Unit 6, Chapter 2 Quiz
QUIZ
Name
Date
Class
Part I: Multiple Choice
1. The Ultrascope diagram represents the molecular structure
of solid water (ice). The chemical bonds in water are
Ultrascope
a) covalent.
b) metallic.
c) ionic.
d) cohesive.
2. The diagram at right shows the atoms of four water
molecules. What types of bonds do the black and white
springs represent?
a) The black springs represent covalent chemical bonds,
and the white springs represent cohesive bonds.
b) All springs represent covalent chemical bonds.
c) All springs represent cohesive bonds.
d) The white springs represent covalent chemical bonds,
and the black springs represent cohesive bonds.
3. What is the correct chemical formula for the molecule shown
in the Ultrascope?
Ultrascope
H
a) 2CH3
b) 2C3H
c) C2H6
H
H
C
C
H
H
H
d) C6H2
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ethane
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CHAPTER 2 CHEMICAL REACTIONS AND THE STRUCTURE OF MATERIALS
4. Hydrogen peroxide, H2O2, decomposes (breaks down) into water and oxygen gas. The
chemical equation for a reaction is 2 H2O2 ⇒ 2H2O + O2. Which of these drawings correctly
represents the reactant particles in a picture balanced equation? The smaller, lighter-colored
atoms are hydrogen (H), and the darker-colored atoms are oxygen (O).
a)
Ultrascope
b)
Ultrascope
c)
Ultrascope
d)
Ultrascope
5. One reaction that contributes to acid rain is the reaction between a nitrogen-oxygen compound
and water vapor. This reaction produces tiny droplets of nitrous acid and nitric acid. The
picture-balanced equation of this reaction is shown below. What is the correct way of writing
out just the left-hand side of the symbolic-balanced equation, showing the reactants?
Reactants
Products
water
(H2O)
nitrogen dioxide
(NO2)
nitrous acid
(HNO2)
nitric acid
(HNO3)
N
O
O
O
+
N
O
H
H
O
N
O
H
O
O
+
H
N
O
O
a) N2O4 + H2O
b) 2N2O + H2O
c) 2NO2 + H2O
6. In a chemical interaction, particles of the original substances collide and
a) the atoms combine to form completely new atoms.
b) the atoms bounce off of one another without breaking the chemical bonds to form
completely new particles.
c) the atoms recombine to form completely new particles.
d) the atoms break apart into smaller pieces containing protons and electrons, which then
combine to form completely new atoms.
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UNIT 6: INTERACTIONS AND THE STRUCTURE OF MATERIALS
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d) 2NO4 + H2O
Unit 6, Chapter 2 Quiz
7. The two Ultrascopes at right represent samples
of pure nitrogen and oxygen gases. Of these four
Ultrascope drawings below, which best represents
the products of a chemical reaction between
nitrogen and oxygen?
a)
Ultrascope
b)
Ultrascope
c)
Ultrascope
d)
Ultrascope
Ultrascope
Ultrascope
Nitrogen
Oxygen
8. Which sentence best describes the Ultrascope
representation of solid carbon dioxide (at a
very low temperature) shown to the right?
a) Molecules, each containing one carbon
atom covalently bonded to two oxygen
atoms, are held together by weak cohesion
attractions.
b) The carbon atoms have strong metallic bonds
with the oxygen atoms, so they have strong
cohesion attractions between the particles.
Ultrascope
O
C
O
carbon dioxide
c) Molecules are made up of a regular pattern of
positive carbon ions and negative
oxygen ions.
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d) Carbon atoms and covalently bonded oxygen molecules are held together by
weak cohesion attractions.
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CHAPTER 2 CHEMICAL REACTIONS AND THE STRUCTURE OF MATERIALS
9. Refer to the diagrams of four different Ultrascope models shown below. Which Ultrascope
model above represents metallic chemical bonds? Select answer A, B, C or D.
a)
Ultrascope
b)
Ultrascope
c)
Ultrascope
d)
Ultrascope
10. The stronger the attraction between atoms or ions,
a) the larger the size of the atoms or ions.
b) the smaller the size of the atoms or ions.
c) the greater the cohesion attractions between the molecules.
d) the greater the energy in their chemical bonds.
a) white only
b) black only
c) black and white
d) none of these
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UNIT 6: INTERACTIONS AND THE STRUCTURE OF MATERIALS
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11. The diagram below shows the atoms of four water molecules in liquid water. Which bond
energies (represented by black and white springs), when added together, make up the stored
chemical energy of the water?
Unit 6, Chapter 2 Quiz
12. In the rusting reaction, iron combines with oxygen to form rust. Suppose an iron nail is left
outside and rust forms on it. How would the mass of the rust and the nail after rusting
compare to the mass of the unrusted nail, and why?
a) The mass of the rust and nail is greater because oxygen atoms from the surrounding
air combined with iron atoms in the nail to form the rust.
b) The mass of the rust and nail is greater because the mass of the rust is added to the
original mass of the nail.
c) The mass of the rust and nail stays the same because no matter has been added to or
taken away from the iron nail to form rust.
d) The mass of the rust and nail is less because some of the iron was used up to produce
the rust, and the rust is less solid and has less mass than iron.
13. Which sentence best describes a balanced chemical equation?
a) The total number of molecules is the same in both the reactants and products.
b) The mass of each atom is the same before and after the chemical reaction.
c) The number of atoms of each element is the same in both the reactants and products.
d) The mass of all the atoms in the reactants is the same, and the mass of all the atoms in
the products is the same.
14. Refer to the balanced picture equation of the photosynthesis reaction below. The correct
balanced word equation is:
carbon dioxide (CO2)
water (H2O)
H
O
O
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O
C
O
C
O
O
O
C
O
O
C
O
O
C
O
oxygen (O2)
H
O
H
C
glucose (C6H12O6)
H
O
H
+
H
O
H
H
H
O
H
H
H
C
O H
C
H
H
O
O
O
O
H
O
O
O H
O
O
O
O
O
H
C
H
C
O
O
H
H C
H
O
O
O
H
H
C
O
+
O
a) 6 carbon dioxide molecules (CO2) + 6 water molecules (H2O) ⇒ 1 glucose molecule
(C6H12O6) + 6 oxygen molecules (O2)
b) 6 carbon dioxide atoms (CO2) + 6 water atoms (H2O) ⇒ 1 glucose molecule (C6H12O6)
+ 6 oxygen atoms (O2)
c) 6 carbon dioxide molecules (CO2) + 6 water molecules (H2O) ⇒ 6 glucose molecules
(C6H12O6) + 12 oxygen atoms (O2)
d) 6 carbon atoms (C) + 18 oxygen atoms (O) + 12 hydrogen atoms (H) ⇒ 1 glucose
molecule (C6H12O6) + 12 oxygen atoms (O)
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CHAPTER 2 CHEMICAL REACTIONS AND THE STRUCTURE OF MATERIALS
15. An incorrectly balanced picture equation for a chemical reaction is shown below. What
particles (atoms or molecules) would you have to add to correct the equation?
carbon
monoxide (CO)
O
oxygen (O2 )
carbon
dioxide (CO2 )
O O
O C O
C
+
O
C
a) One carbon dioxide molecule (CO2) needs to be added to the products.
b) One carbon atom (C) needs to be added to the products.
c) One oxygen molecule (O2) needs to be added to the products.
d) One carbon monoxide molecule (CO) needs to be added to the products.
16. One reason carbon atoms can form millions of compounds is because carbon atoms
a) can form ionic bonds with many other elements.
b) can form metallic bonds with other carbon atoms in long chains.
c) can form covalent bonds with other carbon atoms or atoms of other elements.
d) is the most abundant element found in the Earth’s crust.
17. Suppose one polymer chain is made from two monomers, and a second polymer chain is made
from the same two monomers. Which of the following statements is TRUE?
a) The two polymer chains may have different patterns.
b) The two polymer chains have the same pattern.
c) Both polymer chains have branches because polymers made from two monomers
always have branches.
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d) Neither polymer chain has branches because polymers made from two monomers
never have branches.
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UNIT 6: INTERACTIONS AND THE STRUCTURE OF MATERIALS
Unit 6, Chapter 2 Quiz
Part II: Picture Equations
When ethane gas (C2H6) is burned, it combines with oxygen gas (O2) in a reaction to make carbon
dioxide (CO2) and water (H2O). A picture equation for this chemical reaction is shown below.
Reactants
ethane (C2H6)
H
H
H C
C H
H H
Products
oxygen (O2)
O
+
O
O
water (H2O)
carbon dioxide (CO2)
H
O
O
C
O
O
C
O
+
O
H
O
O
H
H
O
H
H
O
Keeping Track
of the Atoms
REACTANTS
PRODUCTS
Number of ____ atoms:___
Number of ____ atoms:___
Number of ____ atoms:___
Total:
Number of ____ atoms:___
Number of ____ atoms:___
Number of ____ atoms:___
Total:
18. Is this picture equation balanced at the particle level? To answer that, follow the procedure in
How To Decide Whether a Picture Equation of a Chemical Interaction is Correct (Balanced)
and fill in the table under the picture equation. (Use steps A and B in the How To).
19. Complete the following sentence (use step C in the How To):
This picture equation (is / is not) _______________ balanced because _________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
Part III: Learning About Questions
20. The main role of water in plants and animals is to
a) dissolve other chemicals necessary for life.
b) provide an essential nutrient necessary for healthy cells.
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c) regulate the production of sulfur in the bloodstream.
d) control the production of vitamins.
21. What is a main function of proteins?
a) Proteins are the main energy source in the body.
b) Proteins dissolve other chemicals necessary for life.
c) Proteins provide the information needed to make cells.
d) Proteins make enzymes that control chemical reactions.
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CHAPTER 2 CHEMICAL REACTIONS AND THE STRUCTURE OF MATERIALS
22. Listed below are four statements about the chemical energy stored in fats. Choose the
statement that is NOT TRUE.
a) The body only uses fats for energy when the energy in glucose has been "used up."
b) Fats are good insulators against cold, so the energy in the fats can't be used until the
weather is warm.
c) Fats store twice as much energy as carbohydrates, so there is more energy to
"burn off."
d) Fats don't dissolve in water very well, so the energy in them can be stored a long time
without being "washed out."
23. What is the role of enzymes in the release of stored chemical energy in your body?
a) Enzymes dissolve fat molecules, allowing the energy stored in fat to be released.
b) Enzymes speed up chemical reactions in cells, causing energy to be released more
quickly.
c) Water dissolves enzymes and causes the stored energy in enzymes to be released.
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d) Enzymes have nothing to do with the release of stored energy in your body.
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UNIT 6: INTERACTIONS AND THE STRUCTURE OF MATERIALS