Download Finals Review ans 2012sem 1

Physical Science Final Review Answers
____
1.
Ninety-nine percent of all the matter that can be observed in the universe exists as plasmas.
____ 2.
Hydrochloric acid, HCl, is added to solid NaOH. After the reaction is complete, NaCl
dissolved in water remains. What are the products of this chemical reaction? NaCl and H2O
____ 3.
In an electron dot diagram, the symbol for an element is used to represent the nucleus and
all non-valence electrons
____ 4.
Which statement is true about the metalloid silicon? Silicon
is a better conductor of electric current than sulfur is.
____ 5.
In which of the substances in Figure 3-1 are the forces of attraction among the particles so
weak that they can be ignored under ordinary conditions? Substance C
____ 6.
number
____ 7.
To find the number of neutrons in an atom, you would subtract atomic number from mass
Which of the following is a heterogeneous mixture? a jar of mixed nuts
____ 8.
Boyle’s law states that the volume of a gas is inversely proportional to its pressure if the
temperature and number of particles are constant
____
9.
How many grams of CO2 are in 2.1 mol of the compound? 92.4 g
____
10.
The heat of fusion for water is the amount of energy needed for water to melt.
____ 11.
Raising the temperature of a gas will increase its pressure if the volume of the gas and the
number of particles are constant
____ 12.
What physical properties of nylon and leather make them good materials to use for
shoelaces? durability and flexibility
____ 13.
You see a structural formula in which the symbols for elements are connected by a long dash.
You can assume that the chemical bonds in the compound are covalent.
____
14.
Democritus thought that matter was made of tiny particles that were all round and smooth
____
15.
Which of the following Group 1A elements is the most reactive? Fr
____ 16.
How does increasing the amount of carbon in steel affect its properties? Carbon makes the
lattice harder and stronger.
____ 17. The phase change in which a substance changes from a solid to a liquid is melting.
____ 18.
Which statement about metals is true? Electrons in a metal lattice are free to move
____ 19.
Figure 5-1 shows a portion of a blank periodic table. Identify the segments labeled A and B A
is a period and B is a group.
____
20.
The standard on which the atomic mass unit is based is the mass of a carbon-12 atom
____ 21.
The water molecule H2O is polar because it contains two polar single bonds and its molecule
has a bent shape
____
22.
Which of the following Group 7A elements is the most reactive? F (fluorine)
____
23.
What is the difference between an atom in the ground state and an atom in an excited state?
The atom in an excited state has more energy and is less stable than the atom in the ground state.
____
24.
The unit for atomic mass is amu
____ 25.
Metallic bonding is similar to ionic bonding because there is an attraction between
positively charged and negatively charged particles.
____
26.
A substance that is made up of only one kind of atom is a(an) element.
____
27.
To keep them from reacting, some highly reactive elements are stored in argon.
____ 28.
For the chemical reaction C2H6 + 137 kJ  C2H4 + H2, the chemical energy of the products
is greater than the chemical energy of the reactant
____
29.
Which halogen is most likely to react? F (fluorine)
____
30.
The name iron(II) indicates that a compound contains iron ions with a 2+ charge.
____ 31.
same charge
Which statement about subatomic particles is NOT true? Protons and neutrons have the
____ 32.
The phase change in which a substance changes from a solid to a gas or vapor without
changing to a liquid first is sublimation.
____
33.
Group 7A of the periodic table contains the most reactive nonmetals
____
34.
What is the result of a force distributed over an area? pressure
____ 35. If a solid piece of naphthalene is heated and remains at 80°C until it is completely melted, you know that 80ºC
is the
freezing point of naphthalene.
melting point of naphthalene.
____ 36.
When magnesium carbonate, MgCO2, reacts with nitric acid, HNO3, magnesium nitrate and
carbonic acid form. Carbonic acid then breaks down into water and carbon dioxide. Which two types of
reactions take place in this process? double-replacement and decomposition
Figure 7-1
____ 37.
The reaction in Figure 7-1 shows the formation of ammonia from nitrogen and hydrogen in
the Haber process. What will be the effect on the equilibrium if the temperature is increased and some of the
ammonia is removed from the system? Any effect will depend on the amount of change of temperature
and concentration.
____ 38. Which of the following is a typical property of an ionic compound? tendency to shatter when struck
____
39.
As you move from left to right across a period, the number of valence electrons increases.
____
40.
____ 41.
freezing
Which element is found in nature only in compounds? sodium
During which phase change does the arrangement of water molecules become more orderly?
____ 42.
Which of the following is a clue of a chemical change? a gas forms when vinegar and
baking soda are mixed
____ 43. Moving from left to right across a row of the periodic table, which of the following values increases by
exactly one from element to element? atomic number
____ 44.
A substance has a melting point of 0ºC and a boiling point of 100ºC. The substance is most
likely water
____ 45.
Which of the following does NOT show the law of conservation of mass? 24 mL of Mg burn
in 32 mL O2 to produce 56 mL of MgO
____
46.
Atoms of the most reactive elements tend to have one or seven valence electrons
____
47.
Which of the following are pure substances? compounds
____ 48. Fluorine, F, forms a binary ionic compound with lithium, Li. What is the name of this compound? lithium
fluoride
____ 49.
The tendency of an element to react is closely related to the number of valence electrons in
atoms of the element.
____ 50.
an atom
In an atomic model that includes a nucleus, positive charge is concentrated in the center of
____ 51.
Which phrase best describes a metallic bond? the attraction between a metal cation and a
shared pool of electrons
____ 52.
The Greek philosopher Democritus coined what word for a tiny piece of matter that cannot be
divided? atom
____ 53.
In the compound MgCl2, the subscript 2 indicates that there are two chloride ions for each
magnesium ion
____ 54.
Which statement about subatomic particles is true? An electron has far less mass than
either a proton or neutron
____ 55.
is a gas.
If you move a substance from one container to another and its volume changes, the substance
____ 56.
Which of the following statements is true about what happens during a chemical reaction?
Bonds of the reactants are broken, and bonds of the products are formed
____ 57. Which element is found in most of the compounds in your body except for water? carbon
____
58.
What is the symbol for aluminum? Al
____ 59.
An industrial process makes calcium oxide by decomposing calcium carbonate. Which of the
following is NOT needed to calculate the mass of calcium oxide that can be produced from 4.7 kg of calcium
carbonate? the balanced chemical equation
____
60.
A mixture that appears to contain only one substance is a(an) homogeneous mixture
____
61.
Which of the following compounds does NOT contain molecules? NaCl
____ 62.
Which of the following formulas represents a compound whose molecules contain a triple
bond? NN____
63.
Which of the following has the highest viscosity? corn syrup
____ 64.
Which of the following will cause a decrease in gas pressure in a closed container? lowering
the temperature
____ 65.
conserves
Which of the following does NOT state what the arrow means in a chemical equation?
____
Which statement is true about oxygen-17 and oxygen-18? They are isotopes of oxygen
66.
____ 67.
Which of the following groups contain three elements with stable electron configurations?
helium, xenon, neon
____ 68.
Alkali metals, alkaline earth metals, and aluminum all form ions with positive charges equal
to the group number.
____ 69.
The coefficients in a balanced chemical equation always can express the ratio of moles of
reactants and products
____
70.
A gas has no definite shape or definite volume
____
71.
One twelfth the mass of a carbon-12 atom is used to define a(an) atomic mass unit.
____ 72.
Many metals can be drawn into thin wires without breaking because cations are still
surrounded by electrons when they shift their positions in the lattice
____
73.
Ionization energies tend to increase from left to right across a period
____ 74.
The reaction H2CO3 + H2O  H3O+ + HCO3– takes place in water. What happens to the
equilibrium when the pressure is increased? It does not change
____ 75.
Mendeleev gave the name eka-aluminum to a(an) unknown element he predicted would
have properties similar to those of aluminum
Figure 6-1
____ 76.
Study the electron dot diagrams for lithium, carbon, fluorine, and neon in Figure 6-1. Choose
the statement that correctly identifies the most stable of the elements. Neon is the most stable element
because its highest occupied energy level is filled.
____
77.
The formation of an ionic bond involves the transfer of electrons.
____ 78. Compared with Group 2A elements, Group 6A elements have more valence electrons
____ 79.
Two highly reactive elements in Period 2 are the metal lithium and the nonmetal fluorine
____
lost
80.
Which of the following takes place during a redox reaction? Electrons are both gained and
____ 81.
Which of the following is a balanced chemical equation for the synthesis of NaBr from Na
and Br2? 2Na + Br2  2NaBr
____
82.
During a phase change, the temperature of a substance does not change.
____ 83.
Which of the following provides the best analogy for an electron in an atomic orbital? a bee
trying to escape from a closed jar
____
84.
Flammability is a material’s ability to burn in the presence of oxygen.
____
85.
In general, if the temperature of a chemical reaction is increased, the reaction rate increases.
____
86.
Reaction rates do NOT tell you how fast substances are changing state.
____ 87.
Which statement about electrons and atomic orbitals is NOT true? An electron has the same
amount of energy in all orbitals.
____
88.
Which list of elements contains only metals? tin, copper, cesium
____ 89.
Which of the following is NOT part of John Dalton’s atomic theory? Atoms contain
subatomic particles.
____ 90. When a physical change in a sample occurs, which of the following does NOT change? Composition
____ 91. What type of change occurs when water changes from a solid to a liquid?
a phase change
a physical change
____ 92.
reactant
Which of the following is NOT always true about a synthesis reaction? There is only one
____ 93.
Methane, CH4, burns in oxygen gas to form water and carbon dioxide. What is the correct
balanced chemical equation for this reaction? CH4 + 2O2  2H2O + CO2
____ 94.
Suppose an atom has a mass number of 23. Which statement is true beyond any doubt? The
number of protons in the nucleus does not equal the number of neutrons
____
95.
Forces of attraction limit the motion of particles most in a solid.
____ 96. Which of the following is a physical change? sawing a piece of wood in half
____ 97.
Water has a higher boiling point than expected because of the strong attractions between
polar water molecules
____
98.
In a periodic table, a set of properties repeats from row to row.
____
99.
Matter that has a definite volume but no definite shape is a liquid.
____ 100.
You are about to open a container of soy milk but notice that there are instructions to “shake
well before serving.” The soy milk is most likely a solution.
Essay
101. Suppose you want to separate the leaves, acorns, and twigs from a pile of soil. Filtration and distillation are
two processes of separating mixtures. Explain which process you would use and why.
102. Fluorine is the most reactive nonmetal. To fluorine’s immediate right in the periodic table is neon, a noble gas
that does not form chemical bonds. Explain this contrast in reactivity in terms of atomic structure.
103. Explain why rust forms in steel tanks that hold seawater in ships. How can nitrogen be used to reduce rust in
these tanks?
104. In science lab, your teacher gives you two small pieces of matter and tells you that one piece is a metal and
one is a nonmetal. Without changing the size or shape of the pieces, how could you test them to determine
which is the metal?
105. A sample of calcium contains calcium-40, calcium-44, calcium-42, calcium-48, calcium-43, and calcium-46
atoms. Explain why these atoms can have different mass numbers but must have the same atomic number.
106. Describe how water can change from a liquid to a vapor at temperatures lower than its boiling point.
107. Why were the elements gallium (Ga), scandium (Sc), and germanium (Ge) important to Mendeleev?
ESSAY
101. ANS:
Filtration would be used because it is the process of separating mixtures based on the size of their particles (or
pieces). A screen could be used to separate the mixture. The holes in the screen would need to be large
enough to allow the soil to pass through but not the leaves, acorn, or twigs.
PTS: 1
DIF: L2
OBJ: 2.2.4
102. ANS:
The electron configuration of an element determines its reactivity. Fluorine, with seven valence electrons,
tends to gain one electron to fill its highest occupied energy level. Neon, with eight valence electrons, has a
stable electron configuration. Neon’s highest occupied energy level holds the maximum possible number of
electrons.
PTS: 1
DIF: L2
OBJ: 6.1.1
STA: 1.1.9-11.H.a
103. ANS:
Rust forms in the tanks because oxygen dissolved in the water reacts with iron in the steel. Nitrogen gas can
be pumped into the tanks. The nitrogen displaces some of the dissolved oxygen. Because nitrogen is less
reactive than oxygen, less rust forms.
PTS: 1
DIF: L2
OBJ: 2.3.1
STA: 1.1.9-11.A.b | 1.1.9-11.G.a | 1.1.9-11.G
104. ANS:
You could see which piece conducts an electric current or which piece is a better conductor of heat.
PTS: 1
DIF: L2
OBJ: 5.2.3
STA: 1.1.9-11.A.d | 1.1.9-11.F.b
105. ANS:
All the atoms of an element have the same atomic number because the atomic number equals the number of
protons in an atom. If one of the atoms had a different number of protons, the atom would not be a calcium
atom. The mass number can vary because it is the sum of the protons and neutrons, and isotopes of an element
can have different numbers of neutrons.
PTS: 1
DIF: L2
OBJ: 4.2.2
STA: 1.1.9-11.E.c | 1.1.9-11.E.b
106. ANS:
Water can evaporate at temperatures lower than its boiling point. Evaporation can take place at the surface of
water because some water molecules are moving fast enough to escape the liquid and vaporize. The higher the
temperature is, the faster the water molecules move, on average, and the faster evaporation takes place.
PTS: 1
DIF: L2
OBJ: 3.3.4
STA: 1.1.9-11.D.a | 1.1.9-11.D.b | 1.1.9-11.D
107. ANS:
Mendeleev predicted the properties of these undiscovered elements from data in his periodic table. When the
elements were discovered, their actual properties were found to be a close match to those Mendeleev had
predicted. Their discovery provided evidence of the usefulness of Mendeleev’s periodic table.
PTS: 1
DIF: L1
OBJ: 5.1.2