Transcript crs_tb_ch02 - ChemConnections

Chapter 2
Atoms, Molecules,
and Ions
QUESTION
According to the law of multiple proportions:
1) if the same two elements form two different
compounds, they do so in the same ratio.
2) it is not possible for the same two elements
to form more than one compound.
3) the ratio of the masses of the elements in a
compound is always the same.
4) the total mass after a chemical change is
the same as before the change.
5) none of these
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CRS Question, 2–2
ANSWER
5)
none of these
Section 2.2 Fundamental Chemical Laws (p. 41)
The Law of Proportions states that when two
elements form more than one compound, the
masses of one element in these compounds for
a fixed mass of the other element are in ratios of
small whole numbers.
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CRS Question, 2–3
QUESTION
Which of the following pairs of compounds can
be used to illustrate the law of multiple
proportions?
1) NH4 and NH4Cl
2) ZnO2 and ZnCl2
3) H2O and HCl
4) NO and NO2
5) CH4 and CO2
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CRS Question, 2–4
ANSWER
4)
NO and NO2
Section 2.2 Fundamental Chemical Laws (p. 41)
These are two compounds containing the same
two elements, but in different ratios: 1:1 and 1:2.
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CRS Question, 2–5
QUESTION
Which of the following statements from Dalton’s
atomic theory is no longer true, according to modern
atomic theory?
1) Elements are made up of tiny particles called
atoms.
2) Atoms are not created or destroyed in chemical
reactions.
3) All atoms of a given element are identical.
4) Atoms are indivisible in chemical reactions.
5) All of these statements are true according to
modern atomic theory.
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CRS Question, 2–6
ANSWER
3)
All atoms of a given element are identical.
Section 2.3 Dalton’s Atomic Theory (p. 43)
Since Dalton’s time we have learned that two
atoms of the same element can have different
numbers of neutrons. These are called isotopes.
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CRS Question, 2–7
QUESTION
The first people to attempt to explain why
chemical changes occur were
1) alchemists.
2) metallurgists.
3) physicians.
4) physicists.
5) the Greeks.
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CRS Question, 2–8
ANSWER
5)
the Greeks.
Section 2.1 The Early History of Chemistry
(p. 39)
The origins of history, medicine, philosophy and
mathematics can be traced back to the Greeks
as well.
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CRS Question, 2–9
QUESTION
The first chemist to perform truly quantitative
experiments was
1) Paracelsus.
2) Boyle.
3) Priestly.
4) Bauer.
5) Lavoisier.
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CRS Question, 2–10
ANSWER
2)
Boyle.
Section 2.1 The Early History of Chemistry
(p. 39)
These experiments included his work with the
relationship between the pressure and volume of
a gas.
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CRS Question, 2–11
QUESTION
What element (in trace amounts) has been
shown to help in protecting against heart
disease and cancer?
1) Silicon
2) Oxygen
3) Selenium
4) Copper
5) Potassium
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CRS Question, 2–12
ANSWER
3)
Selenium
Section 2.3 Dalton’s Atomic Theory (p. 43)
Selenium has been shown to be an important
trace mineral for human beings. It appears to be
an integral part to the structure of several
enzymes.
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CRS Question, 2–13
QUESTION
The first scientist to show that atoms emit any
negative particles was
1) J. J. Thomson.
2) Lord Kelvin.
3) Ernest Rutherford.
4) William Thomson.
5) John Dalton.
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CRS Question, 2–14
ANSWER
1)
J. J. Thomson.
Section 2.4 Early Experiments to Characterize
the Atom (p. 45)
The particles were studied by J.J. Thomson
during his cathode ray tube experiments in the
last part of the nineteenth century.
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CRS Question, 2–15
QUESTION
The scientist whose alpha-particle scattering
experiment led him to conclude that the nucleus
of an atom contains a dense center of positive
charge is
1) J. J. Thomson.
2) Lord Kelvin.
3) Ernest Rutherford.
4) William Thomson.
5) John Dalton.
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CRS Question, 2–16
ANSWER
3)
Ernest Rutherford.
Section 2.4 Early Experiments to Characterize
the Atom (p. 45)
As the atomic number increases the number of
neutrons of stable atoms increases at a higher
rate.
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CRS Question, 2–17
QUESTION
Which of the following atomic symbols is
incorrect?
1)
2)
3)
14
C
6
37
Cl
17
32
P
15
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4)
5)
39
K
19
14
N
8
CRS Question, 2–18
ANSWER
5)
14
8
N
Section 2.5 The Modern View of Atomic
Structure: An Introduction (p. 49)
The subscript is the atomic number. Nitrogen’s
atomic number is always 7 no matter the
isotope.
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CRS Question, 2–19
QUESTION
40 2+
Ca has
20
1)
2)
3)
4)
5)
20 protons, 20 neutrons, and 18 electrons.
22 protons, 20 neutrons, and 20 electrons.
20 protons, 22 neutrons, and 18 electrons.
22 protons, 18 neutrons, and 18 electrons.
20 protons, 20 neutrons, and 22 electrons.
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CRS Question, 2–20
ANSWER
1)
20 protons, 20 neutrons, and 18 electrons.
Section 2.5 The Modern View of Atomic
Structure: An Introduction (p. 49)
The subscript is the number of protons. The
superscript is the number of protons plus
neutrons. Therefore the number of neutrons is
40 – 20. A neutral calcium atom has 20
electrons, but this is a +2 calcium ion, so it has
18.
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CRS Question, 2–21
QUESTION
All of the following are true except:
1) Ions are formed by adding electrons to a
neutral atom.
2) Ions are formed by changing the number of
protons in an atom’s nucleus.
3) Ions are formed by removing electrons from
a neutral atom.
4) An ion has a positive or negative charge.
5) Metals tend to form positive ions.
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CRS Question, 2–22
ANSWER
2)
Ions are formed by changing the number of
protons in an atom’s nucleus.
Section 2.6 Molecules and Ions (p. 52)
The removal of a proton from the nucleus
requires extraordinary amounts of energy. It will
only happen during a nuclear reaction.
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CRS Question, 2–23
QUESTION
Which among the following represent a set of
isotopes? Atomic nuclei containing:
a.
b.
c.
d.
e.
20 protons and 20 neutrons.
21 protons and 19 neutrons.
22 neutrons and 18 protons.
20 protons and 22 neutrons.
21 protons and 20 neutrons.
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CRS Question, 2–24
QUESTION (continued)
1)
2)
3)
4)
5)
a, b, c
c, d
a, e
a, d and b, e
No isotopes are indicated.
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CRS Question, 2–25
ANSWER
4)
a, d and b, e
Section 2.5 The Modern View of Atomic
Structure: An Introduction (p. 49)
Isotopes have the same number of protons and
different numbers of neutrons, so they can be
organized by atomic number.
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CRS Question, 2–26
QUESTION
By knowing the number of protons a neutral
atom has, you should be able to determine
1) the number of neutrons in the neutral atom.
2) the number of electrons in the neutral atom.
3) the name of the atom.
4) two of these.
5) none of these
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CRS Question, 2–27
ANSWER
4)
two of these.
Section 2.5 The Modern View of Atomic
Structure: An Introduction (p. 49)
The number of electrons in a neutral atom is the
same as the number of protons. The number of
protons (atomic number) allows you to name the
element by consulting the periodic table.
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CRS Question, 2–28
QUESTION
The average mass of a carbon atom is 12.011.
Assuming you were able to pick up only one
carbon unit, the chances that you would
randomly get one with a mass of 12.011 is
1) 0%.
2) 0.011%.
3) about 12%.
4) 12.011%.
5) greater than 50%.
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CRS Question, 2–29
ANSWER
1)
0%.
Section 3.1 Atomic Mass (p. 77)
The 12.011 is an average of the isotopic
masses. None of the isotopes has a mass of
12.011.
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CRS Question, 2–30
QUESTION
How many oxygen atoms are there in one
formula unit of Ca3(PO4)2?
1) 2
2) 4
3) 6
4) 8
5) None of these
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CRS Question, 2–31
ANSWER
4)
8
Section 2.8 Naming Simple Compounds (p. 57)
57
Remember to multiply the number of oxygen
atoms in the parentheses by the subscript
outside of the parentheses.
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CRS Question, 2–32
QUESTION
Which of the following are incorrectly paired?
1) Phosphorus, Pr
2) Palladium, Pd
3) Platinum, Pt
4) Lead, Pb
5) Potassium, K
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CRS Question, 2–33
ANSWER
1)
Phosphorus, Pr
Section 2.7 An Introduction to the Periodic Table
(p. 55)
Phosphorus has a symbol of P.
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CRS Question, 2–34
QUESTION
All of the following are characteristics of metals
except:
1) good conductors of heat.
2) malleable.
3) ductile.
4) often lustrous.
5) tend to gain electrons in chemical reactions.
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CRS Question, 2–35
ANSWER
5)
tend to gain electrons in chemical reactions.
Section 2.7 An Introduction to the Periodic Table
(p. 55)
Metals have a low electron affinity and tend to
lose electrons to nonmetals during the formation
of ionic compounds.
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CRS Question, 2–36
QUESTION
All of the following are characteristics of
nonmetals except:
1) poor conductors of electricity.
2) often bond to each other by forming
covalent bonds.
3) tend to form negative ions in chemical
reactions with metals.
4) appear in the upper left-hand corner of the
periodic table.
5) do not have a shiny (lustrous) appearance.
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CRS Question, 2–37
ANSWER
4)
appear in the upper left-hand corner of the
periodic table.
Section 2.7 An Introduction to the Periodic Table
(p. 55)
The nonmetals are found in the upper RIGHTHAND corner of the periodic table.
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CRS Question, 2–38
QUESTION
The correct name for LiCl is:
1) lithium monochloride.
2) lithium (I) chloride.
3) monolithium chloride.
4) lithium chloride.
5) monolithium monochloride.
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CRS Question, 2–39
ANSWER
4)
lithium chloride.
Section 2.8 Naming Simple Compounds (p. 57)
Lithium is a Group IA metal, so it always forms a
+1 ion. Therefore, no roman numeral is
necessary.
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CRS Question, 2–40
QUESTION
The correct name for FeO is:
1) iron oxide.
2) iron (II) oxide.
3) iron (III) oxide.
4) iron monoxide.
5) iron (I) oxide.
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CRS Question, 2–41
ANSWER
2)
iron (II) oxide.
Section 2.8 Naming Simple Compounds (p. 57)
Iron is a transition metal that forms more than
one type of ion. A roman numeral is needed to
indicate which ion is present in the compound.
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CRS Question, 2–42