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1
Many chemical reactions occur around the home.
Describe one chemical reaction that occurs in
a home and the products of the reaction.
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• A chemical reaction that occurs around the home
  is the burning of charcoal for barbecues. When
  charcoal burns, it reacts with oxygen to form
  ash, carbon dioxide, and heat.
• The cooking of food is another example.

3
Copper sulfate, when dissolved in water, has a
blue color. When steel wool is mixed with a
copper sulfate solution, the steel wool
disappears, a brownish solid forms, and the color
of the solution changes from blue to green.
Explain how three changes that occur in this
experiment suggest a new substance may have been
formed.
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• The disappearance of the steel wool suggests that
  a new substance is forming. As steel does not
  dissolve in water, it is likely that it was part
  of the reaction that formed a new substance.
  Another new substance, the brown solid, was
  observed forming. Because it is different in
  color from the other substances, it is also
  probably a new substance. The color change of the
  solution from blue to green implies that a
  chemical change has taken place.

5
List the four signs of a chemical reaction
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• Formation of a gas
• Formation of a precipitate (solid in a liquid)
• Color change
• Energy change

7
Describe the difference between ionic and
covalent bonding.
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• Ionic bonding is the gaining or losing of
  electrons in atoms to make happy atoms.
• Covalent bonding is the sharing of electrons
  between atoms to make happy atoms.

9
What happens to atoms during a chemical reaction?
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• Chemical reactions occur when different atoms and
  molecules combine together and spit apart.
• Atoms are re-arranged in the way they are
  connected (or bonded) they are not created or
  destroyed.

11
Explain the difference between chemical and
physical changes.
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• PHYSICAL REACTION is a change that affects the
  size, shape or color of a substance but does not
  affect its composition no new substance is
  formed
• Examples might by melting, boiling, cutting,
  etc.
• CHEMICAL REACTION is a change caused by the
  rearrangement of the atoms of one or more
  substances, resulting in the formation of new
  substances, having entirely different properties.

13
State the Law of Conservation of Mass
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• Matter cannot be created or destroyed in an
  ordinary chemical reaction.

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Describe endothermic and exothermic
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• Endothermic absorbing energy
• Exothermic releasing energy

17
A student wrote the following equation4Al
3O2 2Al2O3 Write a sentence to describe what
occurs in this reaction.
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• In this reaction, aluminum reacts with oxygen to
  form Al2O3.

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Students carry out a chemical reaction by mixing
two solutions in a glass beaker. A temperature
probe in the beaker records changes in
temperature that occur after mixing. Within
seconds after mixing, the temperature rises from
25 C to 40 C. Then the temperature returns to
25 C over a period of several minutes.Based
on this data, what should be concluded about the
type of chemical reaction that has occurred?
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• The best conclusion is that an exothermic
  reaction has occurred. The students observe the
  temperature rising by 15 C soon after they mix
  the chemicals. This shows that the reaction has
  given off energy as heat. Although there is
  cooling afterward, that is normal. Any hot object
  cools as it gives off heat.

21
Betsy mixes and stirs two chemical solids
together. While stirring she notices that the
beaker is getting hot. What is happening to the
beaker?
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• The reaction of the two chemicals is releasing
  heat an EXOTHERMIC reaction