Modified True/False
Indicate
whether the sentence or statement is true or false. If false, change the identified word or
phrase to make the sentence or statement true.
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1.
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A
change that produces one or more new substances is called a physical change.
_________________________
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2.
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The
freezing point of water is 100ºC. _________________________
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3.
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A
pure substance is made of only one kind of matter and has definite properties.
_________________________
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4.
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An
object’s mass is a measure of the force of gravity acting on the object.
_________________________
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5.
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The
density of a material is expressed as volume divided by mass.
_________________________
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6.
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The
smallest particle of an element is called an atom. _________________________
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7.
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In
the early 1800s, John Dalton proposed a theory including the idea that atoms cannot be broken
apart. _________________________
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8.
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A
molecule can contain just a few atoms or as many as a billion atoms.
_________________________
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9.
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Weight is a physical property that enables miners to distinguish between real
gold and “fool’s gold,” or pyrite. _________________________
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10.
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In
blast furnaces, iron metal separates from its ore because oxygen in the ore reacts with
carbon. _________________________
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Essay
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11.
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Suppose that a spacecraft from Earth lands on the moon and then returns to Earth.
Describe how the mass and weight of a person in the spacecraft would be affected while on Earth and
on the moon. Remember that the moon has the weaker force of gravity.
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12.
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Explain the difference between a mixture and a compound.
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13.
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Explain how you could find out whether or not an unknown liquid was
water.
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14.
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Describe Dalton’s theory of atoms.
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15.
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Explain the difference between atoms and molecules.
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16.
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When
an electric current is passed through water during the process of electrolysis, two gases are formed.
One gas has a boiling point of –183°C and the other has a boiling point of
–253°C. Was this event a physical change or a chemical change? Explain.
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17.
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Explain why panning, which can be used to obtain the element gold, cannot be used to
obtain the element iron.
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18.
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The
density of gold is 19.3 g/cm3. What does it mean to say that density is a characteristic
property of gold?
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