Chemistry I Final Exam Study Guide
Essay
1.
Write a balanced chemical equation for the following reaction: iron plus copper(I) nitrate yields iron(II) nitrate plus copper.
2.
In terms of the periodic law, explain which two of these elements are most similar: sodium (element 11), phosphorus (element 15), and sulfur (element
16).
3.
Draw the orbital diagram for phosphorus.
4.
Each of four students separately makes four measurements of the mass of the same object. The readings are as follows:
Student 1: 9.1 g, 9.2 g, 9.1 g, 9.1 g
Student 2: 11 g, 9 g, 9 g, 11 g
Student 3: 14.1 g, 11.0 g, 17.4 g, 18.8 g
Student 4: 10.1 g, 9.9 g, 10.0 g, 10.0 g.
The real value of the object's mass is 10.0 g. Evaluate each student's set of readings in terms of precision and accuracy.
5.
Determine the number of significant digits in each of the following measured values:
(a) 6.7090; (b) 0.0384; (c) 12,000; (d) 3400.; (e) 100.050.
6.
Calculate the volume of a rectangular pan that is 27.0 cm long, 14.55 cm wide, and 9.3 cm high. (Remember to retain only significant digits in your
final answer and to express your answer in the proper units.)
7.
A student measures the mass of an object as 135.80 g. Calculate the percent error in the measurement, given that the accepted value for the mass is
137.23 g.
8.
Find the measured mass of a sample if the accepted value is 20 grams and the percent error is 2 percent.
9.
Calculate the density of an object that occupies 17.1 cm3 and has a mass of 39.26 g. Will that object float in water, given that the density of water is
1.00 g/cm3? Explain your answer.
10.
Convert 73.0 seconds to weeks. Express your answer in scientific notation.
11.
Calculate how many meters are in one mile (39.37 inches = 1 meter). Express your answer in scientific notation.
12.
Identify the element that has the following electron configuration: 1s22s22p63s23p64s23d104p65s24d105p2. How many unpaired electrons are present?
13.
Suppose you have just discovered three new elements. Element 1 is a solid at room temperature, a fair conductor of heat and electricity, and not ductile.
Element 2 is a solid at room temperature and lustrous. Element 3 is a gas at room temperature and a poor conductor of heat and electricity. Classify
each element as either a metal, nonmetal, or semimetal. Explain your reasoning. Then state one additional property that each element is likely to have.
14.
Compare and contrast precision and accuracy.
15.
Describe the different principles that govern the building of an electron configuration.
16.
Explain what is meant by the Heisenberg uncertainty principle.
17.
Explain nuclear charge and how it affects the general trend in radii of atoms of elements going from left to right across a period in the periodic table.
18.
Describe the trends in the atomic size of elements within groups and across periods in the periodic table. Provide examples.
19.
Explain how ions form. Provide examples.
20.
Describe the trends in first ionization energy within groups and across periods in the periodic table. Provide examples.
21.
Positive ions are smaller than the atoms from which they are formed, but negative ions are larger than the atoms from which they are formed. Explain
why this is so.
22.
Describe the trends in electronegativity within groups and across periods in the periodic table. Provide examples.
23.
How many different kinds of covalent bonds can a nitrogen atom form? Explain.
24.
Explain why ionic bonds tend to form between metals and nonmetals.
25.
Describe the differences among single, double, and triple bonds. Use specific compounds to illustrate your answer.
26.
Compare the properties of a nonpolar covalent bond to those of a polar covalent bond.
27.
Consider the equation O2(g) + CS2(l)  CO2(g) + SO2(g). How does the equation violate the law of conservation of mass? How can the equation be
rewritten to conform to the law of conservation of mass?
28.
Write the word equation and balanced formula equation for the reaction in which chlorine reacts with potassium to produce potassium chloride, KCl.
29.
Write the word equation and balanced formula equation for the reaction in which calcium nitride is formed from calcium and nitrogen.
30.
Lithium metal reacts with water to form aqueous lithium hydroxide, LiOH, and hydrogen gas. Write a balanced chemical equation for the reaction.
31.
Iron(III) nitrate reacts with potassium sulfide to form aqueous potassium nitrate and solid iron(III) sulfide. Write a balanced chemical equation for the
reaction.
USING SCIENCE SKILLS
Figure 6-2
32.
Using Tables and Graphs Write a description to place in box (2) in Figure 6-2.
33.
Using Tables and Graphs What compound name belongs in box (1) in Figure 6-2?
34.
Classifying What type of bond belongs in box (3) in Figure 6-2?
35.
Classifying What type of bond belongs in box (4) in Figure 6-2?
36.
Comparing and Contrasting How are metallic bonds and ionic bonds similar? How are they different?
Substances
Compound
Remarks
A
potassium, K, and
iodine, I
KI
Iodine is a member of the halogen group; potassium
is an alkali metal.
B
carbon, C, and
oxygen, O
CO2
Carbon and oxygen are both nonmetals.
C
Al, O, and H
Al(OH)3
OH- (hydroxide) is a polyatomic ion.
Figure 6-3
37.
Applying Concepts How does the saying “Opposites attract” apply to the bonding in the compound shown in row A of Figure 6-3?
38.
Comparing and Contrasting What kind of bond forms between the elements in row B of Figure 6-3? How is this type of bond different from the type
of bond that forms between the elements in row A?
39.
Comparing and Contrasting How are the compounds in rows A and C in Figure 6-3 similar? How are they different?
40.
Inferring A hydroxide ion has a charge of 1–. What is the charge on the aluminum ion? Explain your answer. Use Figure 6-3 to answer this question.
41.
Predicting Suppose you could substitute sulfur, S, for iodine in row A in Figure 6-3. What would the formula for the resulting compound be? Explain
your answer.
Chemistry I Final Exam Study Guide
Answer Section
ESSAY
1.
2.
3.
4.
5.
6.
ANS:
Fe(s) + 2CuNO3(aq)  Fe(NO3)2(aq) + 2Cu(s)
PTS:
1
DIF:
II
REF:
2
OBJ:
2
ANS:
Their locations in the periodic table indicate that phosphorus and sulfur are nonmetals and sodium is a metal. Nonmetals are a group with characteristic
properties, so phosphorus and sulfur are the most similar elements of the three.
PTS:
ANS:
1
DIF:
III
REF:
1
OBJ:
3
PTS:
1
DIF:
III
REF:
3
OBJ:
3
ANS:
Student 1's results cluster together closely, so they have relatively high precision. However, they are not clustered about the correct value, 10.0, but are
significantly off, so they are relatively inaccurate. Student 2's results do not cluster together closely, so they are imprecise. However, they are averaged
around the correct value, 10.0, so as a set of data they are fairly accurate. Student 3's results are far apart and are far off the correct value, even when
averaged, so they are both imprecise and inaccurate. Student 4's results cluster together closely and are close to the correct value, so they are both
precise and accurate.
PTS:
1
OBJ:
1A 1.f
ANS:
(a) five; (b) three (the two zeros are not significant); (c) two (the three zeros are not significant); (d) four; (e) six
PTS:
1
OBJ:
1A 1.g
ANS:
volume = length  width  height
= 27.0 cm  14.55 cm  9.3 cm
= 3653.505 cm3, which must be rounded to two significant digits to match the uncertainty in 9.3 cm, so the final answer should be reported,
after rounding, as 3700 cm3, or 3.7  103 cm3.
PTS:
1
ANS: 1.04%
OBJ:
1A 1.g
7.
PTS:
ANS:
1
20.4 grams
OBJ:
1A 1.h
8.
PTS:
ANS:
1
OBJ:
1A 1.h
9.
PTS:
ANS:
1
OBJ:
1A 1.i
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
PTS:
ANS:
1
OBJ:
1A 1.j
PTS:
1
OBJ:
1A 1.j
ANS:
The element must be tin (Sn, atomic number 50), given the number of electrons present and their distribution. There are two unpaired electrons, in the
5p sublevel.
PTS:
1
OBJ:
4D 4.h
ANS:
Element 1 has properties that are typical of semimetals; another property it is likely to have is moderate luster. Element 2 has properties that are typical
of metals; another likely property is the ability to conduct heat and electricity. Element 3 has properties that are typical of nonmetals; another likely
property is nonmalleability (if converted to a solid).
PTS:
1
OBJ:
5E 5.d
ANS:
Precision and accuracy are both evaluations of the reliability of measured values. Precision refers to repeatability of values, or closeness compared to
one another. Accuracy refers to the closeness of values to the correct or standard value.
PTS:
1
OBJ:
1A 1.f
ANS:
The aufbau principle states that electrons enter the orbitals of lowest energy first. The Pauli exclusion principle states that each orbital can hold only
two electrons. Hund's rule states that electrons first enter separate orbitals of the same energy, with each electron having the same spin, before pairing
with electrons that have opposite spins.
PTS:
1
DIF:
L3
REF:
p. 133 | p. 134 | p. 135 | p. 136
OBJ:
5.2.1 | 5.2.2
ANS:
The measurement of the speed or position of a moving particle necessarily involves an interaction with the particle. Therefore, the position or the speed
of the particle is changed as a result of the measurement. As a consequence, accurate measurements of both these variables cannot be made at the same
time.
PTS:
1
DIF:
L3
REF:
p. 145
OBJ:
5.3.4
ANS:
Nuclear charge is the attraction an atomic nucleus has on the electrons surrounding it. As you move from left to right across a period, the atomic
number increases, and therefore the number of protons in the nucleus increases. The more protons within a nucleus, the greater is the nuclear charge. A
greater nuclear charge pulls the electrons closer to the nucleus, decreasing the atomic radius.
PTS:
1
DIF:
II
REF:
3
OBJ:
2
ANS:
Atomic size increases with increasing atomic number within a group. For example, sodium atoms are larger than lithium atoms, and potassium atoms
are larger than sodium atoms. Atomic size decreases with increasing atomic number across a period. For example, lithium atoms are larger than
beryllium atoms, and beryllium atoms are larger than boron atoms.
PTS:
1
DIF:
L2
REF:
p. 171
OBJ:
6.3.1
STA:
SC.HS.1.1.1| SC.HS.1.1.5
ANS:
Ions form when electrons are transferred among atoms. For example, a group 1A element, such as potassium, tends to transfer one electron to other
atoms, causing it to form a net positive charge, in this case K . Such ions with net positive charges are called cations. Ions with net negative charges
are anions. Nonmetal atoms, such as chlorine, tend to accept electrons from other atoms. Chlorine tends to gain a single electron, forming the anion Cl
.
20.
PTS:
1
DIF:
L2
REF:
p. 172
OBJ:
6.3.2
ANS:
First ionization energies decrease from top to bottom within a group and increase across a period from left to right. For example, the first ionization
energy of rubidium is less than that of lithium. The first ionization energy of iodine is much greater than that of lithium.
21.
22.
23.
24.
25.
26.
27.
28.
29.
PTS:
1
DIF:
L2
REF:
p. 174
OBJ:
6.3.3
ANS:
When an electron is added to an atom, the attraction of the nucleus for any one electron decreases and the size of the ion’s radius increases. When an
electron is removed from an atom, there is an increase in the nuclear attraction experienced by the remaining electrons. Consequently, the remaining
electrons are drawn closer to the nucleus.
PTS:
1
DIF:
L3
REF:
p. 176
OBJ:
6.3.3
ANS:
Electronegativity values decrease from top to bottom within a group, and from right to left across a period. For example, rubidium is less
electronegative than lithium. Lithium is less electronegative than fluorine.
PTS:
1
DIF:
L3
REF:
p. 177
OBJ:
6.3.3
ANS:
A nitrogen atom has five valence electrons. To have a complete octet of electrons, the nitrogen atom forms three covalent bonds. It could form three
single bonds, one single, and one double bond, or one triple bond.
PTS:
1
DIF:
II
REF:
2
OBJ:
5
ANS:
Ionic bonds form between elements with electronegativity differences greater than 2.0. Metals tend to have low electronegativity while nonmetals have
high electronegativity. Metals will more easily give up electrons to nonmetals, whose atoms are more likely to accept electrons.
PTS:
1
OBJ:
7G 7.a
ANS:
A single bond results from the sharing of a single pair, or two electrons. A double bond shares two pairs, or four electrons. A triple bond shares three
pairs, or six electrons. Student answers may include ammonia (single bonds), formaldehyde (double bond), and ethyne (triple bond).
PTS:
1
OBJ:
7G 7.c
ANS:
A polar covalent bond occurs between two atoms that differ in electronegativities by 0.4 to 1.9. This bond will have an unequal sharing of electrons,
with one of the atoms being slightly negative and the other being slightly positive. In contrast, the nonpolar covalent bond will have roughly equal
sharing of electrons between atoms and no separation of charge. The electronegativity difference between the two atoms will be less than 0.4.
PTS:
1
OBJ:
7G 7.d
ANS:
In the equation shown, there are more oxygen atoms in the products than in the reactants and more sulfur atoms in the reactants than in the products.
Both conditions violate the law of conservation of mass. The equation is balanced as follows: 3O2 + CS2  CO2 +2SO2.
PTS:
1
DIF:
II
ANS:
chlorine + potassium  potassium chloride
Cl2 + K  KCl
PTS:
1
OBJ:
ANS:
calcium + nitrogen  calcium nitride
Ca + N2  Ca3N2
REF:
2
OBJ:
2
9I 9.b
30.
PTS:
1
OBJ:
9I 9.b
ANS:
2 Li(s) + 2 H2O(l)  2 LiOH(aq) + H2(g)
31.
PTS:
1
OBJ:
9I 9.b
ANS:
2 Fe(NO3)3(aq) + 3 K2S(aq)  6 KNO3(aq) + Fe2S3(s)
32.
PTS:
1
OBJ:
9I 9.b
ANS:
The atoms of a metal lose one or more valence electrons and form cations. The atoms of a nonmetal gain one or more electrons and form anions. There
is an attraction between the oppositely charged ions.
33.
PTS:
1
BLM:
comprehension
ANS:
sodium chloride
DIF:
L2
OBJ:
6.1.3
STA:
SC-HS-1.1.7.B | SC-HS-1.1.7.B | SC-HS-1.1.7.A
PTS:
BLM:
DIF:
L1
OBJ:
6.3.2
STA:
SC-HS-1.1.7.B
1
knowledge
34.
35.
36.
37.
38.
39.
40.
41.
ANS:
covalent
PTS:
1
BLM:
knowledge
ANS:
metallic
DIF:
L1
OBJ:
6.2.1
STA:
SC-HS-1.1.5 | SC-HS-1.1.5 | SC-HS-1.1.7.A
PTS:
1
DIF:
L1
OBJ:
6.4.1
STA:
SC-HS-1.1.5
BLM:
knowledge
ANS:
In both metallic and ionic bonds, there are attractions between particles with positive and negative charges — cations and electrons in a metallic bond,
and cations and anions in an ionic bond. Ionic bonds are found in compounds. Metallic bonds are found in a single metal or in alloys.
PTS:
1
DIF:
L3
OBJ:
6.1.3 | 6.4.1
STA:
SC-HS-1.1.7.B | SC-HS-1.1.5 | SC-HS-1.1.7.B | SC-HS-1.1.7.A | SC-HS-1.1.5 BLM:
synthesis
ANS:
Potassium is a highly reactive metal with one valence electron. Iodine is a highly reactive nonmetal with seven valence electrons. When electrons are
transferred from potassium atoms to iodine atoms, there is an attraction between the oppositely charged ions that form. Thus, opposites do attract in an
ionic bond.
PTS:
1
DIF:
L2
OBJ:
6.1.3
STA:
SC-HS-1.1.7.B | SC-HS-1.1.7.B | SC-HS-1.1.7.A
BLM:
comprehension
ANS:
Covalent bonds form between the nonmetals carbon and oxygen. In a covalent bond, atoms share electrons. When potassium and iodine react, electrons
are transferred from potassium atoms to iodine atoms. Ionic bonds form between potassium cations and iodide anions. There is no sharing of electrons
in an ionic bond.
PTS:
1
DIF:
L3
OBJ:
6.1.3 | 6.2.1
STA:
SC-HS-1.1.7.B | SC-HS-1.1.5 | SC-HS-1.1.7.B | SC-HS-1.1.7.A | SC-HS-1.1.5 | SC-HS-1.1.7.A
BLM:
synthesis
ANS:
The compounds in rows A and C are both ionic compounds. However, KI is a binary ionic compound, which forms between a metal and a nonmetal.
The compound in row C contains a polyatomic hydroxide ion (OH–). The atoms within a polyatomic ion are joined by covalent bonds.
PTS:
1
DIF:
L2
OBJ:
6.3.1
BLM:
analysis
ANS:
The charge on the aluminum ion is 3+. The formula Al(OH)3 indicates that there are three hydroxide ions for each aluminum ion in aluminum
hydroxide. Since each hydroxide ion has a 1– charge, each aluminum ion must have a charge of 3+ for the overall charge on the compound to be zero.
PTS:
1
DIF:
L2
OBJ:
6.1.4 | 6.3.1 | 6.3.2
STA:
SC-HS-1.1.7.B
BLM:
application
ANS:
K2S; because sulfur has six valence electrons, its atoms gain two electrons when they form ionic compounds. Potassium atoms donate one valence
electron when they form ionic compounds. It takes two potassium atoms to donate two electrons to one sulfur atom.
PTS:
1
DIF:
L2
OBJ:
6.1.1
BLM:
application