Content Benchmark P.8.A.5
Students know mass is conserved in physical and chemical changes. E/S
Sample Test Questions
1st Item Specification: Identify that the total mass remains the same in a chemical
change (i.e., the number and type of atoms in the reactants equals the number and
type of atoms in the products).
Depth of Knowledge Level 1
1. Examine the following table and use it to answer the following question.
2H2
+
O2
2H2O
+
2 * 2.02g + 32.00g
=
?g
(From http://www.visionlearning.com/library/module_viewer.php?mid=56)
What is the total mass of water formed?
A. 2.02 g
B. 32.0 g
C. 36.0 g
D. 18.0 g
2. In chemical and physical changes,
A. mass is gained, but energy remains the same after the changes occur.
B. both mass and energy remain the same after the changes occur.
C. both mass and energy are lost after the changes occur.
D. mass is lost, but energy remains the same after the changes occur.
3. Which of the following statements is true of a chemical reaction?
A. Mass is converted into energy.
B. Energy is converted into mass.
C. Mass and energy are conserved.
D. Mass and energy are not involved.
4. Examine the following reaction:
Ca + Cl2  CaCl2
According to the Law of Conservation of Mass,
A. there should be equal numbers of atoms on both sides of the equation.
B. the mass of the products should be less due to bonding changes.
C. the mass of the products increases because energy changes to mass.
D. the numbers of atoms should be decreased due to nuclear changes.
5. According to the Law of Conservation of Mass the number of iron atoms needed to
complete the following reaction is
___Fe + 3O2  2Fe2O3
A.
B.
C.
D.
1
2
3
4
Depth of Knowledge Level 2
6. A student dissolves 5 grams of salt in 20 grams of water. The mass of the resulting
solution is
A. less than 25 grams because some of the salt disappears.
B. less than 25 grams because water weighs less than salt.
C. equal to 25 grams because the mass includes all of the salt and all of the
water.
D. more than 25 grams because some of the salt weighs more when it dissolves in
water.
7. A student masses a quantity of vinegar and baking soda and places them into a
massed Ziploc® bag. The bag begins to expand as the vinegar and baking soda react
vigorously with each other. When the reaction is complete, the student re-masses the
bag. Which of the following statements is true?
A. The mass of the bag and its contents is the same as the original mass of the
substances.
B. The mass of the bag and its contents is less than the original mass of the
substances.
C. The mass of the bag and its contents is more than the original mass of the
substances.
D. The mass cannot be determined because energy changes were not considered.
8. A student measures the mass a piece of metal and places it in a dish at his desk. After
a week, he observes that the metal has changed appearance. He re-masses the metal
and notes that its mass has increased. What is the correct explanation for his
observation?
A. Time causes the mass of objects to change.
B. Mass does not change so the metal cannot be the same metal.
C. A reaction with the air occurred causing a new substance to form.
D. The balance contained an error and should be recalibrated.
9. Two chemicals, A and B, react to form compounds C and D. If 12 grams of A react
completely with 5 grams of B, and 7 grams of D are formed, then how many grams of
C are formed?
A+BC+D
A.
B.
C.
D.
5 grams
7 grams
10 grams
17 grams
10. Given the balanced equation
6CO2(s) + 6H2O (aq)  C6H12O6 (aq) + 6O2(g)
How many atoms of oxygen are reacting?
A. 6
B. 7
C. 12
D. 18
2nd Item Specification: Know matter is conserved in a physical change.
Depth of Knowledge Level 1
11. When a gas condenses to the liquid state, its mass
A. changes because the phase has changed.
B. remains the same even though the phase has changed.
C. is lighter because gases weigh less than liquids.
D. is heavier because liquids weigh more than gases.
12. In the figures below, molten gold is solidified. Use the figures to answer the
following question.
(From http://www.answer.com)
(From www.ebsinstitute.com)
Which of the following describes what is happening as the molten gold is
solidified?
A. Atoms are lost during the solidification process.
B. Atoms are lost during the melting phase.
C. Atoms are gained in phases changes.
D. Atoms remain the same during phase changes.
13. The figure below shows a piece of metal being pounded by a hammer. Use the figure
to answer the following question.
(From http://www.burningideas.com)
When a piece of metal is being pounded by a hammer, the impact causes
A. atoms to be smashed into smaller pieces.
B. the metal to change its chemical formula.
C. no change in the metal’s chemical properties.
D. energy changes in the nucleus of the metal’s atoms.
14. A student burns a candle in the laboratory and makes several observations. Which of
her conclusions is correct?
A. The mass of the candle does not include the gases that escaped.
B. The candle is composed of the wax left over from the burning candle.
C. The candle’s behavior is affected by the type of wick it has.
D. The mass of the remainder of the candle is heavier because it is denser.
15. A student masses three equal amounts of salt. She then dissolves them in different
amounts of water. She then evaporates the water and re-masses each sample of salt.
All the amounts will be
A. different because different amounts of water were used.
B. different because of density differences in the substances.
C. the same because different amounts of water were used.
D. the same because the substances did not physically change.
Depth of Knowledge Level 2
16. A student is studying the phase change of ice (solid water) to liquid water to steam
(gaseous water). The student correctly predicts that
A. the total mass of ice changing to liquid phase is the same because mass is
conserved.
B. the total mass of ice will be less in the water phase because water takes up less
volume than ice.
C. the total mass of water converting to steam will be less because gases do not
contribute to the mass of a substance.
D. the mass of the ice will be more than the mass of steam because solids are
heavier.
17. The melting of wax is a physical change, yet the burning of wax is a chemical change.
What is the primary difference between the chemical change and physical change of
wax in a burning candle?
A. The burning of wax forms new compounds, while the melting of wax does
not.
B. A higher temperature is needed to burn wax than to melt wax.
C. Melted wax can be separated into other substances, while solid wax cannot.
D. Melted wax is a different phase of matter than solid wax.
18. A student is trying to distinguish between physical and chemical changes. He states
that in physical changes, mass is not conserved. Which of the following would help
correct his thinking?
A. Tear 5.0 grams of paper and examine the ripped edges.
B. Take 5.0 grams of ice melt it and remass it.
C. Take 5.0 grams of charcoal and burn it.
D. Take 5.0 grams of sugar and dissolve it in water.
19. A student takes a small piece of dry ice and notices that it is not visible (sublimes) in
a few minutes. She concludes that dry ice does not contain atoms. Which of the
following might correct her thinking?
A. Take more dry ice, mass it and then observe it sublime.
B. Take the dry ice, place it in a bag and mass it before and after it sublimes.
C. Take the dry ice, mass it, and then mix it with water to see if it reacts.
D. Take the dry ice, mass it, and then time how long it takes to sublime.
Constructed Response P.8.A.5
1. A student takes a small piece of dry ice, places it in a Ziploc bag, and masses it. After
a few minutes she observes that it is not visible. She re-masses the bag and finds that
the quantity has not changed. How would you explain her observations?
Content Benchmark P.8.A.5
Students know mass is conserved in physical and chemical changes. E/S
Answers to Sample Test Questions
1. C, DOK Level 1
2. B, DOK Level 1
3. C, DOK Level 1
4. A, DOK Level 1
5. D, DOK Level 1
6. C, DOK Level 2
7. A, DOK Level 2
8. C, DOK Level 2
9. C, DOK Level 2
10. D, DOK Level 2
11. B, DOK Level 1
12. D, DOK Level 1
13. C, DOK Level 1
14. A, DOK Level 1
15. D, DOK Level 1
16. A, DOK Level 2
17. A, DOK Level 2
18. B, DOK Level 2
19. B, DOK Level 2
Constructed Response 3-point Answers and Score Rubrics:
3 points
Response addresses all parts of the question clearly and correctly.
Student response indicates that dry ice is a solid and sublimes (or
answer similar), only a physical change has occurred, gases have
mass and occupy volume, and mass is conserved in physical
changes.
2 points
Response addresses all parts of the question and includes only
minor errors.
1 point
Response does not address all parts of the question.
0 point
Response is totally incorrect or no response provided.