Quiz Review

1
Quiz Review

• Chemical Reactions and Physical Change

2
Identify each type of reaction.
3
Identify each type of reaction.
4
Decide if the equation is balanced.
5
Decide if the equation is balanced.
6
NaOH HCl NaCl H2O

• Identify the reactants.
• What is the 2 in H2O called? What does is
  mean?
• Which is an example of a chemical formula?
• OH-1 Cl HCl

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NaOH HCl NaCl H2O

• 1. Identify the reactants.
• NaOH HCl
• 2. What is the 2 in H2O called? What does is
  mean?
• A subscript tells how many atoms of a substance
  are in a molecule.
• 3. Which is an example of a chemical formula?
• OH (ion) Cl (element) HCl (chemical formula)

8
Know This

• Chemical bonds hold compounds and molecules
  together.
• Shared electrons are covalent bonds.
• Covalent molecules can be polar or nonpolar.
• Lost or gained electrons are ionic bonds.
• Positive ions lose electrons. Negative ions gain
  electrons.
• Metallic bonds are like a sea of electrons.

9
Answer the questions.

• How many valance electrons does this element
  have?
• What group does this element belong to?
• What is the name of this family?
• With how many atoms of an alkali metal will ths
  element bond?
• What type of bond will this element form with a
  metal?

10
Answer the questions.

• 7 valence electrons
• Group 17
• Halogen Family
• Halogens bond 11 with alkali metals.
• A metal and a nonmetal form an ionic bond.

11
Name that Bond
12
Name that Bond
Covalent bond Double bond Formed between a
nonmetal and nonmetal
13
Name that Bond
14
Name that Bond
Ionic bond Formed between a metal and
nonmetal Lithium fluoride
15
Name that Bond
16
Name that Bond
Covalent bond Polar covalent Formed between a
nonmetal with few protons and nonmetal with many
more protons
17
Name that Change

• Yeast added to peroxide foams and raises the
  temperature from 25OC to 45OC
• Name the type of change and evidence

18
Name that Change

• Chemical change
• A gas was released.
• There was a temperature change without adding
  heat energy.
• Yeast contains an enzyme that catalyzes the
  reaction.

• Yeast added to peroxide foams and raises the
  temperature from 25OC to 45OC
• Name the type of change and evidence

19
Name that Change

• Bubbles rise through water as it is heated on a
  hotplate and water vapor forms
• Name the type of change and evidence

20
Name that Change

• Bubbles rise through water as it is heated on a
  hotplate and water vapor forms
• Name the type of change and evidence

• Physical change
• When heat was added to the water, the air mixed
  into it separated out as bubbles.
• The water vapor was a phase change.

21
Name that Change

• Bubbles form when baking soda is added to vinegar
  and the temperature of the solution decreases.
• Name the type of change and evidence

22
Name that Change

• Bubbles form when baking soda is added to vinegar
  and the temperature of the solution decreases.
• Name the type of change and evidence

• Chemical change
• The baking soda underwent a chemical change and
  released carbon dioxide.
• The temperature decrease indicated that energy
  was absorbed by the reactants.

23
Name that Change

• When sodium chloride is placed in a flame it
  emits a yellow flame.
• Name the type of change and evidence

24
Name that Change

• When sodium chloride is placed in a flame it
  emits a yellow flame.
• Name the type of change and evidence

• Chemical change
• The electrons of the sodium were excited by the
  heat of the flame and light was emitted.
• The sodium was burned by the flame.

25
Faster or Slower?

• Powdered Alka Seltzer vs. a tablet of Alka
  Seltzer in the same temperature water
• Why?

26
Faster or Slower?

• Powdered Alka Seltzer vs. a tablet of Alka
  Seltzer in the same temperature water
• Why?

• Faster because increasing the surface area of a
  reactant increases the rate of reaction.

27
Faster or Slower?

• A tablet of Alka Seltzer in hot water vs. a
  tablet of Alka Seltzer in cold water
• Why?

28
Faster or Slower?

• A tablet of Alka Seltzer in hot water vs. a
  tablet of Alka Seltzer in cold water
• Why?

• Faster because increasing the temperature of
  reactants increases the rate of reaction.

29
Faster or Slower?

• Adding baking soda all at once to vinegar vs.
  adding baking soda a small amount at time to
  vinegar
• Why?

30
Faster or Slower?

• Adding baking soda all at once to vinegar vs.
  adding baking soda a small amount at a time to
  vinegar
• Why?

• Faster because increasing concentration of
  reactants increases the rate of reaction.