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Science 9 Second Semester Exam Review

Name _____________________
This exam review is worth 200 homework points. Each day check is 50 points. ALL OR
NOTHING! Checks will happen May 27th, 28th, 29th and the day of the exam.
There will be questions regarding types of Radiation on the Exam.



Alpha particles
 Made up of two protons and two neutrons
 Least penetrating form of ionizing radiation
 Reduces mass number of atom by four
 Reduces atomic number of atom by two
Beta particles
 Made up of an electron
 Produced when a neutron in the nucleus breaks down into a proton and electron
 Increases atomic number by one
 Does not change mass number
Gamma rays
 Most penetrating form of ionizing radiation
 Electromagnetic waves; not particles
 Does not change atomic number
 Does not change mass number

Half-life
 The amount of time it takes for half of a sample of unstable nuclei to give off radiation and become
another element

Practice:
1. What element is formed when Bismuth- 214 undergoes alpha decay?
210
81𝑇𝑙
2. What element is formed when Lead-210 undergoes beta decay?
210
83𝐵𝑖
3. Lead-210 has a half-life of 20 years. How much of a 100 gram sample remains after 60 years?
Total time
20 y
40 y
60 y
Number of
half-lives
Unchanged
material
0
1
2
3
100 g
1/2
50 g
1/4
25 g
1/8
12.5 g
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4. Iodine-123 has a half-life of 13.1 hours. (record your answers in the chart)
a) How much of 160 grams of Iodine-123 is left unchanged after five half-lives? 5 g
b) How much of the 160 grams has decayed into another element after five half-lives? 155 g
c) How much total time has passed in five half-lives of Iodine-123? 65.5 h
4.
Total time
Number of
half-lives
Unchanged
material
0
1
2
3
4
5
160 g
0g
1/2
80 g
80 g
1/2
1/4
40 g
120 g
3/4
1/8
20 g
140 g
7/8
1/16
10 g
150 g
15/16
1/32
5g
155 g
31/32
13.1 h
26.2 h
39.3 h
52.4 h
65.5 h
Decayed
material
Covalent bonding
A. chemical bonding between nonmetals
B. electrons are shared
1. single covalent bond- one pair of shared electrons
2. double covalent bond- two pair of shared electrons
3. triple covalent bond- three pair of shared electrons
C. attraction of nuclei to the shared electrons keeps the atoms close to each other
D. molecules are formed
Write the prefixes 1-10 for naming covalent bonding:
1=
2=
3=
4=
5=
monoditritetrapenta-
6=
7=
8=
9=
10=
hexaheptaoctanonadeca-
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Draw the covalent bond between the following using Lewis Dots and Structural Formulas. Also state how many
electron pairs each bond shares.
a. Hydrogen and Hydrogen-shares 1 pair
d. 2 Hydrogen and 1 Oxygen shares 1 pair
b. Chlorine and Chlorine shares 1 pair
e. 3 Hydrogen and 1 Phosphorus shares 1 pair
c. Carbon and 2 Oxygen
f. Carbon and 4 Hydrogen shares 1 pair
shares 2 pairs
Name the following compounds:
1. CO2
carbon dioxide
3. SiO2 silicon dioxide
2. CH4
carbon tetrahydride
4. NH3 nitrogen trihydride
Velocity and acceleration

Velocity (speed + direction)
 Distance = velocity
Time
Acceleration
 Final velocity – initial velocity = acceleration
Total Time
Practice:
1. What is the velocity of an object that travels a distance of 150 meters in 30 seconds?

𝑣=
𝑑
150 𝑚
=
= 5 𝑚/𝑠
𝑡
30 𝑠
2. What is the acceleration of an object that goes from 150 km/hr to 200 km/hr in 5 seconds?
𝑎=
𝑣𝑓 − 𝑣𝑖
200𝑘𝑚/ℎ𝑟 − 150𝑘𝑚/ℎ𝑟
=
= 10 𝑘𝑚/ℎ𝑟/𝑠
𝑡
5𝑠
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3. What is the acceleration of an object that goes from 200 km/hr to 175 km/hr in 5 minutes?
𝑎=
𝑣𝑓 − 𝑣𝑖
175𝑘𝑚/ℎ𝑟 − 200𝑘𝑚/ℎ𝑟
=
= −5 𝑘𝑚/ℎ𝑟/𝑚𝑖𝑛
𝑡
5 𝑚𝑖𝑛
4. An Olympic swimmer swims 50.0 meters in 23.1 seconds. What is his average speed?
𝑣=
𝑑
50.0 𝑚
=
= 2.16𝑚/𝑠
𝑡
23.1 𝑠
5. A plane’s average speed between 2 cities is 600 km/hr. If the trip takes 2.5 hours, how far does the plane
fly?
𝑣=
𝑑
𝑡
600𝑘𝑚/ℎ𝑟 =
𝑑 = 1500 𝑘𝑚
𝑑
2.5 ℎ𝑟
6. A ball rolls down a ramp, starting from rest. After 2 seconds, its velocity is 10 meters/second. What is the
acceleration of the ball?
𝑎=
𝑣𝑓 − 𝑣𝑖
10𝑚/𝑠 − 0𝑚/𝑠
=
= 5𝑚/𝑠 2
𝑡
2𝑠
7. A car traveling at 10 m/s starts to decelerate steadily. It comes to a complete stop in 20 seconds. What is its
acceleration?
𝑎=
𝑣𝑓 − 𝑣𝑖
0 𝑚/𝑠 − 10 𝑚/𝑠
=
= −0.5𝑚/𝑠 2
𝑡
20 𝑠
8. An airplane travels down a runway for 4.0 seconds with an acceleration of 9.0 m/s2. What is its change in
velocity during this time?
𝑎=
∆𝑣
𝑡
9.0𝑚/𝑠 2 =
∆𝑣
4.0𝑠
∆v = 36 𝑚/𝑠
Energy

Potential energy
 PE = mgh
 m = mass of the object (in kilograms)
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



g = force of gravity
g = 10 newtons/1 kilogram or 10 meters/sec2
h = height of object (in meters)
measured in joules

Kinetic energy
 KE = ½ mv2
 m = mass of object (in kilograms)
 v = velocity of object (in meters per second)
 measured in joules

Practice problems
1. A 100 kg object is lifted a distance of 10 meters. How much potential energy has the object
gained?
𝐸𝑔 = 𝑚𝑔ℎ = (100𝑘𝑔)(10𝑚/𝑠 2 )(10𝑚) = 10,000𝐽
2. A 100 kg object is moving at a velocity of 10 m/sec. How much kinetic energy does it
have?
𝐸𝑘 =
1
1
𝑚𝑣 2 = (100𝑘𝑔)(10𝑚/𝑠)2 = 5,000𝐽
2
2
For the following diagram, a 10 kg ball is being dropped from the height of 15 meters. At the height of
15 meters, the ball is at rest waiting to fall. Calculate the potential and kinetic energies at each height
indicated in the diagram.
PE = 1500J
KE = 0 J
PE = 1000J
KE = 500 J
PE = 500J
KE = 1000 J
PE = 0J
KE = 1500 J
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Momentum


Momentum = mass X velocity
Practice problems
1. The two objects shown below collide and stick together. Which direction will they be
traveling after the collision?
15 kg
A
2.
5 m/sec
75 kgm/s
4 m/sec
76 kgm/s
19 kg
B
The two objects shown below collide and come to a stop. What is the mass of Object
B?
100 kg
A
15 m/sec
25 m/sec
1500 kgm/s
60 kg
B
Electromagnetic waves
 Refraction
o Bending of light
o Caused as light changes speed passing from one type of material to another
o More pronounced when light hits surface of material at an angle other than 90°
o Convex lens
 Acts as two prisms set base to base
 Bends light to focal point
 Images seen can be magnified or upside down
o Concave lens
 Acts as two prisms set point to point
 Bends light away from center
 Images seen appear smaller

Reflection
o Angle of incidence = angle of reflection
o Concave mirror
 Curves inward
 Bend light to focal point
 Images appear magnified or upside down
o Convex mirror
 Curves outward
 Light bent away from center
 Images appear smaller
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Practice questions
12. What type of device is being shown here to the left?
a) concave lens
b) concave mirror
c) convex lens
d) convex mirror

13. The image seen with this device (question 12) would be:
a) life-size
b) magnified
c) smaller
d) upside down
----------------------------------------------------------------------------------------------------------14. What type of device is being shown here to the left?
a) concave lens
b) concave mirror
c) convex lens
d) convex mirror
15. The image seen with this device would be:
a) life-size
b) magnified
c) smaller
d) upside down
-----------------------------------------------------------------------------------16. What type of device is being shown here to the left?
a) concave lens
b) concave mirror
c) convex lens
d) convex mirror
17. The image seen with this device would be:
a) life-size
b) magnified
c) smaller
d) upside down
------------------------------------------------------------------------------------------------18. What type of device is being shown here to the left?
a) concave lens
b) concave mirror
c) convex lens
d) convex mirror
19. The image seen with this device would be:
a) life-size
b) magnified
c) smaller
d) upside down
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Given the equation: Speed= Wavelength X Frequency calculate the following:
1. What is the speed of a wave that has a frequency of 4.0 Hz and .50 m. Give the answers in
meters/second
s = f = (0.50m)(4.0Hz) = 2 m/s
2. Wavelength: 3 m, Frequency: 1.5 Hz
s = f = (3 m)(1.5 Hz) = 4.5 m/s
3. A wave on a rope has a frequency of 3.3 Hz and a wavelength of 1.2 meters. What is the speed of the
wave?
s = f = (1.2 m)(3.3 Hz) = 3.96 m/s
4. What is the wavelength of an earthquake wave if it has a speed of 5 km/s and a frequency of 10 Hz?
s = f
5 km/s =  (10hz)
 = 0.5 km
5. A wave on a rope has a wavelength of 2.0 m and a frequency of 2.0 Hz. What is the speed of the
wave?
s = f = (2.0 m)(2.0 Hz) = 4.0 m/s
Electricity
Circuit A
Circuit B
Circuit C
Simple
Circuit
Circuit D
Circuit E
Circuit F
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1. List the parallel circuit(s).
B
D
F
2. List the series circuit(s).
A
C
3. Rank the circuits by bulb brightness, from brightest bulbs to dimmest bulbs. Use equal
signs if needed.
B
= D
= F
= E
C
A
The Universe
1. What is the sun’s energy produced by? ______fusion___________________________
2. In the next few billion years, what will happen to the amount of hydrogen in the sun?
____________The amount of hydrogen will decrease___________________________
3. In the next few billion years, what will happen to the amount of helium in the sun?
____________The amount of helium will increase____________
__________
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B
D
E
A
C
4. What is the approximate temperature of our sun? 6000K
5. Is the surface temperature of a red giant hotter or colder than a blue giant? colder
6. What is the color of the stars with the lowest surface temperature? red
7. Most of the stars on the HR diagram are considered? Main sequence
8. What type of star has low temperature low luminosity? Red main sequence
9. What type of star has low temperature high luminosity? Red super giant
10. List the color of the stars from coolest to hottest. Red, orange, yellow, white, blue
11. Fill in the chart below:
Letter
A
B
C
D
E
Temperature
6,000K
20,000K
20,000K
2,500K
4000K
Luminosity
10-1
106
10-2
106
102
Color
Color
Yellow/orange
Blue
White
Orange/Red
red
Type of Star
Main sequence
Blue giant
White dwarf
Red supergiant
Red giant
Star
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Fission & Fusion
1. What type of elements are more likely to undergo fusion? Why?
Lighter elements are more likely to undergo fusion because they have smaller nuclei that can fuse with
another nuclei and remain stable.
2. What type of elements are more likely to undergo fission? Why?
Heavier elements are more likely to undergo fission because they have larger unstable nuclei that have
a tendency to split to become more stable.
3. How do stars burn: fission or fusion?
fusion
10% of this exam will be material from the first semester
1. What are the atomic mass units for protons (1 amu), neutrons (1 amu), and electrons (0 amu)?
2. What is the atomic number? Number of protons
3. What is the mass number? Protons + neutrons
4. What particles are in equal numbers in a neutral atom? Protons = electrons in a neutral atom
5.
How is the number of protons determined? Protons = atomic number
6.
How is the number of neutrons determined? Mass # - Atomic # = neutrons
7. In a neutral atom, what two particles are equal to each other? Protons = electrons in a neutral atom
8. What subatomic particles are located in the nucleus? Protons and neutrons
9. How many electrons can be found in the first energy level of an atom? 2
10. How many electrons can be found in the second energy level of an atom? 8
11. What is the electron arrangement for a neutral atom? How many are found in each shell? 2-8-8-18
Complete the following diagrams and fill in the charts for each element. Use the periodic table as a reference.
5
5
11
6
2-3
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10
10
20
10
2-8
12. How are isotopes different from other forms of the same element? They have different mass
numbers and numbers of neutrons.
Periodic Table: Tell what column /row each will be in
13. Which elements have one valence electron? Group/column 1
14. Which elements have two valence electrons? Group/column 2
15. Which elements have three valence electrons? Group/column 13
16. Which elements have four valence electrons? Group/column 14
17. Which elements have five valence electrons? Group/column 15
18. Which elements have six valence electrons? Group/column 16
19. Which elements have seven valence electrons? Group/column 17
20. Which elements have eight valence electrons? Group/column 18
21. Which elements are alkali metals? Group/column 1
22. Which elements are alkaline earth metals? Group/column 2
23. Which elements are halogens? Group/column 17
24. Which elements are noble gases? Group/column 18
Identifying elements by period
25. Which elements have one electron shell? Period/row 1
26. Which elements have two electron shells? Period/row 2
27. Which elements have three electron shells? Period/row 3
28. Which elements have four electron shells? Period/row 4
29. Which elements have five electron shells? Period/row 5
30. Which elements have six electron shells? Period/row 6
31. Which elements have seven electron shells? Period/row 7
32. Which elements are metals? Left side of the periodic table
33. Which elements are nonmetals? Right side of the periodic table
34. Which elements are metalloids? On the red line (B,Si,Ge,As,Sb,Te,Po,At)
35. Which elements are transition metals? Groups/columns 3-12
*****This is a lot of information…Make sure you
complete this review and study!!!!!!!***** :)
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