WorksheetsChemistry Review for the 8th grade assessment
Total questions: 26
Worksheet time: 26mins
Name
Class
Date
1.
Many processes occur in the digestive system. Which process is best classified as a physical change?
a)
Saliva converting the starch molecules in crackers into simple sugars
b)
Digestive enzymes breaking down proteins into smaller fragments
c)
Bacteria converting lactose into simple sugars in the intestines
d)
Teeth grinding an almond into smaller pieces in the mouth
2.
Some students in a chemistry lab conducted an investigation in which they added four different solid substances to separate beakers of water. They stirred the mixtures for one minute and then recorded their observations in the table. Which substance most likely caused a new substance to be formed when mixed with water?
a)
Substance 1
b)
Substance 2
c)
Substance 3
d)
Substance 4
3.
Coal contains carbon and other elements. Carbon dioxide forms when coal burns in the presence of oxygen. Which of these is the best evidence that a chemical reaction occurs when coal burns?
a)
The shape f the coal changes.
b)
Oxygen is present.
c)
A new substance is produced.
d)
Coal is made up of more than one element.
4.
An atom of a certain element has 36 protons, 36 electrons, and a mass number of 84. At room temperature this element is a very stable gas. How many neutrons are in this atom?
a)
58
b)
72
c)
120
d)
48
5.
An atom has 25 protons, 30 neutrons, and 25 electrons. What is the charge of the atom's nucleus?
a)
+25
b)
+30
c)
-25
d)
-30
6.
positive charge, found in nucleus, mass = one
a)
proton
b)
neutron
c)
electron
d)
ion
7.
no charge, found in nucleus, mass = one
a)
proton
b)
neutron
c)
electron
d)
ion
8.
negative charge, found orbiting nucleus, mass is almost zero
a)
proton
b)
neutron
c)
electron
d)
ion
9.
Smallest component of an element
a)
atom
b)
molecule
10.
What classifies a substance as a mixture?
a)
Made up of two or more substances that are chemically bonded.
b)
One substance that can not be physically separated
c)
Two or more substances that are not chemically bonded.
d)
A substance that can not be seperated
11.
What cannot be broken down into other substances?
a)
Compound
b)
Mixture
c)
Solids
d)
Element
12.
Mixtures are separated through ___________changes.
a)
mixture
b)
compound
c)
physical
13.
An element is made up of only one kind of _____.
a)
isotope
b)
plastic
c)
atom
d)
metal
14.
the central region of an atom where its neutrons and protons are is its
a)
nucleus
b)
electron cloud
c)
core
d)
center
15.
When materials combine to form new compounds it is a chemical change. Which example is a chemical change?
a)
baking powder fizzing
b)
water boiling
c)
ice melting
d)
sugar cube dissolving
16.
If a Carbon atom has 6 protons, how many electrons will it have?
a)
2
b)
4
c)
6
d)
8
17.
_______ and _______ are located inside of the nucleus.
a)
Electrons and Protons
b)
Protons and Neutrons
c)
Neutrons and Electrons
18.
The elements in a column of the periodic table...
a)
have similar atomic numbers
b)
start with the same letter
c)
have similar properties
d)
are not related in any way
19.
Which group of elements have both metal and non-metal characteristics?
a)
lanthanides
b)
metalloids
c)
actinides
d)
noble gases
20.
A row on the periodic table of elements is called a...
a)
Period
b)
Group
c)
Family
d)
Column
21.
The amount of matter an object has.
a)
Weight
b)
Mass
c)
Volume
d)
Density
22.
Oil floats on water. The most accurate reason for this is ____.
a)
oil is less dense than water
b)
oil is immiscible (does not dissolve) in water
c)
oil is both less dense and immiscible with water
d)
water is heavier than oil
23.
______________ is the amount of space an object occupies.
a)
Weight
b)
Mass
c)
Volume
d)
Density
24.
Water changes its state of matter when heat is added or taken away. When water reaches its boiling point the particles-
a)
are closer together
b)
stay the same
c)
are moving more rapidly
d)
are moving more slowly
25.
Ability of one substance to dissolve in another.
a)
Mixture
b)
Solubility
c)
Melting Point
26.
What is the volume of the rock? The water level is displaced from 20 mL to 23 mL with the rock.
a)
3 mL
b)
23 mL
c)
20 mL
d)
43 mL
100 %
