Mrs. Lee – 8th Grade Physical Science
Page 1
Chapter 8 Practice Test – Answer Key
______ b
1) A chemical bond is ______.
a) a way of organizing elements in the periodic table
b) the force that holds two atoms together
c) how elements react with each other
d) a result of combustion
______ a
2) The ways in which an atom can bond with other atoms depends on the atom’s
______.
a) valence electrons b) nucleus
c) atomic number
d) atomic mass
______ c
3) The most loosely held electrons in an atom are ______.
a) unstable electrons
b) covalent electrons
c) valence electrons
d) low-energy electrons
______ d
4) The maximum number of bonds a carbon atom can form is ______.
a) one
b) two
c) three
d) four
______ c
5) Many organic compounds ______.
a) have high melting points
b) have high boiling points
c) do not dissolve well in water
d) conduct electricity
______ a
6) The monomers of complex carbohydrates are ______.
a) simple sugars
b) amino acids
c) fatty acids
d) glycerol
______ b
7) Pure carbon exists as all the following forms EXCEPT ______.
a) graphite
b) methane
c) fullerene d) diamond
______ d
8) Carbohydrates are made up of carbon, hydrogen, and ______.
a) sulfur
b) nitrogen
c) phosphorus
d) oxygen
______ a
9) The names of saturated hydrocarbons end in ______.
a) –ane
b) –ine
c) –ene
d) –yne
______ c
10) Substituted hydrocarbons include all of the following EXCEPT ______.
a) alcohols
b) halogen-containing compounds
c) minerals
d) organic acids
______ a
11) Which of the following is a natural composite?
a) wood
b) fiberglass c) cellulose d) nylon
______ c
12) The main classes of organic compounds in living things include all of the
following EXCEPT ______.
a) carbohydrates
b) proteins
c) alcohols
d) lipids
______ a
13) Carbon atoms can form straight chains, branched chains, and rings.
a) True
b) False
Ch 8 Practice Test – Answer Key
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Mrs. Lee – 8th Grade Physical Science
Page 2
Chapter 8 Practice Test – Answer Key
______ b (esters)
14) Many fullerenes have pleasant, fruity smells.
a) True
b) False
______ a
15) Along with carbohydrates, lipids, and proteins, vitamins and minerals are other
nutrients that contribute to a healthy diet.
a) True
b) False
______ b (hydroxyl group) 16) A combination of an oxygen atom and a hydrogen atom, -OH, is
called a hydrocarbon.
a) True
b) False
______ b (Proteins) 17) Nucleotides are polymers made of amino acids.
a) True
b) False
______ b (saturated) 18) A hydrocarbon with only single bonds in its carbon chain is called an
unsaturated hydrocarbon.
a) True
b) False
______ a
19) Fats and oils are energy-rich organic compounds called lipids.
a) True
b) False
______ a
20) A composite is a material that combines the useful properties of two or more
substances.
a) True
b) False
______ b (nucleic acids)
a) True
21) DNA and RNA are examples of cholesterol.
b) False
______ a
22) A pure form of carbon that forms a very hard crystal is ______.
a) diamond b) graphite
c) fullerene
______ a
23) All hydrocarbons
a) burn easily
b) have carboxyl groups
c) have fruity smells
______ c
24) In a substituted hydrocarbon, an atom of another element replaces a(n) ______.
a) carbon atom
b) oxygen atom
c) hydrogen atom
______ c
25) Proteins are polymers formed from monomers called ______.
a) esters
b) carbohydrates
c) amino acids
______ b
26) Synthetic polymers that can be molded or shaped are ______.
a) cellulose b) plastics
c) isomers
______ c
27) Carbohydrates give your body ______.
a) the building blocks to repair body parts
b) helper molecules for chemical reactions in your body
c) energy
Ch 8 Practice Test – Answer Key
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Mrs. Lee – 8th Grade Physical Science
Page 3
Chapter 8 Practice Test – Answer Key
______ a
28) The building blocks of proteins are ______.
a) amino acids
b) nucleic acids
c) fatty acids
______ c
29) Which food is a source of fat?
a) potatoes
b) rice
c) butter
______ b (nanotube) 30) A form of pure carbon in which carbon atoms are arranged in the shape of
a long, hollow tube is a fullerene.
a) True
b) False
______ a
31) Compounds with the same chemical formula but different structural formulas are
called isomers.
a) True
b) False
______ b (composite)32) Two or more substances combined in a new material with different
properties is a DNA.
a) True
b) False
______ b (glucose) 33) Starch is a complex carbohydrate made up of molecules of fatty acids.
a) True
b) False
______ b
34) Carbon atoms cannot form chemical bonds with other carbon atoms.
a) True
b) False
______ a
35) Hydrocarbons are organic compounds that contain only the elements hydrogen
and carbon.
a) True
b) False
______ a
36) Polymers are very large molecules made of monomers.
a) True
b) False
______ b
37) Carbohydrates release much more energy in your body than do lipids.
a) True
b) False
______ a
38) The order of nucleotides in a DNA molecule determines the differences among
living things.
a) True
b) False
Ch 8 Practice Test – Answer Key
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Mrs. Lee – 8th Grade Physical Science
Page 4
Chapter 8 Practice Test – Answer Key
Use the diagrams below to answer the following 3 questions:
______ b
39) Interpreting Diagrams: Which is a branched hydrocarbon chain?
a) compound A
b) compound B
c) neither compound is a branched chain
______ b
40) Applying Concepts: What kind of formula is used above to show the
compounds?
a) chemical formula b) structural formula c) chemical equation
______ a
41) Applying Concepts: Which formula correctly describes both compounds above?
a) C4H10
b) C3H7
c) CH4
Use the diagrams below to answer the following 2 questions:
______ a
42) Classifying: What kind of substituted hydrocarbon is compound A?
a) alcohol
b) organic acid
c) halogen-containing compound
______ c
43) Applying Concepts: Which is the correct formula for compound B?
a) C4H
b) CH3Cl
c) CCl4
Ch 8 Practice Test – Answer Key
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