Changes in Matter
Guided Reading and Study
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Sample effects:
One or more new substances are produced.
Energy is either absorbed or released.
1.Any change that changes the form or
appearance of matter but does not make any
substance in the matter into a different substance
2.false
3.a, c, d
4.A chemical change is a change in matter
that produces one or more new substances.
5.Unlike a physical change, a chemical
change produces new substances with properties
different from those of the original substances.
6.c, d
7.law of conservation of mass
8.energy
9.true
10.Temperature is the average energy of
motion of the particles in matter. Thermal
energy is the total energy of all the particles in
an object.
11.a.exothermic b.endothermic
Observing Chemical Change
Guided Reading and Study
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Sample questions and answers:
Question What are physical properties of matter?
Answer Physical properties are characteristics
that can be observed without changing one
substance into another.
Question What is the evidence for chemical
reactions?
Answer The evidence for chemical reactions is
the formation of new substances and changes in
energy.
1. Matter is anything that has mass and takes
up space.
2. chemistry
3. a. Physical
b. Only by changing one substance into
another
4. False
5. a, b, d
6. chemical reaction, or chemical change
7. They break and form new bonds, producing
new substances.
8. Formation of new substances and changes
in energy
9. The change in color is an indication of a
change in properties, and a change in properties
is a sign that a chemical reaction occurred.
10. precipitate
11. It might indicate a chemical reaction,
because the bubbles are gas, and the presence of
a gas indicates a new substance may have been
formed.
12. True
13. A change in temperature reflects a change
in energy.
14. False
15. a. Energy is absorbed
b. Exothermic
Controlling Chemical Reactions
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a. Increase in surface area
b. Increase in temperature
c. Increase in concentration
d. Use of a catalyst
1. activation energy
2. True
3. The activation energy can be a spark.
4. Exothermic reaction
5. Endothermic reaction
6. For the reaction to start, a tiny amount of
activation energy is needed. Once a few molecules
react, the rest will quickly follow because
the first few reactions provide activation energy
for more molecules to react.
7. The energy of the products is greater than
the energy of the reactants.
8. Endothermic
9. The peak of the curve
Describing Acids and Bases
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Sample answers:
Q. What is an acid?
A. An acid is a substance that tastes sour, reacts
with metals and carbonates, and turns blue litmus
paper red.
Q. What is a base?
A. A base is a substance that tastes bitter, feels
slippery, and turns red litmus paper blue.
Q. What are uses of acids and bases?
A. Uses of acids include cleaning products,
fertilizers,
and car batteries; uses of bases include
cleaning products, baking ingredients, and
cement manufacturing.
1. It tastes sour. It reacts with metals and carbonates.
It turns blue litmus paper red.
2. Scientists never taste chemicals in order to
identify them. Many acids are not safe to eat.
3. Acids eat away at other materials.
4. Carbon dioxide gas forms.
5. indicator
6. It turns blue litmus paper red because
lemon juice is acidic.
7. It tastes bitter. It feels slippery. It turns red
litmus paper blue.
8. false
9. true
10. home; industry
11. acids
Acids and Bases in Solution
Guided Reading and Study
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Sample questions and answers:
Q. What is a neutral solution?
A. A neutral solution is one that has a pH
close to 7.
Q. What is neutralization?
A. Neutralization is a reaction between an acid
and a base.
1. A hydrogen ion is an atom of hydrogen that
has lost its electron.
2. hydrogen ions and negative ions
3. acid
4. A hydroxide ion is a negative ion made of
oxygen and hydrogen.
5. base
6. a, c
7. The pH scale is a range of values from 0 to
14. It express the concentration of hydrogen ions
in a solution.
8. Milk: about 6.5; soap: 10; water: 7;
vinegar: about 2.8; lemon: about 2.2; ammonia:
about 11.5
9. false
10. high
11. a, b