance, Unshared Pair
Nonpolar Covalent,
Polar Covalent,
Ionic
CHAPTER 6
(Covalent Bonding: Single, Double,
Triple, and/or Quadruple Bonds)
10
Matching
CHAPTER 6
(Covalent Bonding Concepts)
5
Matching
5
Matching
5
Matching
AX, AX2, AX3, A2X, A3X
5
Matching
AX, A2X3, A3X2, A2X, A3X
10
Matching
Two (2); Three (3); Four (4);
Six (6); Twelve (12)
CHAPTER 6
(Bond Type Using a Table of
Electronegativity Values)
CHAPTER 7
(Ionic Compound Formulas; A is the
Cation and X is the Anion)
CHAPTER 7
(Ionic Compound Formulas; A is the
Cation and X is the Anion)
CHAPTER 7
(Counting Atoms)
There will also be a test part that has formula-writing and compound-naming problems.
Study Guide
1.
2.
3.
4.
5.
6.
Elements are pure substances made of only one kind of atom. Compounds are pure substances
made from the atoms of two or more elements that are chemically bonded. Mixtures are
blends of two or more kinds of matter, each of which retains its own identity and properties.
Element, Compound, Solution, Colloid, and Suspension problems:
a. If the problem contains an element (written out) from the Periodic Table, then it is an
ELEMENT (A). Ignore the adjectives and state of matter! If not (A), go to step b.
b. If the problem contains a formula with 2 or more element symbols combined, then it is
a COMPOUND (B). Examples are H2O and CO2. If not (B), go to step c.
c. If the mixture (solutions, colloids, and suspensions are all mixtures) contains solids and
liquids such that the solids part of the mixture would sink to the bottom of the
container, then it is a SUSPENSION (E). If not (E), go to step d.
d. If the mixture is transparent (you could see through it), then the mixture is a
SOLUTION (C). If not (C), go to step e.
e. All that remains is a colloid. As a check, is it a mixture like milk that you cannot see
through? If it is, then it is a COLLOID (D).
Chromatography is a term for techniques used to separate mixtures of compounds according
to their distribution between a mobile phase and a stationary phase. Subtle differences
among the compounds and their affinities for each phase can result in separation due to the
differential retention on the stationary phase. This is often used to separate dyes.
Crystallization is the formation of solid crystals from a homogeneous solution. It is a solidliquid separation technique. In order for crystallization to take place, a solution must be
"supersaturated". “Supersaturated” refers to a state in which the liquid (solvent) contains
more dissolved solids (solute) than can ordinarily be accommodated at that temperature.
Distillation is a method of separating liquid mixtures based on differences in their
component’s volatilities in a boiling liquid mixture. The vapors are condensed and collected.
Filtration is the process of separating suspended particles from a liquid/solid or gas/solid
mixture by forcing the liquid/gas portion of the mixture through a porous material in which
the liquid/gas can pass while the suspended particles are retained on the porous material.
Solid has definite volume and definite shape. Liquid has definite volume but indefinite shape.
Gas has neither definite volume nor definite shape. Plasma is a high-temperature physical
state of matter in which atoms lose their electrons.
Chemistry is the study of the composition, structure, and properties of matter and the
changes it undergoes. An Experiment is a test under controlled conditions that is made to
demonstrate a known truth, examine the validity of a hypothesis, or determine the efficacy
of something previously untried. A Procedure is a detailed, and often lengthy, step-by-step
set of directions to re-create the experiment for anyone. A Unit of measurement is a
definite magnitude of a physical quantity, defined and adopted by convention and/or by law,
that is used as a standard for measurement of the same physical quantity. A Variable is a
characteristic, number, or quantity that increases or decreases over time, or takes different
values in different situations.
Significant Figures: (1) Non-zero digits are always significant; (2) Any zeros between two
significant digits are significant; (3) If there is a decimal point, left-side leading zeros are
not significant; (4) If there is a decimal point, right-side trailing zeros are significant; (5) If
there is no decimal point, right-side trailing zeros are not significant; and (6) all of the
7.
8.
9.
10.
11.
12.
13.
14.
numbers in the argument part of a number in scientific notation are significant. Examples:
3.0800 gives 5 sig. figs.; 0.00418 gives 3 sig. figs.; 250.0 gives 4 sig. figs.; 7.09 x 10-5 gives 3
sig. figs.; 92000 gives 2 sig. figs.; 0.0030050 gives 5 sig. figs.; and 250.0 gives 4 sig. figs. For
multiplication or division, the answer can have no more significant figures than are in the
measurement with the fewest number of significant figures. When adding or subtracting
decimals, the answer must have the same number of digits to the right of the decimal point as
there are in the measurement having the fewest digits to the right of the decimal point.
Density is equal to Mass ÷ Volume. It has units of g/cm3 or g/mL.
Accuracy is the closeness of measurements to the correct or accepted value. The average of
a set of measurements is used when making this comparison. Precision is the closeness of a
set of measurements of the same quantity made in the same way. Precise data has a “tight”
pattern.
Measurement entails reporting the value(s) known with certainty and then adding one extra
digit that is estimated with some degree of uncertainty. If one would estimate a value of
uncertainty if the measurement were to fall between units, but in actuality the measurement
is coincident with a unit mark, an uncertain digit of zero must be added. Example: If the
tenths were uncertain and the value fell on the 3 unit, the value would be reported as 3.0
units.
Metric Prefixes: 1000 nano’s make 1 micro. 1000 micro’s make 1 milli. 1000 milli’s make 1 noprefix. 1000 no-prefix’s make 1 kilo. 1000 kilo’s make 1 mega. 1000 mega’s make 1 giga. There
is one more which is not a multiple of 1000: 100 centi’s make 1 no-prefix.
Atomic Structure: In a neutral atom, Atomic Number = Protons = Electrons. Protons +
Neutrons = Mass Number. Protons and Neutrons have most of the mass in atoms. Protons are
positively charged. Neutrons are neutral. Electrons have negligible mass, are fast moving,
deflectable by magnets, and are negatively charged. Isotopes are atoms with the same atomic
number but a different number of neutrons.
The Law of Conservation of Matter states that matter is neither created nor destroyed
during ordinary chemical reactions or physical changes. The Law of Definite Proportions
states that a chemical compound contains the same elements in exactly the same proportions
by mass regardless of the size of the sample or source of the compound. The Law of Multiple
Proportions states that if two or more different compounds are composed of the same two
elements, then the ratio of the masses of the second element combined with a certain mass
of the first element is always a ratio of small whole numbers.
The Bohr Model of the hydrogen atoms states that an electron can circle the nucleus only in
allowed paths or orbits. Electrons as Waves results from de Broglie’s hypothesis that
electrons have wave-like properties. This has been verified by passing a collated beam of
electrons through a thin crystal and obtaining a diffraction pattern. The Heisenberg
Uncertainty Principle states that it is impossible to determine simultaneously both the
position and velocity of an electron or any other particle. Line-Emission Spectra are observed
when electric currents are passed through vacuum tubes containing gases at low pressure and
the resulting narrow beams of emitted light are separated optically into series of specific
wavelengths. The Photoelectric Effect refers to the emission of electrons from a metal when
light of sufficient energy shines on the metal.
Electron Configuration: According to the Aufbau Principle (from the German word meaning
“building up”), an electron occupies the lowest-energy orbital that can receive it. According to
the Pauli Exclusion Principle, no two electrons in the same atom can have the same set of four
quantum numbers. This means that for two electrons in the same orbital, one electron must be
“spin-up” and one electron must be “spin-down.” According to Hund’s Rule (the Empty Bus
Seat Rule), orbitals of equal energy are each occupied by one electron before any orbital is
occupied by a second electron, and all electrons in singly occupied orbitals must have the same
spin. The Noble Gas Shorthand is a way to write simpler electron configurations. Example:
Mg with 1s22s22p63s2 becomes [Ne]3s2 in noble gas shorthand. The standard orbital filling
order is given as shown here: 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p6.
15. Quantum Numbers: The Principle Quantum Number, symbolized by n, indicates the main
energy level occupied by the electron. The Angular Momentum Quantum Number, symbolized
by l, indicates the shape of the orbital. The Magnetic Quantum Number, symbolized by m,
indicates the orientation of an orbital around the nucleus. The Spin Quantum Number has
only two possible values, +½ and -½, which indicate the two fundamental spin states of an
electron in an orbital.
16. Orbital Shapes: The s-orbital is spherical. The p-orbital resembles a dumbbell. The
d-orbital has a three-dimensional clover-leaf shape. The f-orbital has eight lobes, four
directed downward and four directed upward.
17. Metals: The Alkali Metals occupy Group 1A and all have a single s-electron for their valence
electron. These metals all react vigorously with water. The Alkaline Earth Metals occupy
Group 2A and all have a filled s-orbital for their valence electrons. The Transition Metals are
d-block elements in that the d-orbitals are being filled as one goes across the periods within
the d-block. The Lanthanides (called rare-earths) involve the filling of the 4f orbitals. The
Actinides involve the filling of the 5f orbitals. All of the actinides are radioactive.
18. Atomic Radius is defined as one-half the distance between the nuclei of identical atoms that
are bonded together. Unlike most Periodic Table trends, atomic radius increases as one goes
down a family. This is due to electrons occupying sublevels in successively higher main energy
levels located farther away from the nucleus. Electron Affinity is the energy change that
occurs when an electron is acquired by a neutral atom. Electronegativity is a measure of the
ability of an atom in a chemical compound to attract electrons. The most electronegative
element is fluorine. Ionization Energy is the energy required to remove one electron from a
neutral atom of an element.
19. Nonmetals: The Boron Group includes those elements in Group 3A. This group is headed by
boron, which is a metalloid. The Carbon Group includes those elements in Group 4A. Carbon, in
the form of diamond, is the hardest known element. The Pnictogens are those elements in
Group 5A, also known as the Nitrogen Group. Nitrogen makes up over three-fourths of the
Earth’s atmosphere. The Chalcogens are those elements in Group 6A, also known as the
Oxygen Group. Oxygen is used by aerobic organisms such as us for the biological process of
respiration. The Halogens are those elements in Group 7A. These elements are extremely
reactive and have common uses as disinfectants. The Noble Gases are those elements in
Group 8A. These gases are generally unreactive.
20. Ion Formation: Group 1A elements lose 1 electron to achieve the noble gas configuration.
Similarly, Group 2A elements lose 2 electrons. Group 4A elements may lose or gain 4 electrons
to achieve a noble gas configuration, but generally gain 4. Similarly, Group 5A elements gain 3
electrons, Group 6A elements gain 2 electrons, and Group 7A elements gain 1 electron.
21.
22.
23.
24.
25.
26.
Covalent Bonding results from the sharing of electrons. This situation typically occurs
between nonmetals. Covalent bonding may yield multiple bonds. Ionic Bonding results from the
transfer of electrons. This situation typically occurs between a metal and a nonmetal.
Ionic Compounds and Components: An Anion is a negative ion formed by the gain of one or
more electrons. A Cation is a positive ion formed by the loss of one or more electrons. Ionic
Compounds are high melting, hard, and brittle, form crystals, and yield conducting solutions.
A Monatomic Ion is an ion formed from a single atom. A Polyatomic Ion is an ion formed
from multiple elements bonded together covalently.
Covalent Bonding (Single, Double, Triple, and/or Quadruple Bonds):
a. Know the total number of valence electrons for the compound. Each H contributes one
electron; each Group 4A element contributes 4; each Group 5A element contributes 5;
each Group 6A element contributes 6; each Group 7A element contributes 7; and
electrons are added for each unit of negative charge or taken away for each unit of
positive charge.
b. Arrange electrons around the elements (for the structure given) so that, with sharing,
each element has a filled configuration. Hydrogen needs two electrons for a filled
configuration, while all other elements need eight. Boron is an exception and typically
requires only six.
c. All electrons between two elements are fully shared. You cannot take only the ones you
want the element to take. Thus, in ::O::O:::O::, the O on the left would have 8
electrons including sharing, the O in the middle would have 10, and the O on the right
would also have 10. Therefore, THE STRUCTURE WOULD NOT BE CORRECT! Electron
pairs would need to be moved to unshared positions on the tops and bottoms of the O’s.
d. A:A has a single bond; B::B a double bond; C:::C a triple bond; D::::D a quadruple bond.
A Molecule is a neutral group of atoms that are held together by covalent bonds. Multiple
Bonds typically refers to double and triple bonds, but also may refer to quadruple bonds.
Most main-group elements tend to form covalent bonds in accordance with the octet rule.
There are, however, Octet Rule Exceptions. Under certain circumstances, B, P, S, Cl, As, Se,
Br, Sb, Te, and I will form covalent compounds that are exceptions to the octet rule.
Resonance refers to bonding in molecules or polyatomic ions that cannot be correctly
represented by a single Lewis structure. An Unshared Pair is a pair of electrons that is not
involved in bonding and that belongs exclusively to one atom.
Bond Type Using a Table of Electronegativity Values: One subtracts the electronegativity
value of one element from that of the other element involved in the chemical bond. If
necessary, one takes the absolute value of this difference to get a positive number. If the
difference is 0.0 to 0.5, the bond is determined to be Nonpolar Covalent. If the difference is
0.6 to 1.5, the bond is determined to be Polar Covalent. If the difference is 1.6 or greater,
the bond is determined to be Ionic.
Writing Ionic Compound Formulas:
a. Determine the charge of the cation, A, using the considerations detailed above in
section titled Ion Formation. For example, Group 2A magnesium will lose two electrons
to become Mg2+. Similarly, determine the charge of the anion, X, using the same
considerations. For example, Group 7A fluorine will gain one electron to become F-.
27.
28.
29.
30.
b. If the charges are equal and opposite, like 3+ and 3-, just put the two parts together.
Example: Al3+ and N3- go together to give AN. In an A-X formulation, this would be
written as AX.
c. If the charges are unequal, use the crisscross rule to find the subscripts. Example:
Mg2+ and F- go together by crisscross to give MgF2. In an A-X formulation, this would
be written as AX2.
d. If crisscross gives you a combination that can be reduced, it must be. Example: Mg2+
and C4- give Mg4C2 by crisscross. It must be reduced to Mg2C to be correct. In an A-X
formulation, this would be written as A2X.
Counting Atoms:
a. The subscript gives the number of atoms of the element to the left of it. For NH3
there are 1 N and 3 H’s.
b. A subscript outside a parenthesis acts as a multiplier for each of the elements
contained within the parentheses. Ga2(SO4)3 would have 2 Ga’s, 3 S’s, and 12 O’s.
c. Some elements occur in multiple places and must be added up in order to get the total.
Ammonium gluconate, NH4C6H11O7, has hydrogen in two places: 4 + 11 give 15 H’s.
Writing More Complex Ionic Compound Formulas:
a. Determine or recall from memory the formulas and charges of the ions. Roman
numerals, when associated with the element name, provide one with the charge of the
ion. Ex. V(III) means that the ion is V3+.
b. If the charges are equal and opposite, like 3+ and 3-, just put the two parts together.
Example: Al3+ and PO43- go together to give AlPO4. There are NO PARENTHESIS FOR
A SINGLE POLYATOMIC ION IN A CHEMICAL FORMULA!
c. If the charges are unequal, use the crisscross rule to find the subscripts. Example:
Ca2+ and OH- go together by crisscross to give Ca(OH)2. Here you need parentheses
for the polyatomic ion, OH-, because there are more than one of them in the compound.
Another example: NH4+ and CO32- go together by crisscross to yield (NH4)2CO3.
d. If crisscross gives you a combination that can be reduced, it must be. Example: Ti4+
and HPO42- give Ti2(HPO4)4 by crisscross. It must be reduced to Ti(HPO4)2 to be
correct.
Naming Ionic Compounds: This is the reverse of the above process. Recall from memory the
two component parts: the cation name and the anion name. Put the cation name first and the
anion name second. The only tricky part is making sure that you have a Roman numeral
associated with the cation when it needs one. Ions that need Roman numerals are typically
transition metals. However, Zn2+, Ag+, and Cd2+ are exceptions and must not have a Roman
numeral. Tin and lead are non-transition metals that must have a Roman numeral. Example: In
Sn(SO4)2, the anion is sulfate with a -2 charge. Two sulfates give -4, so tin (IV) with a +4
charge gives a balanced charge. Therefore, the name is tin(IV) sulfate.
Writing Covalent Compound Formulas and Naming Covalent Compounds: Covalent compounds
use the counting prefixes, mono, di, tri, tetra, penta, hexa, etc. for both the first and second
parts of these compounds. If there is only one first element, MONO IS NOT USED. For the
second element, a prefix must be used. The first element has the element name unchanged.
The second element must be the –ide form of the element name. Examples: N2O is dinitrogen
monoxide. Sulfur hexafluoride is SF6.
Oxidation Numbers of Monatomic Ions
2+
cadmium, Cd
2+
3+
1+
2+
+
zinc, Zn
silver, Ag
ammonium, NH4+
Charges of Common Polyatomic Ions
1acetate, CH3COObicarbonate, HCO3bromate, BrO3chlorate, ClO3chlorite, ClO2cyanide, CNdihydrogenphosphate,
H2PO4-
2-
hydroxide, OHhypochlorite, ClOnitrate, NO3nitrite, NO2perchlorate, ClO4permanganate, MnO4hydrogensulfate, HSO4-
carbonate, CO32chromate, CrO42dichromate, Cr2O72hydrogenphosphate,
HPO42oxalate, C2O42peroxide, O22sulfate, SO42sulfite, SO32
3phosphate, PO43arsenate, AsO43-
Use a P.T. and this table to
write formulas and name
compounds correctly.
Vanadium (III) peroxide
Cobalt (III) hydrogenphosphate
SrBr2
Cadmium phosphide
Cesium nitrite
KClO4
Chromium (III) chloride
Cobalt (II) oxalate
V(ClO3)3
Ammonium dichromate
Tin (II) sulfite
Sn3N4
Aluminum arsenate
Copper (I) bicarbonate
ZnCO3
Magnesium sulfide
Vanadium (IV) carbide
SnCrO4
Iron (II) acetate
Strontium fluoride
CoPO4
Ammonium chromate
Manganese (II) cyanide
Hg(HSO4)2
Zinc hydrogensulfate
Nitrogen monoxide
Al(ClO2)3
Tin (IV) hypochlorite
Disulfur dichloride
(NH4)2SO4
Lead (IV) sulfate
Tetraphosphorus pentoxide
Ba(H2PO4)2
Copper (II) dihydrogenphosphate
Xenon hexafluoride
Fe2O3
Barium permanganate
NH4ClO
Na3AsO4
Calcium chlorate
Pb3P4
Mg(OH)2
Ammonium oxide
Mn2C
Cr2(O2)3
Silver chlorite
PbC2O4
LiNO2
Mercury (II) iodide
Cs2Cr2O7
FeF2
Beryllium carbonate
CaSO3
Nb(MnO4)5
Sodium phosphate
CuS
CuHCO3
Iron (III) bromide
BeCl2
V(NO3)4
Potassium nitrate
NH4I
CO2
Lithium nitride
Co(CH3COO)2
PCl5
Lead (II) hydroxide
AgCN
N2O
Niobium (V) perchlorate
CdHPO4
P4S6