8th Grade Science Alpha Benchmark Review Key€¦ · Web viewProperty - Proton - Reactant -...

8th Grade Science Alpha Benchmark Review Key

Define the following terms:

1. Acceleration -

2. Atom -

3. Balanced Forces -

4. Brittle -

5. Chemical Change -

6. Chemical Formula -

7. Compound -

8. Conductor -

9. Density -

10.Eclipse -

11.Electron -

12.Equinox -

13.Force -

14.Friction -

15.Galaxy -

16.Group (periodic table) -

17.Hertzsprung – Russel (H-R) diagram -

18.Hypothesis -

19.Inertia -

20.Insulator -

21.Law of Conservation of Energy -

22.Law of Conservation of Mass -

23.Lunar Phases -

24.Main Sequence -

25.Malleability -


26.Mixture -

27.Model -

28.Molecule -

29.Net Force -

30.Neutron -

31.Newton's 1st Law of Motion -

32.Newton's 2nd Law of Motion -

33.Newton's 3rd Law of Motion -

34.Nonmetal -

35.Nucleus (atom) -

36.Period (periodic table) -

37.Periodic Table -

38.Physical Change -

39.Property -

40.Proton -

41.Reactant -

42.Revolution -

43.Rotation -

44.Solstice -

45.Speed -

46.Star -

47.Tides -

48.Variable -

49.Velocity -

50.Volume -


Scientific Inquiry

Scientific Inquiry – Scientists ask questions about what they observe in the natural world. Inquiry guides research.

Theory – a possible explanation of observations and data, which is tested and revised.

Experiments – an experiment tests a hypothesis in a controlled setting, usually by changing one variable to see how it affects another variable. Experiments produce much of the data that make up modern science.

Steps in a Scientific Investigation

Ask Scientific Questions Form a Testable Hypothesis Design an Experiment to Test Hypothesis Select and Use Equipment and Technology Collect Data Analyze data and Form Conclusions Communicate Results Investigate Further

Laboratory and Field Terminology

Models – a model is a diagram or object that represents something and shows how it works.

Hypothesis – a proposed explanation to an answer.

Independent Variable – a variable that is changed to find how the change affects other variables in the experiment.

Dependent Variable – the variable or variables that are observed or measured in an experiment.

Laboratory and Field Experiments

Laboratory Equipment – should provide precise measurements. Tools can include a balance, meter stick, thermometer, graduated cylinder and stop watch.

Laboratory Safety – safety should always be an important concern in all experiments.

Experimental Group vs. Control Group – the “control group” is not subject to changes in the “independent variable”. Changes in the experimental group are then compared and contrasted to the control group.

Jillian wants to find out how the amount of fertilizer added to the soil affects plant growth. Which of these would be her independent variable?

a. how tall each of the plants growsb. the amount of fertilizer she adds to the

soilc. the size of pots in which the plants growd. the amount of water in each plant

In an experiment, a control –

a. is different in each of the items being tested.

b. is used to show the outcome of an experiment is due to the dependent variable.

c. contains all parts of an experiment except the independent variable.

d. contains all parts of an experiment except the dependent variable.


A man hypothesized that robins prefer large birdhouses to small ones. He built four birdhouses of different sizes to test his hypothesis. What was the independent variable in the man’s investigation?

a. The size of the birdhouseb. The number of birds in a housec. The location of the birdhoused. The season of the year

A scientist experimented with how long it took different amounts of water to boil. She boiled 100,200,400,800, and 1,600 g of water in the same pot. Between each trial, she let the pot and the burner cool to room temperature.

What was the independent variable in the study?

a. the size of the potb. the time needed to boilc. the temperature of the roomd. the mass of the water

A student designed an experiment to study how temperature affects the rate at which an enzyme digests a protein. She put equal masses of liver into four equal-sized test tubes, brought the test tubes to different temperatures, introduced equal amounts of enzyme to each tube, and measured the duration of the chemical reaction.

What parameters were held constant in the student’s investigation?

a. liver mass, enzyme amount, and reaction duration

b. liver mass, test-tube size, and enzyme amount

c. test tube temperature and reaction duration

d. test tube temperature, live mass and enzyme amount

Based on the information provided below, which of the following best describes that nutritional value of the hams?

a. Someone on a low-fat diet should choose Momma’s Ham.

b. Junior’s Ham tastes better than Momma’s

c. There are more preservatives in Junior’s Ham.

d. The amount of fat in ham will affect the amount of carbohydrates.

Momma’s Deli Ham

Junior’s Deli Ham


Nonmetals

Metals

Metalloids

Transition Metals

1. Shade in the Nonmetals, Metals and Metalloids on the table below.

2. Label the group names.3. Write the atomic number,

Symbol and Atomic Mass for the first 3 periods.

Find the protons, neutrons and electrons for fluorine, and then draw the Bohr model for fluorine.

Find the protons, neutrons and electrons for chlorine, and then draw the Bohr model for chlorine.

Fluorine Chlorine

9 P+

10 No17 P+

18 No

9 Protons10 Neutrons9 electrons

17 Protons18 Neutrons17 electrons


The diagram above shows the path that the moon takes as it revolves around the Earth. The outer drawing shows what the moon looks like from Earth. Notice that when there is a new moon, we only see the side of the moon that is in shade, which is why the moon is not visible from Earth during a new moon phase. Notice also that a small portion of the lit areas of the moon begins to appear after the new moon. The moon is increasing in size, during this part of the lunar cycle. The moon continues to wax until there is a full moon. After a full moon, the moon begins

Lunar Phases around Earth are responsible for the various phases of the moon.

Which of the illustrations to the right correctly depicts the movement of Earth and its moon?


The Movement of Earth

Gravity – gravity is a force of attraction between any two objects. Gravity governs the movements of the planets, moons, asteroids and comets in our solar system.

Earth’s Movement. Earth rotates on its axis, causing day and night.

o Earth revolves around the Sun.o The tilt of the Earth’s axis explains

the change of the seasons as Earth revolves around the sun. Diagram ADiagram ADiagram ADiagram ADiagram ADiagram ADiagram ADiagram ADiagram ADiagram ADiagram ADiagram ADiagram ADiagram ADiagram A

Diagram A illustrates the Earth’s orbit around the sun. At which point is it winter in the Southern Hemisphere?

a. Ab. Bc. Cd. D

Diagram A illustrates the Earth’s orbit around the sun. At which point is it spring in the Northern Hemisphere?

a. Ab. Bc. Cd. D

As seen from Earth, the moon changes from a full moon and back to a full moon each –

a. yearb. seasonc. dayd. month

All of the following cause summer in the Northern Hemisphere except –

a. earth’s northern axis is pointed toward the sun

b. the sun’s rays strike the Northern hemisphere at a sharp angle

c. the sun’s rays strike the Northern hemisphere most directly

d. the Northern Hemisphere receives the sun’s rays for a longer period of time

If Earth were not tilted on its axis, there would be no-

a. change of seasons on Earthb. day or nightc. phases of the moond. eclipses

Which of the following lunar phases will occur directly after a full moon?

a. Waxing gibbousb. Waning gibbousc. Waxing crescentd. Waning crescent


Why is it difficult to see a new moon in the night sky?

a. Because the moon is in the Earth’s shadowb. Because the moon is in orbit underneath

the Earthc. Because the moon is hidden behind a layer

of cloudsd. Because the lit side of the moon is facing

away from Earth

A student looking at a lunar calendar sees that the moon will be in in its first quarter phase that evening. What phase will the moon enter into next?

a. Waxing gibbousb. Waning gibbousc. Waxing crescentd. Waning crescent

Examine the series of lunar phases below. Which of the following phases will occur next?

Which of these stars is the hottest?

a. Red starb. Yellow starc. Orange stard. Blue star

Magnitude refers to a star’s

a. Distanceb. Colorc. Temperatured. Brightness

The H-R Diagram is useful in studying all of these about a star except for its –

a. Brightnessb. Location in skyc. Temperatured. Magnitude

Which of the following is a piece of evidence to support the Big Bang Theory?

a. Blue Shiftb. Red Shiftc. Plasma shiftd. Convection Shift


Which element is modeled in the drawing?

a. Lithiumb. Sodiumc. Potassiumd. Magnesium

What is the mass number of the atom shown?

a. 11b. 12c. 22.99d. 23

Examine the portion of the periodictable shown to the left. What do all of these elements have in common?

a. They all have the same atomic mass

b. They are all highly reactive elements

c. They are all solids at room temperature

d. They all have 8 electrons in their outer shell.

Add the coefficients to each of the following equations so they obey the Law of Conservation of Mass.

4 Fe + 3 O2 2 Fe2O3 ____ Fe + 3 Cl2 2 FeCl3

4 Hg + ____ I2 2 Hg2I 2 C2H6 + 7 O2 6 H2O + 4 CO2

2 Al + 3 Cl2 2 AlCl3 2 BF3 + 3 Li2SO3 ____ B2(SO3)3 + 6 LiF

2 N2 + 5 O2 2 N2O5 2 (NH4)3PO4 + 3 Pb(NO3)2 ____ Pb3(PO4)2 + 6 NH4NO3

86Rn

(222)Neon

54Xe

131.29Neon

36Kr

83.80Neon

18Ar

39.948Neon

10Ne

20.179Neon


Read the list of statements. Place an X in front of each statement that is likely to demonstrate a chemical reaction.

_____ 1. An iron is left in the rain and is also exposed to air.

_____ 2. Slices of bread in a bag are allowed to sit in a warm, dark area.

_____ 3. Graham crackers are crushed for a pie crust.

_____ 4. A carrot is sliced for a salad.

_____ 5. A match is slid across the rough area of a match box.

_____ 6. Ice is left near a window on a sunny day.

_____ 7. During a shower, condensation forms on a bathroom mirror.

_____ 8. A stain is removed from a shirt after bleach is added to the wash.

What scientific law is being illustrated when you balance a chemical equation?

a. The Law of Reflectionb. The Law of Electric Chargesc. The Law of Conservation of Massd. The Law of Conservation of Energy

According to the Law of Conservation of Matter, the number of _______ is not changed by a chemical reaction.

a. productsb. bondsc. moleculesd. atoms

Which of the following is an example of a compound?

a. Clb. Nac. O2

d. H2O

Gerald's science teacher mixed room temperature samples of hydrochloric acid and sodium hydroxide in a large beaker. The solution still looked clear like water, but when the students carefully touched the beaker one at a time, it felt warm to the touch.

Why did the beaker most likely feel warm?

a. The two liquids were not soluble in water.b. A chemical reaction was producing a new

substance.c. The energy of mixing warmed the solution.d. The release of gas heated the solution.

Which of the following events always occurs during a chemical reaction?

a. The density of two or more substances changes.

b. Two or more substances react to form a new substance.

c. Enzymes act as catalysts to speed up the rate of reaction.

d. Electrons of two or more substances become excited and emit light.

X

X

X

X


Motion

Distance – Total length moved by an object Speed – Average distance traveled by a moving

object in a unit of time, such as m/sec or miles per hour.

Velocity – Speed in a particular direction

Speed=distancetime

Acceleration – change in the motion of an object.

Acceleration= final velocity−initial velocitytime

Force

Force – “Push” or “pull” causes an object to change its motion; measured in Newtons.

Amount of force needed to change the motion of a body is proportional to the body’s mass and speed of change.

Force=(mass)(acceleration)

Balanced vs. Unbalanced Forces – Balanced forced have no effect on an object’s motion. A force or group of forces that push more on one side than the other is “unbalanced” and causes a change in movement.

1. Any time you push or pull an object you are applying a force.

2. An object’s speed describes its rate of motion, or how fast it is moving.

3. When forces act on an object, they cause a change in the speed or direction of motion.

4. An object that is not moving is said to be at rest.

5. Even if an object’s motion is at rest, there are still forces acting on it. The forces on an object at rest or with unchanging motion are balanced .

What is the speed on runner A?

Speed=30cm30 s

Speed=10 cms

What is the speed on runner B?

Speed=35cm30 s

Speed=distancetime


Graph the following data on the chart, then answer the question.

Mass (g)

Volume (mL)

1 102 203 304 405 50

Draw a diagram that represents the sun, moon and Earth during a spring tide.

Draw a diagram that represents the sun, moon and Earth during a neap tide.

Describe what the following units measure.

1. m length

2. g mass

3. mL volume

4. cm3 volume

5. g/cm3 density

6. m/s2 acceleration

7. light years distance

1. An object’s velocity includes information about the direction of motion, but speed does not.

2. The object’s velocity is 2 m/s North.

3. When you calculate speed, you use distance and time

4. You need more force to accelerate when you have a larger mass.

5. Newton’s first law is also called the Law of inertia because it says that objects resist changes in their motion.

Volume (mL)

Mass (g)

Density of Liquid Alpha

How does the density of Liquid Alpha change when mass increases?

A. It increases by 10B. It decreases by 10C. It does not changeD. There is not enough

information to answer the question

Spring Tides occur during the full and new moons. Neap Tides occur during the 1st and 3rd Quarter moon.


1. What are subatomic particles, what are their charges, and where are they found?

2. How is the mass of an atom determined?

3. How do protons determine an element’s identity?

4. How do valence electrons determine an element’s chemical properties?

5. How are elements arranged on the Periodic Table?

6. What does an atom’s atomic number represent?

7. What do the columns on the periodic table represent and how is that information used?

8. What do the rows on the periodic table represent and how is that information used?

9. What happens to atoms in a chemical reaction?

10.What is a chemical formula?

11.What does it mean to “balance” a chemical equation and how does it relate to the Law of Conservation of Mass?


12.How do balanced and unbalanced forces affect an object’s motion?

13.What effect does friction have on an object’s motion?

14.How can you tell the difference between speed, velocity, and acceleration on a graph?

15.How can one determine speed or velocity of an object given distance and time?

16.How are speed, velocity, and acceleration represented on a distance vs. time graph?

17.What is the difference between speed and velocity?

18.What is the difference between velocity and acceleration?

19.How does the force required to move an object change with mass?

20.Describe Newton’s 3 Laws of Motion (give examples).


21.What is Earth’s axis and what is the degree of its tilt?

22.What is the difference between Earth’s rotation and revolution?

23.What causes day and night?

24.What causes the seasons?

25.How does the Sun affect moon phases?

26.What do the terms waxing and waning mean?

27.What effect does the gravitational pull of the Moon and the Sun have on Earth?

28.Why are we able to predict tides?

29.What is a high tide? A low tide?

30.What is a neap tide? A spring tide?


31.What is the Herztsprung-Russell Diagram, and how is it used to classify stars?

32.How does the Sun’s mass compare with other stars?

33.How does the distance of the Sun from Earth compare to the distances of other stars from Earth?

34.How do astronomers know that galaxies are moving away from Earth?

35.How do astronomers measure distance between galaxies and stars?

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