Elements, Compounds, and Mixtures

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Elements, Compounds, and Mixtures
Chapter 4
Preview
CRCT Preparation
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CRCT Preparation
Chapter 4
1. Which two substances in the table are most
likely the same? A substances A and
C B substances B and D C substances C and
D D substances A and D
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CRCT Preparation
Chapter 4
1. Which two substances in the table are most
likely the same? A substances A and
C B substances B and D C substances C and
D D substances A and D
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CRCT Preparation
Chapter 4
2. You are given two jars, each of which contains
an unknown substance. You are asked to determine
if the substances are different from one another
or if each jar contains the same substance. What
should you do to complete this task? A Compare
the appearances of the substances. If the
substances look the same, then they are the
same. B Compare only the physical properties of
the substances. If the substances have the same
density or melting point, then they are the
same. C Compare both the physical and the
chemical properties of the substances. If the
substances perform the same in a variety of
tests, then they are the same. D Compare the
physical states of the substances. If the
substances are in the same state, then they are
the same.
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CRCT Preparation
Chapter 4
2. You are given two jars, each of which contains
an unknown substance. You are asked to determine
if the substances are different from one another
or if each jar contains the same substance. What
should you do to complete this task? A Compare
the appearances of the substances. If the
substances look the same, then they are the
same. B Compare only the physical properties of
the substances. If the substances have the same
density or melting point, then they are the
same. C Compare both the physical and the
chemical properties of the substances. If the
substances perform the same in a variety of
tests, then they are the same. D Compare the
physical states of the substances. If the
substances are in the same state, then they are
the same.
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CRCT Preparation
Chapter 4
3. If two poisonous elements are combined
chemically, which of the following will be true
of the resulting compound? A The compound will be
more poisonous than the gases. B The compound
will be as poisonous as the gases. C The compound
may or may not be poisonous. D The compound will
not be poisonous.
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CRCT Preparation
Chapter 4
3. If two poisonous elements are combined
chemically, which of the following will be true
of the resulting compound? A The compound will be
more poisonous than the gases. B The compound
will be as poisonous as the gases. C The compound
may or may not be poisonous. D The compound will
not be poisonous.
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CRCT Preparation
Chapter 4
4. Ellen made the illustration to show one of the
steps in her most recent experiment. Which
statement describes what Ellen was doing during
this step of the experiment?
A She was using a chemical change to break down
a compound into the elements that make it up. B
She was using a physical change to separate the
compounds that make up an element. C She was
using a physical change to separate the
components that make up a mixture. D She was
using a chemical change to combine elements to
form a compound.
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CRCT Preparation
Chapter 4
4. Ellen made the illustration to show one of the
steps in her most recent experiment. Which
statement describes what Ellen was doing during
this step of the experiment?
A She was using a chemical change to break down
a compound into the elements that make it up. B
She was using a physical change to separate the
compounds that make up an element. C She was
using a physical change to separate the
components that make up a mixture. D She was
using a chemical change to combine elements to
form a compound.
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CRCT Preparation
Chapter 4
5. The graph was constructed from data collected
during a laboratory investigation. Which of the
following values is the amount of sodium nitrate
that can dissolve in 100 mL of water at 40C? A 0
g B 40 g C 100 g D 130 g
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CRCT Preparation
Chapter 4
5. The graph was constructed from data collected
during a laboratory investigation. Which of the
following values is the amount of sodium nitrate
that can dissolve in 100 mL of water at 40C? A 0
g B 40 g C 100 g D 130 g
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CRCT Preparation
Chapter 4
6. Ka-wai makes a solution which contains the
maximum amount of sodium chlorate that can
dissolve in 100 mL of water at 0C. He heats the
solution to 60C. How much additional sodium
chlorate must he add to once again have a
solution that has the maximum amount of sodium
chlorate dissolved in it at this new
temperature? A 2 g B 40 g C 50 g D 80 g
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CRCT Preparation
Chapter 4
6. Ka-wai makes a solution which contains the
maximum amount of sodium chlorate that can
dissolve in 100 mL of water at 0C. He heats the
solution to 60C. How much additional sodium
chlorate must he add to once again have a
solution that has the maximum amount of sodium
chlorate dissolved in it at this new
temperature? A 2 g B 40 g C 50 g D 80 g
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CRCT Preparation
Chapter 4
7. Which of the following sentences best
describes table salt, NaCl? A Table salt is a
compound made from two elements. B Table salt is
a mixture made from two elements. C Table salt is
an element made from two mixtures. D Table salt
is an alloy made from a metal and a nonmetal.
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CRCT Preparation
Chapter 4
7. Which of the following sentences best
describes table salt, NaCl? A Table salt is a
compound made from two elements. B Table salt is
a mixture made from two elements. C Table salt is
an element made from two mixtures. D Table salt
is an alloy made from a metal and a nonmetal.
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CRCT Preparation
Chapter 4
8. Imagine that you were asked to classify four
samples of equal and known volume, each of which
was made up of a single element. Which factor
would be most useful for identifying
them? A mass B shape C hardness D original source
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CRCT Preparation
Chapter 4
8. Imagine that you were asked to classify four
samples of equal and known volume, each of which
was made up of a single element. Which factor
would be most useful for identifying
them? A mass B shape C hardness D original source
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CRCT Preparation
Chapter 4
9. Rafiq has a container filled with a clear
liquid. He knows that the liquid is either a
compound or a mixture but does not know which.
What can Rafiq do to find out? Explain your
answer.
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CRCT Preparation
Chapter 4
9. Answer - Full credit answers should include
the following points Mixtures can be separated
by physical means but compounds cannot. Rafiq
should try to separate the liquid into different
substances by physical means, such as
distillation, centrifuging, or evaporation. If
Rafiq can separate the liquid into different
substances by physical means, it is a mixture.
If Rafiq cannot separate the liquid into
different substances by physical means, it is
probably a compound.
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CRCT Preparation
Chapter 4
10. Compare elements and compounds. How are they
similar and how are they different? List two
examples of each kind of substance.
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CRCT Preparation
Chapter 4
10. Answer - Full credit answers should include
the following points Both elements and
compounds are pure substances, which means that
they are substances in which there is only one
type of particle. An element is a pure
substance that cannot be separated into simpler
substances. A compound is a pure substance that
is composed of two or more elements that are
chemically combined. Com-pounds can be separated
into simpler substances by chemical means.
Students should give two examples of elements,
such as carbon, oxygen, or gold, and two examples
of compounds, such as water, carbon dioxide, or
table salt.