What is Matter? Classwork
Name: _________________________
7th Grade PSI Science
1
1. If you have one atom of Oxygen and you break it in half,
would you still have
Oxygen? Explain.
2. Draw a model of an atom labeling all of its parts. On your model, identify which
parts have a positive or negative charge or have no charge.
3. Explain what would happen if an electron and a proton were brought near each
other and then released. Why would this happen?
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7th grade PSI
Matter and Its Properties
What is Matter? Homework
Name: _________________________
7th Grade PSI Science
4.
5.
6.
7.
8.
How do we define “matter?”
Can you think of anything that is not matter?
What does it mean for a substance to be a “pure substance?”
What subatomic particle has a neutral charge?
Where are electrons found in the atom?
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Matter and Its Properties
How Do We Measure Matter? Classwork
Name: _________________________
7th Grade PSI Science
9. For each item below, identify the appropriate unit of measurement. The choices for
the unit of measurement are: volume (V), weight (W), mass (M) or both mass and
weight (MW).
a. _______ Amount of water in a pool
b. _______ Force of gravity on an apple
c. _______ Kilograms
d. _______ Amount of matter in a stone
e. _______ Newton
f. _______ Measured with a graduated cylinder
g. _______ Cubic meters
h. _______ Length x Width x Height
i.
_______ Amount of juice in an orange
j.
_______ Pounds
k. _______ Depends on location in a gravitational field
l.
_______ Grams
m. _______ Measured with a scale
n. _______ Liters
10. Rank your weight on the surface of each of these locations from greatest to least.
Justify your ranking to the right of the table.
Location Ranking
Moon
Jupiter
Mercury
Earth
11. Describe how you would find the volume of the empty vase to the right. Note that
the vase is too large to fit in a standard graduated cylinder.
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7th grade PSI
Matter and Its Properties
How Do We Measure Matter? Homework
Name: _________________________
7th Grade PSI Science
For each question below, show your work and/or justify your answer.
12. How many grams would be in 10 kilograms?
13. A block has a mass of 10 kg on Earth and a weight of 60 lbs. What would its mass
and weight be on the moon?
14. A box has a length of 10 cm, a width of 8.5 cm and a height of 5.5 cm. What is its
volume?
15. An irregular object is placed in 50 mL of water and the water level rises to 72 mL.
What is the volume of the object?
16. Explain why the following statement is incorrect and then correct it: The apple
weighs 1 kilogram.
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Matter and Its Properties
Elements of the Periodic Table Classwork
Name: _________________________
7th Grade PSI Science
17. What did Mendeleev use to organize his first Periodic Table of Elements?
18. What is the symbol for Magnesium?
19. Which element is represented by the symbol C?
20. What period is Hydrogen (H) located in?
21. What group is Sulfur (S) located in?
22. Pick another atom with similar characteristics for each of these elements:
a. Fluorine (F)
b. Oxygen (O)
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7th grade PSI
Matter and Its Properties
Elements of the Periodic Table Homework
Name: _________________________
7th Grade PSI Science
23. How is the modern Periodic Table of Elements arranged?
24. Use your Periodic Table to answer the following questions about Helium (He):
a. Atomic number?
b. Element symbol?
c. Atomic mass?
d. Number of protons?
e. Period?
f. Group?
g. Number of electrons in outer shell?
25. Suppose an element had an atomic number of 52. How many protons would that
element have?
26. Using your Periodic Table, what element has an atomic number of 65?
27. Using your Periodic Table, which element has more protons: Nickel or Iodine? How
do you know?
28. Which element is represented by the symbol W?
29. What period is Silver (Ag) located in?
30. What group is Xenon (Xe) located in?
31. Pick another atom with similar characteristics for each of these elements:
a. Potassium (K)
b. Krypton (Kr)
c. Strontium (Sr)
d. Gold (Au)
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7th grade PSI
Matter and Its Properties
Physical Properties Classwork
Name: _________________________
7th Grade PSI Science
32. An unidentified clear liquid substance is found in the chemistry lab. One of your lab
partners claims it is simply water while the other thinks it is isopropyl alcohol.
a. What physical properties would NOT be helpful in identifying the substance
and why?
b. Explain which physical properties could be used to identify the substance and
how you and your lab partners would test these physical properties.
33. Describe the physical properties of a tent that are important if you are going
camping for the weekend. For each physical property described, explain why it is
important.
34. You are given a mixture composed of finely ground salt and pepper and coarse
sand. Explain how the physical properties of each item can help you separate them.
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7th grade PSI
Matter and Its Properties
Physical Properties Homework
Name: _________________________
7th Grade PSI Science
35. Explain what physical properties of metal would be a good choice of material for
each of these products and why:
a. Cooking pot
b. Power lines
c. Refrigerator door
36. Describe how the difference between metals and nonmetals can be detected.
37. For each item below, choose the most appropriate term. In some cases, you may
have more than one term listed: compound (C), molecule (M), element (E) or atom
(A).
a. ______ Basic unit of an element
b. ______ Water
c. ______ Pure substance
d. ______ Smallest part of a compound
e. ______ O3
f. ______ salt
g. ______ Carbon
h. ______ Two or more elements chemically bonded together
i.
______ The subscript in H2O
j.
______ C6H12O6
k. ______ One or more atoms that are chemically bonded together
38. Write the name of the family that is described in a-g:
a. Does not react with other elements
b. End in –ine
c. React by losing 2 electrons
d. Poor conductor of electricity
e. 1 electron in the outer shell
f. Contains many unstable elements that do not occur naturally on earth
g. Can be mixed with other metals to make alloys
39. CaCO3, CO2, CuSO4, NaHCO3
Rank the compounds listed above from greatest to least based on:
a. The number of different elements.
b. The total number of atoms.
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Matter and Its Properties
40. What is the ratio of Sodium (Na) to Chlorine (Cl) atoms in the chemical formula
NaCl? _________
41. The ratio of Carbon to Oxygen atoms in Carbon Dioxide is 1:2. How would you
write its formula? _________________
42. The molecule commonly known as Acetylene (C2H2) is made up of what types of
atoms (and how many of each)?
43. The molecule commonly known as Nutrasweet (C14H18N2O5) is made up of what
types of atoms (and how many of each)?
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Matter and Its Properties
Density Classwork
Name: _________________________
7th Grade PSI Science
44. Complete the table below. Show your mathematical work on another sheet of
paper. A periodic table displaying the density of elements is provided to help you.
Mass (g)
Volume(cm3)
345.5
356.1
155.3
57.5
Density (g/cm3)
94.2
Element
4.54
10.13
2.7
59.6
4.88
3.14
53.6
23
7.13
Answer the following questions.
45. Can a sample of an element be identified by its mass alone? Why or why not?
46. Suppose you had samples of equal mass for every element on the periodic table.
a. Which elemental sample would contain atoms that are the most closely
packed together? Justify your answer.
b. The least closely packed? Justify your answer.
47. You have one 3g sample of Nickel and one 3g sample of Manganese.
a. Which sample takes up more physical space? Justify your answer.
b. Would either sample float in water? Why or why not?
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Matter and Its Properties
48. A graduated cylinder is filled with 50mL of water. A sample of gold with a mass of
39.5 grams is dropped into the water. What will be the new water level on the
graduated cylinder? Justify your answer.
Periodic Table of the Elements, Density (g/cm3) (25 oC)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
1
H
0.090
He
0.178
2
Li
0.53
Be
1.85
B
2.34
C
2.26
N
O
F
Ne
1.251 1.429 1.696 0.900
3
Na
0.97
Mg
1.74
Al
2.70
Si
2.33
P
1.82
S
2.07
Cl
Ar
3.214 1.784
4
K
0.86
Ca Sc
Ti
1.55 2.99 4.54
V
6.11
Cr
7.19
Zn
7.13
Ga
5.91
Ge
5.32
As
5.78
Se
4.79
Br
3.12
Kr
3.75
5
Rb
1.53
Sr
Y
Zr
2.54 4.47 6.51
Nb
8.57
Mo
Tc
Ru
Rh
Pd
Ag
Cd
10.22 11.49 12.37 12.41 12.02 10.49 8.65
In
7.31
Sn
7.31
Sb
6.69
Te
6.24
I
4.93
Xe
5.9
6
Cs
1.87
Ba Lu
Hf
Ta
W
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
3.59 9.84 13.31 16.65 19.25 21.03 22.61 22.65 21.45 19.32 13.55 11.85 11.35 9.75
Po
9.20
At
Rn
9.73
7
Fr
Ra
Lr
5.50
Lv
Lanthanides
Actinides
Rf
Mn
7.44
Fe
Co
7.874 8.89
Ni
8.91
Cu
8.96
Db
Sg
Bh
Hs
Mt
Ds
Rg
Cn
La
6.15
Ce
6.77
Pr
6.77
Nd
7.01
Pm
7.22
Sm
7.52
Eu
5.24
Gd
7.9
Tb
8.23
Dy
8.55
Ho
8.8
Er
9.07
Tm
9.32
Yb
6.97
Cm
13.5
Bk
Cf
Es
Fm
Md
No
Ac
Th
Pa
10.07 11.72 15.4
U
Np
18.95 20.2
Pu
Am
19.84 13.7
Fl
http://chemistry.bd.psu.edu/jircitano/density.html
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7th grade PSI
Matter and Its Properties
Density Homework
Name: _________________________
7th Grade PSI Science
For each question below, show your work and/or justify your answer.
49. What is the density of a piece of wood that has a mass of 25.0 grams and a volume
of 29.4 cm3?
50. I threw a plastic ball in the pool for my dog to fetch. The mass of the ball was 125
grams. What must the volume be to have a density of 0.500 g/mL? (I want it to
float of course!)
51. What is the mass of a 12cm3 sample of pure silicon with a density of 9 g/cm3?
52. A piece of wood that measures 3.0 cm by 6.0 cm by 4.0 cm has a mass of 80.0
grams. What is the density of the wood? Would the piece of wood float in water?
(Hint: recall how to determine the volume of a rectangular shaped object)
53. A strand of gold-colored metal beads was measured to have a mass of 425 grams.
The beads are placed in a graduated cylinder where the original water level was
10mL. After the beads are placed in, the new water level in the graduated cylinder
is 58mL. Given the following densities, identify the metal:
Gold
19.3 g/mL
Copper
8.86 g/mL
Bronze
9.87 g/mL
54. An ice cube measuring 5.80 cm by 5.80 cm by 5.80 cm has a density of 0.917
g/mL. What is the mass?
55. The density of aluminum is 2.70 g/mL. If the mass of a piece of aluminum is 244
grams, what is the volume of the aluminum in cm3?
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7th grade PSI
Matter and Its Properties
States of Matter Classwork
Name:__________________________
7th Grade PSI Science
For each image below, identify an example of each common state of matter. Be sure to
include scientific evidence that justifies your identified examples. Also determine
whether the solid identified is crystalline or amorphous and justify your answer.
56. Root Beer Float
Solid:
Liquid:
Gas:
57. Hot Air Balloons over a lake
Solid:
Liquid:
Gas:
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Matter and Its Properties
58. Ice lake
Solid:
Liquid:
Gas:
59. Geyser
Solid:
Liquid:
Gas:
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7th grade PSI
Matter and Its Properties
States of Matter Homework
Name: _________________________
7th Grade PSI Science
Use the word/phrase bank below to complete the Venn Diagram.
Liquid
Solid
Gas
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7th grade PSI
Matter and Its Properties
Word Bank
Definite volume
Definite shape
Atoms
Particles have highest
energy
Amorphous
Particles are very close
together
Particles slide past each
other
Cannot be compressed
Molecules
H2O at 27°C
Particles vibrate in place
No fixed Shape
Particles are not very
attracted to each other
Crystalline
Fluid
Matter
Has mass
No definite volume
Next, come up with two examples of each state of matter and write them in the correct
place on the Venn Diagram.
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7th grade PSI
Matter and Its Properties
Changes of State Classwork
Name: _________________________
7th Grade PSI Science
The diagram below shows the water cycle- the movement of water throughout the
Earth. Study the diagram and then use it to complete the following questions.
60. Label the arrows that represent evaporation with the letter ‘E’. Describe what is
happening in these locations in terms of the thermal energy and temperature of the
water.
61. Label the arrows that represent condensation with the letter ‘C’. Describe what is
happening in these locations in terms of the thermal energy and temperature of the
water.
62. Label any area on the figure where freezing might occur with an ‘F’. Describe what
is happening in these locations in terms of the thermal energy and temperature of
the water.
63. Are there any areas on the figure where boiling may occur? If so, label these areas
with a ‘B’ and explain why you think it could occur there.
64. At what locations will H20 molecules
a. have the highest energy? Explain.
b. have the lowest energy? Explain.
65. According to the diagram, water is never added or removed from Earth’s system.
Explain how this is possible.
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7th grade PSI
Matter and Its Properties
Changes of State Homework
Name: _________________________
7th Grade PSI Science
66. Why is a substance’s melting point and freezing point the same? Explain your
answer in terms of thermal energy.
67. What differences are there between the two types of vaporization?
68. How can you tell that water is boiling? How can you tell that water is evaporating?
69. For a-d, write E if the sentence is referring to Evaporation and C if it is referring to
Condensation:
a. A substance changes from a liquid to a gas.
b. More molecules are breaking free from a liquid than joining it.
c. More molecules are joining together with a liquid rather than leaving it.
d. Molecules of water vapor are colliding and sticking together in the air.
For #70-75, identify the state of matter of the substances below at room temperature.
Plot and label 0 °C, the melting point (MP), the boiling point (BP), and room
temperature (RT, 20 °C) on a number line.
70. Mercury
71. Nickel
72. Silicon
73. Bromine
74. Chlorine
75. Zinc
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MP
-39 °C
MP 1455 °C
MP 1414 °C
MP
-7 °C
MP -102°C
MP
420°C
BP
BP
BP
BP
BP
BP
7th grade PSI
357 °C
2913 °C
3265 °C
59°C
-34°C
907°C
Matter and Its Properties
Chemical Properties Classwork
Name: _________________________
7th Grade PSI Science
76. How do physical properties differ from chemical properties?
77. Where can the most reactive elements be found in the Periodic Table? Where can
the least reactive elements be found?
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7th grade PSI
Matter and Its Properties
Chemical Properties Homework
Name: _________________________
7th Grade PSI Science
For #78-86, label each of these properties as chemical (C) or physical (P). Explain your
choice.
78. Density
79. Tendency to corrode
80. Odor (scent)
81. Boiling/Melting Point
82. Reacts with acid
83. Solubility (dissolves)
84. Flammability
85. Reacts with Oxygen
86. Texture
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Answer Key
1) If you were to split one atom of Oxygen in half, you would no longer have Oxygen.
All atoms of Oxygen must have 8 Protons and, in order to be stable, must have 8
Electrons as well.
2) Model description: electrons with a negative charge surrounding the nucleus
(neutral) which contains protons (positive charge) and neutrons (no charge).
3) They would be attracted to each other because opposite charges attract and an
electron is negatively charged while a proton has a positive charge.
4) Matter is anything that has mass and takes up space. Every object and substance
in the universe is considered matter.
5) Something that is not matter would be anything that is not tangible. This includes
feelings, thoughts and emotions. Electricity and magnetic fields are actually matter
(they are the 4th state of matter that we will not discuss in this unit called “plasma”).
6) A “pure substance” is an object that can’t be broken down any further without being
changed into something new.
7) Neutrons
8) Electron Shell
9)
a. V
b. W
c. M
d. M
e. W
f. V
g. V
h. V
i. V
j. W
k. W
l. M
m. MW
n. V
10) Justification- Weight depends on the size of the planet. The bigger the planet, the
more your weight.
Location Ranking
Moon
4
Jupiter
1
Mercury
3
Earth
2
11) Since the object is hollow, fill it with a liquid. A liquid does not have a definite shape
and will therefore fill up the entire object. Next, pour the water into a graduated
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Matter and Its Properties
cylinder and measure the amount of water in the graduated cylinder. Since the
object is larger than a graduated cylinder, you will have to repeat this process until
all the water in the object has been emptied out. Then you will have to add up all the
measurements from the graduated cylinder to get the total volume of the object.
12) There are 10,000 grams in 10 kg; because there are 1000 grams in 1 kg
13) Mass = 10 kg; Weight = 10 lbs; Mass stays the same since it measures the amount
of “stuff” in an object. The amount of stuff won’t change even if an object changes
locations. The weight is 1/6 less on the moon than on Earth due to the moon’s
smaller size. Weight depends on location, specifically the gravitational field.
14) Volume = 467.5 cm3 (10cm x 8.5cm x 5.5cm)
15) 22 mL (72mL-50mL)
16) The statement is incorrect because the wrong unit of measurement is used with the
unit kilogram. Correct: The apple has a mass of 1 kilogram OR The apple weights 1
Newton.
17) He used common characteristics of the elements to sort them into groups. He then
noticed that there was a pattern in their atomic weights.
18) Mg
19) Carbon
20) Period 1
21) Group 16
22) For a and b, elements with similar characteristics will be those that are located in the
same group:
a. Fluorine – Chlorine, Bromine, Iodine and Astatine
b. Oxygen – Sulfur, Selenium, Tellurium and Polonium
23) The modern Periodic Table of Elements is arranged according to Atomic Number
(the number of protons in one atom)
24)
a. Atomic # = 2
b. Element Symbol = He
c. Atomic Mass = 4
d. Number of Protons = 2
e. Period = 1
f. Group = 18
g. Number of Electrons in Outer Shell = 2 (There are 2 Protons, therefore there are
only 2 Electrons. Every other element in Group 18 has 8 Outer Electrons)
25) 52 Protons
26) Terbium
27) Iodine; Iodine has an atomic number of 53 and Nickel has an atomic number of 28.
This means that Iodine has 53 protons and Nickel has 28.
28) Tungsten
29) Period 5
30) Group 18
31) Same as for #24
a. Potassium – Hydrogen, Lithium, Sodium, Rubidium, Caesium and Francium
b. Krypton – Helium, Neon, Argon, Xenon and Radon
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7th grade PSI
Matter and Its Properties
c. Strontium – Beryllium, Magnesium, Calcium, Barium and Radium
d. Gold – Copper and Silver
32) a. Sample Student Response
Color- both alcohol and water are clear
Hardness/texture- both alcohol and water are fluid liquids at room temperature
State- both alcohol and water are fluid liquids at room temperature and the
substance was described as being liquid
b. Sample Student Response
Odor- alcohol has a strong, distinct odor while water is odorless. Test for this
physical property by smelling each substance safely.
Boiling point- isopropyl alcohol has a lower boiling point than water. Test for this
physical property by boiling both substances and measuring the temperature at
which it boils.
33) Sample Student Response:
Mass- A tent should have a light mass so it is easy to carry and pack up.
Color- The color is important because if you are using it during the day, you would
want the color to be light so it will not absorb a lot of sunlight and get hot inside the
tent.
Texture/material- The texture/material of the tent should be considered to keep out
bugs, rain and sun.
34)
 The differences in the size of the salt and pepper compared to the sand
pieces could be used to separate the sand from the salt and pepper. The
mixture could be sifted through a fine mesh to isolate the sand.
 The fact that salt is soluble in water could be used to further separate the
mixture. Pour the remaining salt and pepper in a cup of water and stir until the
salt dissolves. Then pour the salt/pepper/water mixture through a coffee filter.
This will isolate the pepper. Let the salt water sit out so the water evaporates,
leaving the salt.
35)
a. The high conductivity of metal in a cooking pot will help transfer the energy from
the heat source (such as a stove top) to the food in the pot.
b. Metal power lines will conduct electricity well.
c. Metal’s magnetic physical property is useful for a refrigerator door because it will
allow you to attach magnets.
36) By testing the following physical properties, one can detect the difference between
metals and nonmetlas:
Heat conductivity- metals transfer heat easily while nonmetals do not
Electric conductivity- metals conduct electricity well while nonmetals do not.
Hardness- metals are very hard and will not break, yet are malleable. Nonmetals will
break easily.
Shininess- Metals are shiny, while non-metals are dull.
37)
a. A
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7th grade PSI
Matter and Its Properties
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
C, M
E
M
M
C, M
E
C, M
A
C, M
M
38)
a.
b.
c.
d.
Noble gases
Halogens
Alkaline earth metals
Nonmetals
e. Alkali metals
f. Actinides
g. Lanthanides
39)
a. NaHCO3 > CaCO3 = CuSO4 > CO2
b. NaHCO3 = CuSO4 > CaCO3 > CO2
40)
41)
42)
43)
44)
1:1
CO2
2 Carbon atoms and 2 Hydrogen atoms.
4 Carbon atoms, 18 Hydrogen atoms, 2 Nitrogen atoms and 5 Oxygen atoms
Mass (g)
Volume(cm3)
Density (g/cm3)
Element
345.5
356.1
0.97
Sodium
155.3
57.5
2.7
Aluminum
94.2
20.75
4.54
Titanium
10.13
2.7
3.75
Krypton
424.9
59.6
7.13
Zinc
4.88
3.14
1.55
Calcium
53.6
23
2.33
Silicon
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7th grade PSI
Matter and Its Properties
45) No, you could have two different elements with the same mass but there would
clearly be other physical properties associated with each that would be different
such as the density, color, etc. You need more than one physical property to identify
an element.
46)
a. Iridium- it has the largest density. Density is a measure of how closely packed
particles are to one another.
b. Hydrogen- it has the smallest density. The lower the density, the less closely
particles are packed.
47)
a. Manganese; Calculate the volume of each to determine which takes up more
space. Manganese volume = 0.40 g/cm3, Nickel volume = 0.33 g/cm3.
b. Both samples would sink in water since their densities are greater than the
density of water
48) D= 19.32 g/mL, M= 39.5 g therefore V=2.044 mL. The new water level will be 50mL
+ 2.044 mL = 52.044mL
49) D = 0.85 g/cm3
50) V = 250 mL
51) M = 108 g
52) D = 1.1 g/cm3; the wood would sink because it has a greater density than water.
53) The metal is a sample of Copper (8.86 g/mL)
54) M = 179 g
55) V = 90.4 cm3
56) Sample Student Response
Solid: The glass holding the root beer- It has a definite shape and takes up a definite
amount of space. It would not compress under pressure. It is amorphous because
the particles are not arranged in a regular pattern and does not have a distinct
melting point.
Liquid: The root beer- It takes the shape of the glass but has a definite volume.
Particles flow past each other making the root beer fluid.
Gas: The carbon dioxide gas bubbles of the root beer- It expanded out of the glass
and doesn’t have a definite shape or volume.
57) Sample Student Response
Solid: The outside of the balloon- Even though it is flexible, it is a solid because it
has a definite volume and shape (once deflated or blown up). It is amorphous
because the particles are not arranged in a regular pattern and likely does not have
a distinct melting point because it is made of different materials.
Liquid: Water in the lake below- It takes the shape of the ground holding it, but has a
definite volume. Particles in the water easily flow past each other.
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Matter and Its Properties
Gas: The hot air in the balloon- It expands to fill up the shape of the balloon and
therefore does not have a definite shape or definite volume. If the balloon fabric
were removed, the hot air would escape and expand out everywhere as the particles
in a gas are not very attracted to each other.
58) Sample Student
Solid: The ice surrounding the lake- The ice has a definite volume and fixed shape. It
is a crystalline solid as the particles are arranged in a regular pattern and ice has a
fixed melting point.
Liquid: Water in the in the lake- It takes the shape of the ground holding it, but has a
definite volume. Particles in the water easily flow past each other making it a fluid.
Gas: The atmospheric gas (air)- The air expands and does not have a definite shape
or definite volume.
59) Sample Student Response
Solid: The rocks surrounding the geyser- These rocks take up a fixed amount of
space and have a definite shape and volume. It is hard to say if the rocks are
amorphous or crystalline because we don’t know what minerals compose the rocks.
Liquid: Water shooting out of the geyser- It has a fixed volume but no definite shape.
As it shoots out of the geyser, its shape will be determined by whatever solid it
comes in contact with. For example, as it hits the ground it will form small puddles
due to the shape of the ground. Particles in the water easily flow past each other
making this a fluid.
Gas: The hot steam from the geyser- This steam does not have a definite shape or
volume but instead expands up and out.
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7th grade PSI
Matter and Its Properties
Liquid

Solid


H2O at 27 C




Fluid
No definite
volume
No fixed shape
Particles slide
past each
other







Definite volume
Can not be
compressed






Particles vibrate in
place
Definite shape
Crystalline
Amorphous
Particles are very
close together
Matter
Atoms
Molecules
Has Mass
Particles are not very attracted to
each other
Particles have highest energy
Gas
*Examples of each state of matter on the Venn Diagram will vary.
60) Any arrow that points up from a surface of water to the sky is acceptable; the water
at these locations is being heated by the sun which adds thermal energy to the water
causing the phase change from liquid to gas in the atmosphere
61) Any arrow in the atmosphere/clouds (up or down); at these locations water vapor
has reached higher altitudes where it is cooler thus removing thermal energy
causing the phase change from water vapor to liquid.
62) Any location where there is ice; at these locations, liquid precipitation that
condensed out from the clouds may freeze high up in the mountains where it is cold
and thermal energy is lost.
63) Boiling may occur at the location of the volcano. Here, there may be enough thermal
energy deep below Earth’s surface to turn the liquid in the volcano to a gaseous
state.
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7th grade PSI
Matter and Its Properties
64) a. Any locations where evaporation occurs. Gases have particles that have energy
and thus move fast causing them to spread out if not contained.
b. Any locations where there is ice indicating freezing. As water freezes, thermal
energy is lost and the result is low energy particles move more slowly, eventually
just vibrating in position.
65) Because water simply changes states.
66) Since melting and freezing are opposites of each other, it takes the same amount of
thermal energy to go from solid to liquid as it does to go from liquid to solid. In one
case thermal energy is added and in the other it is removed, however it is the same
amount.
67) Evaporation occurs at the surface of a liquid and boiling occurs below the surface of
a liquid.
68) You can tell that water is boiling when water vapor bubbles rise to the surface of the
water and escape. You can tell that water has evaporated when you see that the
amount of water has lessened (such as in a puddle on the road).
69)
a. E
b. E
c. C
d. C
70) Liquid
71) Solid
72) Solid
73) Liquid
74) Gas
75) Solid
76) Physical properties are easily observable without changing the substance. You can
only observe chemical properties by destroying the substance or changing it into
something new (such as setting it on fire).
77) The most reactive are on the left side of the Periodic Table. The least reactive are
on the right side of the Periodic Table.
78) P; When finding the density, you do not destroy the substance, you only measure it.
79) C; Corroding means to break down. If a substance breaks down, the original
substance is destroyed and it has changed into something new.
80) P; By smelling an object, you do not destroy it.
81) P; When a substance changes state, it may look different but it is still the same
substance. For example, when ice melts, it is still water. When liquid water boils, it
remains water.
82) C; If a substance reacts with acid, the original substance is destroyed.
83) P; When you dissolve a substance in another (for example, stirring sugar into
water), it does not just disappear. It keeps its same physical and chemical
properties. It is not destroyed.
84) C; If a flammable substance is lit on fire, it is destroyed. The ash left over is a new
material.
85) C; The word “reacts” is a clue that the original object will be destroyed and it will
become something new.
86) P; You can observe the texture of a substance without destroying it.
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7th grade PSI
Matter and Its Properties