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Ch 3 Review
Indicate the answer choice that best completes the statement or answers the question.
1. Which of the following bonds is polar?
a. F—F
b. O—H
c. O—O
d. H—H
2. In the compound, H2O, the electrons in the bonds are unequally shared between oxygen and hydrogen, forming ____.
a. cations
b. ionic bonds
c. nonpolar molecules
d. polar bonds
3. Which statement proves that a chemical reaction has occurred?
a. Bubbles form in a liquid.
b. At least one substance changes color.
c. Substances with new chemical properties are formed.
4. Zinc combines with hydrochloric acid, the zinc replaces hydrogen. The chemical equation for this reaction
looks like: Zn + 2HCl  ZnCl2 + H2
This is a _____ reaction
a. synthesis
c. single-replacement
b. decomposition
d. double-replacement
5. Which activity is a type of combustion reaction?
a. burning wood
b. breaking down water
c. formation of table salt
6. In a chemical reaction, energy is released _____.
a. only when bonds are broken
b. only when bonds are formed
c. when bonds break and when bonds form
7. In the chemical formula H2O, how many atoms of oxygen are represented?
a. one
b. two
c. three
8. A change in _____ is a sign of energy being used in a chemical reaction.
a. temperature
b. color
c. odor
d. texture
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9. Ethanol has six hydrogen atoms, two carbon atoms, and one oxygen atom. Which is the correct chemical formula of the
model below?
a. C2H6O
b. 2CH6O
c. 6HCO
d. C26HO
10. Which of the following elements will likely form a negative ion in its ionic compounds?
a. Li, lithium
b. Al, aluminum
c. Mg, magnesium
d. Cl, chlorine
11. Metallic compounds _____.
a. are poor conductors of electricity
c. have low melting points
b. dissolve in water
d. can be hammered into sheets
12. Which pair of reactions are considered to be opposites?
a. synthesis and decomposition
b. single-replacement and synthesis
c. decomposition and double-replacement
d. single-replacement and double-replacement
13. If the arrangement of atoms in a substance changes, then which of the following is true?
a. A chemical reaction has occurred.
b. The physical state of the substance changes.
c. The chemical properties of the substance stay the same but the physical properties change.
d. The physical properties of the substance stay the same but the chemical properties change.
14. A reaction that has one reactant can only be a _____.
a. synthesis reaction
b. decomposition reaction
c. single-replacement reaction
d. double-replacement reaction
15. Atoms rearrange when _____.
a. chemical bonds break
b. particles collide with enough energy
c. neither a nor b
d. both a and b
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Ch 3 Review
16. Sodium fluoride and silver nitrate become sodium nitrate and silver chloride. Carbonate and hydrogen ions
become water and carbon dioxide. This is a _____ reaction.
a. synthesis
b. decomposition
c. single-replacement
d. double-replacement
17. According to the law of conservation of mass, how does the mass of the products in a chemical reaction compare to
the mass of the reactants?
a. There is no relationship.
b. The mass of products is sometimes greater.
c. The mass of reactants is greater.
d. The masses are always equal.
18. What has happened to the water in the illustration?
a. The bonds between the water molecules have broken, and the water turned to water vapor.
b. The water molecules spread out, and water is turned to water vapor.
c. The bonds between the atoms of the water molecule have broken, and the water turned to water vapor.
d. The bonds between the atoms of the water molecule have broken, and instead of water, there is now hydrogen
and oxygen.
19. Sodium is an atom represented as Na+. What does the “+” represent?
a. The plus sign means it can combine with almost every element found on the periodic table.
b. Sodium has a tendency to lose a valence electron when it becomes an ion.
c. Sodium has a tendency to gain a valence electron when it becomes an ion.
d. One positive sign is listed because it only takes one electron to make the atom neutral.
20. Which equation is balanced?
a. H2 + O2  H2O
b. 2Na + Cl2  2NaCl
c. CH4 + 2O2  CO2 + H2O
21. A single-replacement reaction has _____.
a. one reactant and one product
b. one reactant and two products
c. two reactants and one product
d. two reactants and two products
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22. Why is the following image representative of a polar molecule?
a. The electrons are located at the poles of the molecule chain.
b. The valence electrons are shared equally.
c. The molecule has an overall positive change.
d. The valence electrons are shared unequally.
Use the symbols representing types of reactions to answer the following questions.
I
II
III
IV
23. Which figure models a synthesis reaction?
a. I
b. II
c. III
d. IV
24. Which of the following compounds is NOT likely to have ionic bonds?
a. LiF
b. NaCl
c. CH4
d. MgF2
25. Which situation does NOT occur during chemical reactions?
a. Bonds are broken.
b. Atoms are created.
c. Compounds are formed.
26. Aspartame is an artificial sweetener; its formula is C13H16N2O5. Which element in the formula has the greatest
number of atoms?
a. carbon
b. hydrogen
c. nitrogen
d. oxygen
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27. Which situation does NOT occur during chemical reactions?
a. Bonds are broken.
b. Bonds are formed.
c. Mass is conserved.
d. Atoms are destroyed.
28. The maximum number of electrons in the second energy level of an atom is ____.
a. two
b. four
c. eight
d. ten
29. Which of the following is NOT a result of a chemical reaction?
a. bubbles in boiling water
b. a solid forming from two liquids reacting
c. copper turning green when exposed to air
d. the light given off by a firefly
30. A chemical bond that occurs when atoms share electrons is a(n) ____ bond.
a. covalent
b. ionic
c. magnetic
d. polyatomic
31. Which of the following is a compound?
a. gold
b. oxygen
c. neon
d. water
32. The _____ determines the mass of the products of a chemical reaction.
a. mass of the reactants
b. rate at which the reaction occurs
c. number of different products and reactants
d. amount of energy absorbed or released by the reaction
33. Which type of molecular model is represented in this image?
a. dot diagram
c. ball-and-stick model
b. structural formula
d. space-filling model
34. Which type of reaction is the opposite of a synthesis reaction?
a. decomposition
b. single-replacement
c. double-replacement
35. One property of an ionic bond is _____.
a. the formation of a shiny surface
b. the formation of solid crystals
c. low melting points
d. not dissolving in water
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36. An ion is an atom that has gained or lost _____.
a. electrons
b. protons
c. neutrons
d. metals
37. Which situation involves a chemical change?
a. food rotting
b. paper ripping
c. water freezing
Use the symbols representing types of reactions to answer the following questions.
I
II
III
IV
38. Which figure models a double-replacement reaction?
a. I
b. II
c. III
d. IV
39. The atoms in the products of a chemical reaction _____.
a. were present in the reactants
b. did not exist before the reaction
c. were created using energy from the reaction
40. In carbon dioxide, each oxygen atom shares four electrons with the carbon atom. What is this type of bond called?
a. triple covalent
b. double covalent
c. polar covalent
d. ionic
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Answer Key
1. b
2. d
3. c
4. c
5. a
6. b
7. a
8. a
9. a
10. d
11. d
12. a
13. a
14. b
15. d
16. d
17. d
18. d
19. b
20. b
21. d
22. d
23. b
24. c
25. b
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26. b
27. d
28. c
29. a
30. a
31. d
32. a
33. b
34. a
35. b
36. a
37. a
38. a
39. a
40. b
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