Nam e:
Period:
STAAR Review – Week Three
6.6 (B) calculate density to identify an unknown substance (S)
8.5 (D) recognize that chemical formulas are used to identify substances and determine the number of atoms of each element in
chemical formulas containing subscripts (R)
8.5 (E) investigate how evidence of chemical reactions indicate that new substances with different properties are formed (R)
8.5 (F) recognize whether a chemical equation containing coefficients is balanced or not and how that relates to the law of
conservation of mass (S)
The chart below shows the densities of a variety of substances. Use the chart and your knowledge of science to answer any
questions that follow.
1.
3
A sample of a substance has a mass of 5902.5 grams (g) and a volume of 750 cubic centimeters (cm ). W hat is this
substance?
a.
b.
c.
d.
2.
If the left side of a chemical equation has 3 carbon atoms, 6 oxygen atoms, and 4 hydrogen atoms, then the right side of the
chemical equation will have –
a.
b.
c.
d.
3.
Iron
Mercury
Led
Uranium
the same number of atoms of each element in order to follow the law of conservation of mass.
double the number of atoms of each element in order to follow the law of conservation of mass.
more atoms of each element in order to follow the law of conservation of mass.
fewer atoms of each element in order to follow the law of conservation of mass.
W hich of the following chemical equations follows the law of conservation of mass?
a.
12HClO 4 + P 4 O 10
b.
P 4 O 10 + 6H 2 O
4H 3 PO 4 + 6Cl2 O 7
c.
Ba3 N 2
d.
2Al(OH) 3 + 2H 2 SO 4
2H 3 PO 4
2Ba + N 2
None of them follow the law of conservation
of mass
Al2 (SO 4 ) 3 + 6H 2 O
Pre-AP STAAR Review
4.
W hich of the following chemical equations follows the law of conservation of mass?
a.
b.
c.
d.
5.
C 5 H 12 + 7O 2
5CO 2 + 6H 2 O
GaF3 + 3C5
3C5 F + Ga
2VCl2 + H 2
2HCl + V
2K + Ca(NO 3 )2
K(NO 3 ) + Ca
Look at the following equation.
Au 2 O 3
In order
a.
b.
c.
d.
6.
to follow the law of conservation of mass, this equation must have which set of coefficients, in order from left to right?
1, 1, 3
2, 4, 3
2, 1, 3
1, 3, 1
mass can neither be created nor destroyed.
the mass of the products is always greater than the mass of the reactants.
the mass of the reactants is always greater than the mass of the products.
mass is determined by a chemical reaction.
Look at the following chemical equation.
SnO 2 + H 2
a.
b.
c.
d.
8.
9.
O2
Chemical equations must be balanced because –
a.
b.
c.
d.
7.
Au +
Sn + H 2 O
It is balanced because the number of reactants is equal to the number of products.
It is balanced because the mass of the reactants is equal to the mass of the products.
It is unbalanced because the mass of the reactants is less than the mass of the products.
It is unbalanced because the mass of the reactants is greater than the mass of the products.
W hich equation demonstrates the law of conservation of mass?
MgS 2
a.
Mg + S
b.
c.
d.
b. 2H 2 + O 2
2H 2 O
C + O2
C2 O
H 2 SO 4 + Zn
4ZnSO + H 2
None of them follow the law of conservation
of mass
The diagram below shows the results of combining potassium iodide and lead (II) nitrate.
W hat occurred in the diagram?
a.
b.
c.
d.
A chemical change, because the volume of the final solution was larger than the initial solutions
A chemical change, because a yellow substance formed when the two liquids combined
A physical change, because the temperature changed with no outside source applied
A physical change, because a solid formed when the two liquids combined
Pre-AP STAAR Review
10. Destiny is looking around her house, classifying changes she notices as physical changes or chemical changes. W hich of the
following is a chemical change?
a.
b.
c.
d.
Destiny’s father burns an English muffin.
Destiny’s mother chops celery and onion into small pieces.
Destiny’s sister melts butter in the microwave.
Destiny mixes chocolate syrup into a glass of milk.
The diagram below shows a five-part experiment that Mrs. Hammond showed her students. Use the diagram to answer any
questions that follow.
11. W hen is a chemical reaction NOT occurring?
a.
b.
c.
d.
Between Part 1 and Part 2
During Part 3
Between Part 4 and Part 5
During Part 5
12. W hich of the following does NOT indicate that a chemical change occurred to the penny?
a.
b.
c.
d.
A change in the luster of the penny
A change in the size of the penny
A change in the outer texture of the penny
A change in the color of the penny
13. In a lab demonstration, Mr. Sharpe placed a piece of zinc (Zn) into a glass beaker containing hydrochloric acid (HCl). W hen
the two substances were mixed, the zinc turned black and hydrogen gas was released. Mr. Sharpe then asked his students
when kind of change took place and why. W hat would have been the correct answer?
a.
b.
c.
d.
Chemical change, because the zinc melted
Physical change, because the hydrochloric acid evaporated
Physical change, because the zinc combined with the chlorine in the acid
Chemical change, because at least one new substance was created
14. A food scientist placed a raw egg in a pan and cooked it. The white and yolk became a thick, solid mass. W hat evidence
indicates that a chemical reaction occurred when the egg was cooked?
a.
b.
c.
d.
W ater vapor was released as the egg was heated.
Som e of the raw egg was boiled and released as a gas.
The cooked egg cannot return to its raw state.
The egg changed from a liquid state to a solid state.
15. An iron chain on a fence was exposed to air and rain. W hat evidence indicates that a chemical reaction between the water, air
and iron produced a new substance?
a.
b.
c.
d.
The mass of the chain decreased as pieces broke off.
The surface of the chain becam e wet.
The surface of the chain began to turn red.
The temperature of the chain dropped as water evaporated.
Pre-AP STAAR Review
16. The diagram below shows an experiment that Mr. McElroy performed for his students.
W hich of the following does NOT indicate that a chemical reaction occurred?
a.
b.
c.
d.
The final solution was black.
The potassium chlorate changed to a liquid.
Smoke was produced.
A flame formed inside the test tube.
17. Mr. W urtz performed a demonstration for his science students in a well-ventilated room. He mixed together two samples of
different white powdery substances in an open beaker. The dry mixture soon becam e wet, and the students could smell
amm onia. The temperature of the beaker dropped dramatically, so much so that the liquid that formed in the beaker began to
freeze.
Mr. W urtz told the class that a chemical reaction had occurred inside the beaker. W hich of the following is NOT evidence that a
chemical reaction occurred?
a.
b.
c.
d.
The powdery substances dissolved in the water.
A gas with a strong smell was released from the mixture.
The temperature of the mixture dropped dramatically.
A liquid formed at the bottom of the beaker.
Pre-AP STAAR Review
A balanced chemical equation is shown below. Use this equation to answer any questions that follow. Record your answer and fill
in the bubbles on your answer document. Be sure to use the correct place value.
2H 2 O + O 2
2H 2 O 2
18. How many atoms of oxygen (O) are represented on the left side of the arrow in the chemical reaction?
19. How many different elements are involved in this chemical reaction?
20. How many different compounds are involved in the reaction shown below?
2NaCl + H 2 SO 4
2HCl + Na2 SO 4
21. Boric acid has the following chemical formula:
H 3 BO 3
One molecule of boric acid contains a.
b.
c.
d.
1 hydrogen atom, 3 boron atoms, and 3 oxygen atoms
3 hydrogen atoms, 3 boron atoms, and 1 oxygen atom
3 hydrogen atoms, 1 boron atom, and 3 oxygen atoms.
1 hydrogen atom, 1 boron atom, and 3 oxygen atoms.
Pre-AP STAAR Review
22. Glucose, the kind of sugar that plants produce by photosynthesis, has the following chemical formula:
C6H12O6
One molecule of glucose contains a.
b.
c.
d.
6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms.
1 carbon atom, 1 hydrogen atom, and 1 oxygen atom.
1 carbon atom, 2 hydrogen atoms, and 1 oxygen atom.
6 carbon atoms, 1 hydrogen atom, and 6 oxygen atoms.
23. Substances have chemical formulas. A chemical formula can NOT be used to –
a.
b.
c.
d.
identify a substance.
identify specific isotopes in a substance.
determine the number of individual atoms in a substance.
determine the type of elements in a substance.
The table below shows the densities of various substances. Use the table to answer any questions that follow.
3
24. If a sample of a pure substance has a volume of 5 cm and a mass of 5 g, then the substance could be –
a.
b.
c.
d.
gold.
iron.
water.
cork.
3
25. If a sample of a pure substance has a volume of 12.3 cm and a mass of 97.17 g, then the substance could be –
a.
b.
c.
d.
water.
iron.
gold.
cork.
3
26. If a sample of a pure substance has a volume of 10 cm and a mass of 193 g, then the substance could be –
a.
b.
c.
d.
iron.
water.
gold.
cork.
Pre-AP STAAR Review
The diagram below shows a table of liquids with their assigned densities and four different unknown liquids in graduated cylinders.
Use the diagram to answer any questions that follow.
27. W hat liquid is Unknown 1?
a.
b.
c.
d.
Methanol
Ethanol
Glycerin
Syrup
28. W hat liquid is Unknown 3?
a.
b.
c.
d.
Glycerin
Syrup
Methanol
Ethanol
29. W hat liquid is Unknown 4?
a.
b.
c.
d.
Methanol
Syrup
Ethanol
Glycerin
Pre-AP STAAR Review
30. The diagram below shows an unknown substance, W , that is weighed on a scale and then placed into a graduated cylinder with
water. Use this diagram and the table of densities to answer the question below.
W hat is unknown substance W ?
a.
b.
c.
d.
Magnesium
Aluminum
Silver
Cobalt
31. The diagram below shows an unknown substance, X, that is weighed on a scale and then placed into a graduated cylinder with
water. Use this diagram and the table of densities to answer the question below.
a.
b.
c.
d.
Magnesium
Aluminum
Cobalt
Silver
Pre-AP STAAR Review
3
32. A sample of a substance has a mass of 10,146 g and a volume of 890 cm . W hat is this substance?
a.
b.
c.
d.
Air (dry)
Lead
Magnesium
Gasoline
3
33. A sample of a substance has a mass of 3240 g and a volume of 360 cm . W hat is this substance?
a.
b.
c.
d.
Gold
Copper
Iron
Lead
3
34. A sample of a substance has a mass of 432 g and a volume of 32 cm . W hat is this substance?
a.
b.
c.
d.
Mercury
Copper
Milk
Bone
3
35. A sample of a substance has a mass of 67.2 g and a volume of 96 cm . W hat is this substance?
a.
b.
c.
d.
Gasoline
Osmium
Bone
Magnesium
3
36. A sample of a substance has a mass of 6000 g and a volume of 3000 cm . W hat is this substance?
a.
b.
c.
d.
Bone
Iron
Gold
Magnesium
3
37. A sample of a substance has a mass of 1370.3 g and a volume of 71 cm . W hat is this substance?
a.
b.
c.
d.
Lead
Platinum
Iron
Gold
Pre-AP STAAR Review
3
38. A sample of a substance has a mass of 90 g and a volume of 4cm . W hat is this substance?
a.
b.
c.
d.
Osmium
Milk
Mercury
Gasoline
The diagram below shows a table with the densities of four metals and four unknown metal cubes: Q, R, S, and T. Use the table
and the dimensions of the cubes to answer any questions that follow.
39. If cube Q has a mass of 40.74 g, then what is unknown metal Q?
a.
b.
c.
d.
Gold
Zinc
Silver
Aluminum
40. If cube S has a mass of 35.40 g, then what is unknown metal S?
a. Zinc
b. Silver
c. Aluminum
d. Gold
Pre-AP STAAR Review