Worksheets8th grade science semester 1 review
Total questions: 70
Worksheet time: 49mins
Name
Class
Date
1.
Why should an experiment be repeated?
a)
to form a hypothesis
b)
to reduce the chance of error
c)
to change controls
d)
to identify the problem
2.
The difference between a hypothesis and a theory is that a hypothesis is
a)
never true whereas a theory is always true.
b)
true whereas a theory is not true.
c)
never true whereas a theory is sometimes true.
d)
an educated guess whereas a theory has been tested successfully many times in many ways.
3.
Which of these is a scientific hypothesis?
a)
Atoms are the smallest particles of matter that exist.
b)
Albert Einstein is the greatest physicist of the twentieth century.
c)
The universe is surrounded by a second universe, which cannot be seen.
4.
Which of the following is a reason to express scientific findings mathematically?
a)
The findings become more difficult to prove by experiment.
b)
The findings become easier to verify by experiment.
c)
The findings become more confusing.
d)
The findings become less appealing to the public.
5.
Which question can best be investigated by a scientist?
a)
Should I buy a red shirt or a green shirt?
b)
Does chocolate milk or plain milk taste better?
c)
Does a plant need sunlight to grow?
d)
Which feels softer, cat fur or dog fur?
6.
This is the outcome of the experiment. We get data and results from this.
a)
Independent Variable
b)
Dependent Variable
c)
Control
d)
Constant
7.
How many independent variables should be tested at a time in a scientific investigation?
a)
none
b)
one
c)
two
d)
three
8.
The variable that is changed on purpose is:
a)
Control
b)
Dependent
c)
Independent
d)
Outcome
9.
A law is better than a theory.
a)
True
b)
False
10.
Laws tells us that it happens but doesn’t describe how or why.
a)
True
b)
False
11.
A theory ________ becomes a law.
a)
sometimes
b)
always
c)
never
12.
A scientific theory is proven true through experiments and observations.
a)
True
b)
False
13.
When a chemical change occurs, the products have a greater mass than the reactants.
a)
True
b)
False
14.
The change in the color of tree leaves in fall is an example of a physical change.
a)
True
b)
False
15.
In a neutral atom, the number of protons is equal to the number of electrons.
a)
True
b)
False
16.
Gamma decay emits energy but no particles.
a)
True
b)
False
17.
An alpha particle is the equivalent of a Helium-4 nucleus.
a)
True
b)
False
18.
Isotopes are forms of an element that have the same number of protons but a different number of neutrons.
a)
True
b)
False
19.
Greek philosophers thought that matter was composed of four elements: air, earth, fire, and water.
a)
True
b)
False
20.
Nuclear decay can change one element into another one.
a)
True
b)
False
21.
Which is a compound?
a)
sodium
b)
sea water
c)
carbon dioxide
d)
brass
22.
According to the Law of Conservation of Mass, in any chemical change
a)
the mass of reactants is greater than the mass of products
b)
the mass of reactants is less than the mass of products
c)
the mass of reactants is equal to the mass of products
d)
the masses of products and reactants have no predictable relationship
23.
Which of the following substances is an element?
a)
Baking Soda
b)
Iron
c)
Salt
d)
Sugar
24.
A chemical composition of two or more different elements joined together in fixed proportions is known as a(n) ____.
a)
compound
b)
element
c)
homogeneous mixture
d)
heterogeneous mixture
25.
What is the Atomic mass?
a)
Atomic Mass = A
b)
Atomic Mass = B
c)
Atomic Mass = C
d)
Atomic Mass = D
26.
Which is the Element Symbol?
a)
Element Symbol = A
b)
Element Symbol = B
c)
Element Symbol = C
d)
Element Symbol = D
27.
Which is the atomic number?
a)
Atomic Number = A
b)
Atomic Number = B
c)
Atomic Number = C
d)
Atomic Number = D
28.
Which one is comprised of the other three?
a)
proton
b)
atom
c)
electron
d)
neutron
29.
Which is the state of matter that has a definite shape and definite volume?
a)
Solid
b)
Liquid
c)
Gas
30.
Which is the state of matter that has an indefinite shape and definite volume?
a)
Solid
b)
Liquid
c)
Gas
31.
Which is the state of matter that has an indefinite shape and indefinite volume?
a)
Solid
b)
Liquid
c)
Gas
32.
Which is NOT a chemical change?
a)
a piece of wood is burned
b)
an egg is cooked
c)
a bar of iron rusts
d)
ingredients for a cake are stirred together
33.
How many electrons are in an neutral atom of sodium?
a)
22
b)
11
c)
12
d)
23
34.
Which of the following models best demonstrates a balanced chemical equation?
a)
F
b)
G
c)
H
d)
J
35.
How many atoms in all are in a molecule of serotonin?
C10H12N2O
a)
22
b)
24
c)
25
d)
4
36.
What are the reactants in the chemical equation pictured?
a)
CH4 and CO2
b)
CH4 and O2
c)
CO2 and H2O
d)
O2 and H2O
37.
What are the products of the chemical reaction pictured?
a)
CH4 and CO2
b)
CH4 and O2
c)
CO2 and H2O
d)
O2 and H2O
38.
What is the large number written before a chemical formula called?
a)
Coefficient
b)
Subscript
c)
Reactant
d)
Product
39.
What is a shorthand notation that represents a compound or molecule called?
a)
Chemical Equation
b)
Chemical Formula
c)
Chemical Reaction
d)
Chemical
40.
Balance this equation.
_CH4 + _O2 --> _CO2 + _H2O
_CH4 + _O2 --> _CO2 + _H2O
a)
1,2,1,1
b)
2,1,2,1
c)
1,2,1,2
d)
0,2,0,2
41.
Balance this equation.
_Mg + _Cl2 --> _MgCl2
_Mg + _Cl2 --> _MgCl2
a)
1, 2,1
b)
already balanced
c)
2,1,1
d)
1,1,2
42.
At the end of chemical reactions, what is the total mass of the reactants compared to the total mass of the products?
a)
the product is doubled
b)
the product is half the mass of the reactants
c)
the mass is the same
d)
the mass changes depending on the reaction
43.
Climate change causes extreme weather conditions such as:
a)
excessive heat
b)
drought
c)
extreme storms
d)
all of these
44.
Industrialization is a contributing factor to climate change.
a)
True
b)
False
45.
Increasingly severe weather systems such as monsoons or drought could lead to military conflicts.
a)
True
b)
False
46.
What is the greenhouse effect?
a)
The warming of a planet due to trapped radiation.
b)
The cooling of Earth due to air pollution.
c)
The heating of a solid, such as a rock.
47.
What do scientists think the effect will be of having more greenhouse gases in our atmosphere?
a)
More warming of the atmosphere
b)
More cooling of the atmosphere
c)
More air in the atmosphere
d)
Less air in the atmosphere
48.
Which of the following are greenhouse gases?
a)
Carbon dioxide
b)
Methane
c)
Water vapor
d)
All answers are correct
49.
What type of waves get trapped inside the greenhouse?
a)
Sunlight
b)
Ultraviolet
c)
Microwaves
d)
Infrared
50.
What is climate?
a)
Temporary conditions
b)
Small area conditions
c)
Long-term conditions
d)
Rapidly changing conditions
51.
Which of the following gases, released by animals as a waste product of digestion, can add to global warming?
a)
Carbon Dioxide
b)
Methane
c)
Chlorofluorocarbon
d)
Nitrogen
52.
As greenhouse gases increase, oceans are becoming
a)
clearer
b)
saltier
c)
more acidic
d)
muddier
53.
Melting of glaciers and polar ice caps....
a)
will result in cooler temperatures in the Arctic
b)
will result in sea-levels rising
c)
Will have no effect on ecosystems
d)
None of the above
54.
What is the average weather for a particular time and region called?
a)
drought
b)
weather
c)
emissions
d)
climate
55.
How do scientists collect evidence about climate?
a)
using remote sensing from space with satellites
b)
by ground-based measurements of surface temperatures, carbon dioxide concentration and sea level
c)
by collecting “proxy data” from tree rings, ice cores, and historical records
d)
all of the above
56.
Which of the following have been linked to climate change?
a)
droughts
b)
flooding
c)
melting of polar ice caps
d)
all of the above
57.
How much of Earth's freshwater is available for use?
a)
97%
b)
3%
c)
2%
d)
1%
58.
What is the energy source for the water cycle?
a)
the sun
b)
the earth
c)
water
d)
the moon
59.
What is evaporation?
a)
The part of the water cycle when the sun heats up water, turning it from a liquid into water vapor or steam. It rises from the ground into the air.
b)
The part of the water cycle when the water vapor in the air gets cold. The water turns back into a liquid and forms clouds.
c)
The part of the water cycle when clouds get heavy and can no longer hold the liquid water. This causes the water to fall from the sky to the earth as rain, snow, sleet, or hail.
60.
What is condensation?
a)
The part of the water cycle when the sun heats up water, turning it from a liquid into water vapor or steam. It rises from the ground into the air.
b)
The part of the water cycle when the water vapor in the air gets cold. The water turns back into a liquid and forms clouds.
c)
The part of the water cycle when clouds get heavy and can no longer hold the liquid water. This causes the water to fall from the sky to the earth as rain, snow, sleet, or hail.
61.
What is precipitation?
a)
The part of the water cycle when the sun heats up water, turning it from a liquid into water vapor or steam. It rises from the ground into the air.
b)
The part of the water cycle when the water vapor in the air gets cold. The water turns back into a liquid and forms clouds.
c)
The part of the water cycle when clouds get heavy and can no longer hold the liquid water. This causes the water to fall from the sky to the earth as rain, snow, sleet, or hail.
62.
Which is the opposite of condensation?
a)
runoff
b)
evaporation
c)
precipitation
d)
transpiration
63.
What is it called when plants give off water vapor as a waste product?
a)
condensation
b)
evaporation
c)
sublimation
d)
transpiration
64.
What is a layer of rock or sediment that holds water?
a)
glacier
b)
well
c)
aquifer
d)
natural spring
65.
How much of our planet's water is saltwater?
a)
75%
b)
1%
c)
99%
d)
97%
66.
What is the longest river in the WORLD?
a)
Amazon River
b)
Yellow River
c)
Colorado River
d)
Nile River
67.
What is a large, thick ice mass?
a)
iceberg
b)
glacier
c)
frozen lake
d)
ocean
68.
What is the longest river in the US?
a)
Missouri
b)
Mississippi
c)
Hudson
d)
Ohio
69.
What is density?
a)
mass
b)
mass/length
c)
mass/volume
d)
length/volume
70.
Which is better?
a)
Star Wars
b)
Star Trek
100 %
