FINAL EXAM STUDY GUIDE
PHYSICAL SCIENCE 8TH GRADE
The chapters that will be included on your final science exam are as follows: Chapters 20, 21, 22, 23:2,
10, 2:2, 4, 11, 12, 13, 14, and 15:2. This is only material from the 2nd semester of 8th grade Science (middle of
January until now). As you can see, this involves a lot of material, so you should prepare well in advance for
the test and use the following study guide to help guide your study. Remember this is just a guide, not a study
sheet. Do not wait until the last moment to begin your preparation for the exam. The sooner you begin the
more successful you will be. So study hard and good luck on your final exams. If you would like to check out
a textbook please come and see me.
We will go over this guide in class on (Monday, May 28 A-day) & (Tuesday, May 29 B-day). In order
to have the benefit prize for your final the review MUST BE COMPLETED on the day your guide is due.
Please come and see me if you have any questions!!
Chapter 20 The Energy of Waves
Key Terms: wave, medium, transverse waves, longitudinal waves, amplitude, wavelength, frequency,
wave speed, reflection, refraction, diffraction, interference, resonance
Key Concepts
1. What is a wave? Any disturbance that transmits energy through matter and space.
2. What is a medium? A substance through which a wave can travel.
3. What is the difference between a mechanical wave and an electromagnetic wave? Mechanical waves
need a medium and an electromagnetic wave does not require a medium.
4. How do particles vibrate in a transverse wave? Perpendicular to the rest position
5. How do particles vibrate in a longitudinal wave? Back and forth along the path that the wave travels
6. How do wavelength and frequency relate to each? They have an inverse relationship. If one increases
the other decreases.
7. What is the equation used to calculate wavelength, frequency and velocity? v=λ x f
8. What is the Greek letter used to express wavelength? lambda
9. What is wave speed and how is it calculated? It is the speed at which a wave travels. It can found by
measuring a single crest or compression distance traveled in a specific amount of time.
10. How is sonar an application of reflection? Sonar locates objects by transmitting waves. That wave then
reflects off of object and sent back in order to locate it.
11. What is the difference between constructive and destructive interference? In constructive interference,
the waves’ amplitude increases. In destructive interference, the waves’ amplitude decreases.
12. What is an example of resonance? Instruments, glass shaking in a car with a stereo turned up, objects
vibrating if a fast car passes by
Chapter 21 The Nature of Sound
Key Terms: Pitch, infrasonic, ultrasonic, Doppler effect, loudness, decibel, echolocation, shock wave, sonic
boom, noise
Key Concepts
1. How does the speed of sound change in different mediums? The speed of sounds slows as the density of
a medium decrease. The fewer molecules to vibrate, the slower the sound wave.
2. How is pitch measured? frequency
3. What is the range of frequencies that the human ear can hear? 20Hz to 20,000 Hz
4. What happens to frequency as an object moves toward you due to the Doppler effect? The pitch
increases as the moving object moves closer to you.
5. How is loudness measured? decibel
6. What are some common applications of echolocation? Bats hunting mosquitoes at night, echolocation,
ultrasounds
Chapter 22 The Nature of Light
Key concepts: electromagnetic spectrum, radiation, absorption, scattering, transmission
Key concepts include:
1. What is the law of reflection? The angle of incidence equals the angle of reflection.
2. What makes waves different in the electromagnetic spectrum? The difference in frequency and
wavelength.
3. What are the characteristics of the different waves in the electromagnetic spectrum? Microwaves are
used in radar. Infared waves are heat waves. Visible light are the colors that we see. Ultraviolet light
helps kill bacteria and causes skin cancer. X rays do not penetrate bones so they are used to create
images of bones in our bodies. Gamma rays are extremely dangerous and are used to kill cancer
cells.
4. Where is the visible spectrum in the electromagnetic spectrum? In the middle
5. What is the difference between transparent, translucent and opaque? Transparent allows all light to
transmit, translucent allows some light to transmit and opaque allows no light to transmit.
6. What are the primary colors? Red, blue and green
7. Why would I see a red shirt? Red is reflected back to my eye and the rest of the visible spectrum is
absorbed.
8. What is black? All colors are absorbed.
9. What is white? All colors are reflected.
10. What are the three primary pigments? Yellow, cyan and magenta
Chapter 23:2 Mirrors and Lenses
Key Concepts:
1. What is the difference between mirrors and lenses? Mirrors reflect light and lenses transmit light.
2. What is the difference between concave and convex? Concave curves away from you and convex
curves toward you.
3. What does a plane mirror look like and how does your reflection appear? Upright and virtual
Chapter 10 Heat and Heat Technology PS 7 a, b, c, d Temperature scale, heat, and heat transfer
Key terms: temperature scales, heat, temperature, thermal energy, heat technology, conduction, radiation,
convection, thermal pollution, conductors and insulators
Key Concepts
1. What are the three temperature scales that can be used? Fahrenheit, Celsius, and Kelvin
2. Using the three temperature scales, list the freezing point, boiling point and normal body temperature on
each scale. Fahrenheit: freezing 32°, boiling 212°, body 98.6° / Celsius: freezing 0°, boiling 100°,
body 37° / Kelvin: freezing 273, boiling 373, body 310
3. What is absolute zero? When all molecular movement ceases = 0 K (no degree sign)
4. What is thermal expansion? When molecules gain energy and begin to spread apart from each other and
take up more room
5. How are heat and thermal energy related? Heat is the transfer of thermal energy.
6. Name the three types of energy transfer and give an example of each. Conduction such as a pan
touching the burner on a stove, radiation such as a person being warmed by the radiation waves from a
fire , convection such as the currents in a heated pool
7. Give an example for a conductor and and an insulator. Conductor examples are metals and Insulator
examples are plastic, rubber, and glass
8. Name the three states of matter and describe the particle movement of each. Solids have particles that
are tightly packed together and vibrate in place, Liquids have particles that have enough energy to slide
past each other but are still experiencing some attraction between particles, Gases have particles that
move independently of each other
9. What is a heat engine and give an example of one. A heat engine is a machine that used heat to do
work, such as an internal combustion engine in our cars
10. Give an example of thermal pollution. The heated water from a nuclear/coal power plant that needs to
be cooled
Chapter 2:2 Properties of Matter—Describing Matter (PS 2 Properties of Matter
Key terms: physical property, chemical property, physical change, chemical change
Key Concepts
1. Give examples of physical properties. Color, density, texture, odor, malleability, ductility, appearance,
solubility, state of matter
2. Give examples of chemical properties. Flammability and reactivity
3. Is there a change in identity when observing physical changes? No What about when observing
chemical changes? yes
4. Name examples of physical changes. and Name examples of chemical changes.
Physical: melting butter, tearing paper, dissolving sugar into water, crushing a tablet, bending a
paperclip
Chemical: soured/spoiled milk/food, an alka seltzer tablet bubbling/fizzing in water, a car bumper
rusting
Chapter 4 Elements, Compounds, and Mixtures PS 2 a,b,c Investigate and understand the basic nature of
matter
Key terms: the particle theory of matter, elements, compounds, mixtures, solutions, suspensions, colloids,
solute, solvent, soluble, solubility, concentration, dilute, saturated
Key Concepts
1. Give examples of elements, compounds, and mixtures. Elements: gold, lithium, hydrogen / Compounds:
NaCl, H2O, Li2CO3 / Mixtures: sugar water, salad dressing, cool whip
2. Name the three major categories of elements. Metals, nonmetals, metalloids
3. Describe how to separate compounds and mixtures. Compounds may be able to be separated chemically
and mixtures can be separated physically
4. What is the Universal Solvent? water
5. What are the characteristics and properties of solutions, suspensions, and colloids?
Solutions have an amount of solute dissolved into the solvent, do not scatter light or separate, and
look homogeneous. Suspensions scatter light, can settle or separate, and look heterogeneous.
Colloids scatter light.
6. Give examples of solutions, suspensions and colloids. solutions such as sugar water or kool aid/
suspensions such as Italian dressing and medicines you have to shake up or your blood / colloids such as
cool whip, smog or fog
7. What is the difference between concentrated and diluted? Concentrated means it has a large amount of
solute compared to the solvent and diluted has a small amount of solute compared to the solvent. Think
about “weak” or diluted lemonade vs “strong” or concentrated lemonade.
8. Name methods to increase solubility. Stir, crush, add thermal energy
9. What is the difference between saturated and unsaturated solutions? Saturated means the solvent is holding
all the solute it can at that temperature (if you add more solute, it won’t dissolve) and unsaturated means it is
not holding all the solute it can at that temperature (you could add more solute and it would dissolve)
Chapter 11 Introduction to Atoms PS 3 a, b Modern and historical models of atomic structure
Key terms: proton, neutron, electron, atomic number, atomic mass, mass number, isotope
Key Concepts:
1. What were the contributions of Dalton, Thomson, Rutherford, and Bohr in constructing the modern model
of the atom?
Dalton – substances are made of atoms, which are the smallest particles of matter and can’t be divided,
atoms of the same element are identical and different from other elements, atoms can be combined in
specific amounts to make new substances
Thomson – determined that there were small, negative pieces (electrons) in the atom and thought they were
surrounded by positive material (plum pudding model)
Rutherford – determined that there is a positively charged center to the atom (nucleus with protons) and that
the electrons travel in a lot of empty space around the nucleus
Bohr – suggested that the electrons travel around the nucleus in definite paths, but the electrons can move
from path to path
2. State the charge and location of protons, neutrons, electrons. Protons are positive particles located in the
nucleus with the neutrons, which are neutral particles. Electrons are negative particles that travel in the electron
clouds surrounding the nucleus.
3. How do you calculate the mass of an isotope and name it? To calculate the isotope’s mass, you add the
atomic number and the number of neutrons in the nucleus. This is called the mass number and is used when
naming the isotope. An example is: C-12 or C-14. Both would have the same number of protons since they are
both Carbon! C-12 has 6 protons and 6 neutrons, but C-14 has 6 protons and 8 neutrons.
4.
What is the atomic mass unit (amu) of a proton, neutron, and electron? Protons and neutrons both have
an amu of 1 ech. Electrons are so tiny (about 1/1800 of the size of a proton!) that they aren’t assigned an atomic
mass.
5.
How do you determine the atomic number and atomic mass of an element? The atomic number and
atomic mass are both stated on the periodic table. Since the atomic number is based only on the number of
protons, it will always be the smaller of the two numbers in an atomic block on the periodic table. Since the
atomic mass is an average, it usually is listed as a number in decimal format, but not always.
Chapter 12 The Periodic Table PS 4 a, b Organization and use of the Periodic table of elements
Key terms: atomic symbol, period (row), chemical group/family (column), ion, isotopes
Key Concepts:
1. Describe how elements were arranged in the periodic table by Mendeleev and Moseley. Mendeleev
arranged the Table by increasing atomic mass, but Moseley arranged the Table by atomic number.
Mendeleev is considered the “Father” of the Periodic Table.
2. Describe metals, nonmetals, and metalloids based on their properties and location in the periodic table.
Metals are solids at room temperature (except for mercury), have few valence electrons, are shiny, malleable
and ductile and good conductors. They make up the majority of the periodic table and are listed on the “left
side” of the table. Nonmetals are found on the “right side” of the periodic table, most are gases at room
temp, most have almost full valence shells, they are not good conductors, and they are not malleable or
ductile. Along the “stair step” on the table are the metalloids, which are also called semiconductors. They
have some properties of both metals and nonmetals.
3. Describe the difference between a period and group and what information can be obtained from each’s
number. A period is a row on the periodic table and the period number is the number of energy levels/shells
the atoms in that row all have. A group (or family) usually has similar chemical and physical properties. A
group number is used to determine the number of valence electrons the atoms in that family have in order to
determine how it will bond with other atoms. This works for Groups 1 (1 valence electron) and Group 2 (2
valence electrons) and Groups 13-18 (subtract 10 from the Group number and that’s how many valence
electrons those atoms have).
4. Describe Bohr models and how many electrons can fit into each shell. Bohr models are models that show
the number of electrons in each energy level/shell of the atomic model. The first shell can hold up to 2
electrons (full at 2). The 2nd shell can hold up to 8 electrons (full at 8). The 3rd shell can hold between 1-8
(full at 8) or a total of 18 electrons.
5. What are the names of the different Groups/Families on the Periodic Table? Group 1 – Alkali Metals,
Group 2 – Alkaline Earth Metals, Groups 3-12 – Transition Metals, Groups 13-16, BCNO Groups (Boron
Family, Carbon Family, Nitrogen Family, Oxygen Family, Group 17 – Halogens, Group 18 – Noble Gases
6. What is special about the elements in Group 18? They are inert gases and don’t want to bond.
7. What is the difference between a chemical symbol, chemical formula, and chemical equation? A symbol is
the single/double letter that identifies an element, a chemical formula represents how many atoms of each
element are needed to make a molecule, and a chemical equation shows how many molecules of each
substance are needed to make new substances.
8. What is an ion? How do you write an ion’s charge? Show the ionic representation for Nitrogen, Sulfur,
Sodium and Magnesium. An ion is an atom that has gained/lost electrons and is no longer a neutral atom.
If an atom has gained electrons, it becomes negative (N -3 or S-2) and if it loses electrons it becomes positive
(Na+1 or Mg +2).
Chapter 13 Chemical Bonding
PS 4 c simple compounds (formulas and nature of bonding)
Key concepts include:
1. Binary Compounds:
o Chemical activity
o Physical properties
o Formulas
o Nature of bonding
* Be familiar with the following ideas and concepts:
1. What is the joining of atoms to form a new substance? Chemical Bonding
2. How can you identify the valence number for atoms? By the Family (Group) number
3. How an atom is likely to bond? By bonding with another atom or atoms to fill its outer valence shell with 8
electrons
4. Why does an atom want to bond? Because it is unstable
5. Describe ionic, covalent, and metallic bonding.
Ionic bonding is between a metal and non-metal by transferring electrons and forms a compound
Covalent bonding is between a non-metal and a non-metal by sharing and forms a molecule
Metallic bonding is between a positively charged metal ion and the electrons in a metal.
6. What is the difference between a compound and a molecule? A compound forms as a result of ionic
bonding and a molecule forms as a result of covalent bonding.
7. Define the terms malleability and ductility. Malleability is the ability of a substance to be pounded into thin
sheets and ductility is the ability of a substance to be drawn or pulled into a wire.
8. What are diatomic molecules? A molecule consisting of two atoms of a molecule bonded together. Oxygen,
nitrogen and the halogens, fluorine, chlorine, bromine, and iodine are diatomic molecules.
9. What are oxidation numbers? The number of electrons an element wants to gain, lose, or share.
10. What is the proper placement of electrons in an electron dot model?
2,6
3,7 S 1, 5
4, 8
11. What is a crystal lattice and which type of bonding does it occur in? In an ionic compound the ions form in
a repeating three-dimensional pattern called a crystal lattice.
Chapter 14 Chemical Reactions
PS 5 c Concepts of the Law of Conservation of Matter and Energy
Key concepts include:
1. chemical changes
a. types of reactions
b. reactants and products
c. balanced equations
* Be familiar with the following ideas and concepts:
1. What are four clues of a chemical reaction? Precipitate formation (solid is formed), gas formation
(bubbles), color change, and energy given off (exothermic or endothermic).
2. How do you write chemical formulas of ionic, polyatomic, and covalent bonds?
Ionic – criss-cross method
Polyatomic – criss-cross method
Covalent bonds – Look at the prefixes in the name to determine the subscripts in your formula
3. How do you name chemical formulas of ionic, polyatomic, and covalent bonds?
Ionic – First element name (plus Roman numerals if has one on the oxidation chart) plus the final element
name. Drop the final element’s ending and add –ide.
Polyatomic – Same as ionic bonds except when a polyatomic ion is present look up the name on the
oxidation chart and name the compound in the order of its ions.
Covalent bonds – Prefixes are added to every element except if the first element has a subscript of ‘1’, there
is no prefix. If the last part of the molecule is a single atom ion, add –ide to the ending.
4. How do you balance chemical equations? You multiply a coefficient by the subscript of each of the element
in the formula. If the product side does not equal the reactant side, use only coefficients to balance the
equation.
5. Explain the relationship between balancing equations and the Law of Conservation of Matter (Mass).
Mass is neither created nor destroyed in ordinary chemical and physical changes, therefore, the total mass of
the reactant side of a chemical equations must equal the total mass of the product side of a chemical
equation.
6. What are the four types of chemical reactions? Synthesis reactions, decomposition reaction, singlereplacement reaction, and double-replacement reactions.
7. Identify the following chemical reactions as related to type.
a. FeS + 2HCl → FeCl2 + H2S
Double replacement
b. NH4OH → NH3 + H2O
Decomposition
c. 2Mg + O2 → 2H2O
Synthesis
d. N2H4 + O2 → N2 + 2H2O Single replacement
8. Explain endothermic and exothermic reactions. Endothermic reactions energy is absorbed and in
exothermic reactions energy is released.
9. What is activation energy? The minimum amount of energy needed for substance to react is called
activation energy.
10. What are four factors that affect the rate of a chemical reaction? Temperature, concentration, surface area,
and the presence of a catalyst or inhibitor
11. What is the difference between inhibitors and catalysts? An inhibitor is a substance that slows down or
stops a chemical reaction. A catalyst is a substance a substance that speeds up a reaction without being
permanently changed.
Chapter 15:2 Acids, Bases, and Salts
PS 2 b Investigate and understand the basic nature of matter
Key concepts include:
1. acids, bases, and salts
* Be familiar with the following ideas and concepts:
1. Describe the properties and uses of acids and bases.
Acids – are corrosive to body tissue and clothing. Many are poisonous. Taste sour. Conduct an electric
current. Acids increase the number of hydrogen ions when dissolved in water. Some uses are used in the
production of metals, paper, paint, detergents, and fertilizers. They are used in car batteries and the keep
algae out of swimming pools.
Bases – feel slippery, taste, bitter, bases increases the number of hydroxide ions when dissolved in water.
Some uses of bases are making soap, paper, used in oven cleaners, and to unclog drains. Bases are also used
to make cement and mortar.
2. Explain the difference between strong acids and bases and a weak acid and base. In strong acids all the
molecules of an acid break apart in water to produce hydrogen ions. In weak acids a few molecules of an
acid break apart in water to produce hydrogen ions. In a strong base all the molecules of a base break apart
in water to produce hydroxide ions. In a weak base only a few molecules of a base produce hydroxide ions
in water.
3. Identify acids and bases using the pH scale and litmus paper.
pH scale - pH scale 0 to 6 is weak to strong acid and 8 to 14 is a weak to strong base. 7 is neutral on the pH
scale.
Litmus paper -- Acids turn blue litmus paper red.
Bases turn red litmus paper blue.
4. Describe the properties and uses of salts. A salt is an ionic compound formed from the positive ion of a
base and the negative ion of an acid. Salts are used to season foods, to make wall-board, in construction, to
make chalk and seashells, and preserving foods.
5. Explain the concept of neutralization. Neutralization is the combining of an acid with a base to produce a
salt.