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1. What is a scientific theory?
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A) It is a collection of experimental data.
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B) It is an assertion of scientific fact.
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C) It is a guess or conjecture about natural phenomena.
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D) It is a fundamental relationship of nature.
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E) It is an explanation of natural phenomena that has undergone significant testing.
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ANS: E PTS: 1gg gg DIF: easy REF: 1.2
OBJ: Understand how the scientific method is an approach to performing science. gg gg gg gg gg gg gg gg gg gg
TOP: general concepts | scientific method MSC: general chemistry
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2. An untested explanation of a series of experimental observations is called
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A) a hypothesis gg
B) a theory gg
C) a law gg
D) an experiment gg
E) the scientific method gg gg
ANS: A PTS: 1 gg gg DIF: easy REF: 1.2
OBJ: Understand how the scientific method is an approach to performing gg gg gg gg gg gg gg gg gg
science. TOP:
gg general concepts | scientific method
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3. Which of the following statements concerning experiment and explanation is/are true?
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1. A law is always given in the form of a mathematical expression.
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2. Once a hypothesis passes one or two tests it is considered a theory.
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3. Observation is a key component of the scientific method.gg gg gg gg gg gg gg gg
A) 1 only gg
B) 2 only gg
C) 3 only gg
D) 1 and 2 gg gg
E) 1, 2, and 3
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ANS: C PTS: 1 gg gg DIF: easy REF: 1.2
OBJ: Understand how the scientific method is an approach to performing gg gg gg gg gg gg gg gg gg
science. TOP:
gg general concepts | scientific method
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4. A saline solution similar to that used for intravenous drips is made by dissolving 0.45
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g sodium chloride in 50.00 g water.
gg gg Which of the following statements concerning
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the saline solution and the law of conservation of mass is/are correct?
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1. The mass of the saline solution is greater than the mass of water.
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2. The mass of the saline solution is equal to the combined mass of
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sodium chloride and water.
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3. The mass of the saline solution is greater than the mass of the
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sodium chloride.
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, A) 1 only
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B) 2 only
gg
C) 3 only
gg
D) 1 and 2
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E) 1, 2, and 3
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ANS: D PTS: 1
gg gg DIF: easy REF: 1.3
OBJ: Apply the law of the conservation of gg gg gg gg gg gg
mass. TOP: general concepts | matter
gg gg gg gg gg
5. A 19.0-g sample of lithium is completely burned in air to form lithium oxide. The
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mass of lithium oxide must be
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A) less than 19.0 g. gg gg gg
B) greater than 19.0 g. gg gg gg
C) equal to 19.0 g. gg gg gg
D) all of the above. gg gg gg
E) none of the above. gg gg gg
ANS: B PTS: 1
gg gg DIF: easy REF: 1.3
OBJ: Apply the law of the conservation of mass. (Example gg gg gg gg gg gg gg gg
1.1) TOP: general concepts | matter
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6. A sample of silicon is burned in oxygen to form silicon dioxide.
gg gg gg What mass of gg gg gg gg gg gg gg gg gg gg
oxygen is consumed if 57.76 g silicon dioxide is formed from 27.00 g silicon?
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A) 30.76 g gg
B) 84.76 g gg
C) 1559.59 g gg
D) 0.47 g gg
E) none of the above. gg gg gg
ANS: A PTS: 1
gg gg DIF: easy REF: 1.3
OBJ: Apply the law of the conservation of gg gg gg gg gg gg
mass. TOP: general concepts | matter
gg gg gg gg gg
7. In a certain chemical reaction, 7.29 g of compound A is added to 5.70 g of
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compound B. Once the reaction is complete, 3.60 g of compound A and 1.17 g of
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compound B remain. What mass of products was produced?
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A) 17.76 g gg
B) 4.53 g gg
C) 8.22 g gg
D) 3.69 g gg
E) 4.77 g gg
ANS: C PTS: 1
gg gg DIF: easy REF: 1.3
OBJ: Apply the law of the conservation of mass. (Example 1.1)gg gg gg gg gg gg gg gg gg
TOP: general concepts | matter KEY: Law of Conservation of gg gg gg g g gg gg gg
Mass MSC: general chemistry
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8. A 5.77 g sample of calcium carbonate completely decomposes into calcium oxide (lime)
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and carbon dioxide gas when heated.
gg gg If 3.23 g calcium oxide is produced, what
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mass of carbon dioxide must have been formed?
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, A) 2.54 g gg
B) 9.00 g gg
C) 18.65 g gg
D) 0.56 g gg
E) 1.92 g gg
ANS: A PTS: 1
gg gg DIF: easy REF: 1.3
OBJ: Apply the law of the conservation of gg gg gg gg gg gg
mass. TOP: general concepts | matter
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9. A sample of rubidium carbonate, weighing 7.00 g, requires 2.20 g of hydrogen
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chloride gas to completely decompose to water, rubidium chloride, and carbon dioxide
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gas.
gg The total gg
mass of water and rubidium chloride formed is 7.90 g and no hydrogen chloride or
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rubidium carbonate remains. According to the law of conservation of mass, what
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mass of carbon dioxide must have been formed?
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A) 1.30 g gg
B) 0.90 g gg
C) 8.65 g gg
D) 17.10 g gg
E) 3.07 g gg
ANS: A PTS: 1
gg gg DIF: moderate REF: 1.3
OBJ: Apply the law of the conservation of gg gg gg gg gg gg
mass. TOP: general concepts | matter
gg gg gg gg gg
10. Sodium oxide reacts with water to produce sodium hydroxide. Suppose 18.6 g of
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sodium oxide is combined with 33.7 g of water.
gg gg When the reaction is complete,
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all the sodium oxide has been consumed. According to the law of conservation of
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mass, which is a true statement?
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A) The mass of sodium hydroxide produced must equal 52.3 g.
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B) The mass of unreacted water must equal 15.1 g.
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C) The mass of sodium hydroxide produced must equal 18.6 g.
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D) The mass of water consumed must equal 18.6 g.
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E) The mass of sodium hydroxide produced plus the mass of unreacted water
gg gg gg gg gg gg gg gg gg gg gg
must equal 52.3 g.
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ANS: E PTS: 1g g DIF: difficult REF: 1.3
OBJ: Apply the law of the conservation of mass. (Example 1.1)
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TOP: general concepts | matter KEY: Law of Conservation of
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Mass MSC: general chemistry
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11. After a certain chemical reaction has completed, it is found that 33.7 g of product
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was produced. According to the law of conservation of mass, which statement
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must be true?
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A) The total mass consumed of all reactants was 33.7 g.
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B) The mass consumed of each reactant was 33.7 g.
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C) The mass of reactants consumed depends on the number of reactants present.
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D) Before the reaction started, there was 33.7 g total of all reactants.
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E) Before the reaction started, there was 33.7 g of each reactant.
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ANS: A PTS: 1 g g DIF: difficult REF: 1.3
OBJ: Apply the law of the conservation of mass. (Example 1.1)
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