Chemistry Unit Review Answer Key
1. Write the term next to its definition. Choose from these terms:
atom
chemistry
compound
element
group
heterogeneous
homogeneous
mixture
period
periodic
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
period - row on the periodic table
group - column on the periodic table
atom - smallest particle of matter
element - simplest form of matter
compound - 2 or more elements chemically combined
mixture - 2 or more substances physically combined
heterogeneous - mixture with individual parts visible
homogeneous - mixture that looks the same throughout
periodic - happens at a regular intervals
chemistry - the study of matter
2. What is Mendeleev known for? The Periodic Table of Elements
3. How is the periodic table organized? Elements are arranged in order of
increasing atomic number and mass as well as by similar properties
4. Fill out the missing information in the table shown below:
Atomic #
Element
Symbol
Group
Period
79
gold
Au
11
6
80
mercury
Hg
12
6
8
oxygen
O
16
2
5. For each of these labs, describe the evidence you observed showing that a
chemical reaction took place.
A. Chalk Lab formation of a precipitate
B. Science in a Bag Lab color change, temperature change, and production of
gas
6. Examine the pictures of mixtures shown below. Place a checkmark in the
correct space after deciding if each mixture is heterogeneous or homogeneous.
Pepperoni Pizza
Gravel (rocks)
Stainless Steel
X heterogeneous
___homogeneous
___heterogeneous
X homogeneous
X heterogeneous
___homogeneous
Oatmeal Raisin Cookie
X heterogeneous
___homogeneous
Vanilla Ice Cream
___heterogeneous
X homogeneous
Cookies and Cream
Ice Cream
X heterogeneous
___homogeneous
Cherry KoolAid
___heterogeneous
X homogeneous
Salt Water
___heterogeneous
X homogeneous
7. Identify the group, period, and characteristics for each of these elements.
a) He (helium) - Group 18
Characteristics: nonmetals, gas at room temperature
2 other elements in this same group: neon and argon
b) Ca (calcium) - Group 2
Characteristics: metals, solid at room temperature
2 other elements in this same group: barium and radium
8. Examine the pictures of substances shown below. Label each substance as
an element, compound or mixture.
a) element
b)compound
c)mixture
9. A compound has different properties than those of the elements used to
make it.
10. Write the term next to its definition. Choose from the terms in the box.
acid
element
homogeneous
solid
atom
base
compound
heterogeneous
liquid
molecule
neutral
mixture
soluble
gas
indicator
oxidation
precipitate
insoluble
states of matter
density
a) atom - smallest particle of matter
b) element - simplest form of matter
c) compound - 2 or more elements whose atoms have
chemically combined
d) mixture - 2 or more substances physically combined
e) heterogeneous - mixture with individual parts visible
f) states of matter - solid, liquid, gas
g) solid - definite volume and shape
h) liquid - definite volume, changeable shape
i) gas - changeable volume and shape
j) homogeneous - mixture that appears the same throughout
k) soluble - able to dissolve
l) insoluble - NOT able to dissolve
m) acid - pH less than 7, orange juice is an example
n) base - pH greater than 7, baking soda is an example
o) neutral - pH = 7, pure water is an example
p) oxidation - chemical reaction with oxygen
q) precipitate - new solid created from two clear liquids
11. What is the change in state for each of these phase changes?
a) melting – going from solid to liquid
b) evaporation - going from liquid to gas
c) condensation - going from gas to liquid
d) freezing - going from liquid to solid
12. Name an example of a solution: salt water
13. Answer these questions about acids and bases.
a) What is the pH range of acids? 1-6 bases? 8-14
b) What is the pH of a neutral solution? 7
14. Examine the following table, and then answer the questions below. Use
your periodic table, if needed.
Substance
aluminum
mercury
sodium
water
Boiling Point (°C)
2519
357
883
100
Melting Point (°C)
660
-39
98
0
a) Write the symbol of the substance with the highest boiling point. Al
b) Write the symbol of the substance with the lowest melting point. Hg
c) Which phase change is happening at the boiling point? evaporation
15. Identify the five ways you can know that a chemical reaction has taken
place.
a) Change in color
b) Change in temperature
c) Formation of a precipitate
d) Change in odor
e) Production of gas
16. Match these experiments to the evidence that a chemical reaction took
place. Put the letters (a-e) from the previous question (#15) in the
appropriate blank.
b vinegar and baking soda got colder
e hydrogen peroxide and yeast started bubbling
c combining two liquids produced chalk which is insoluble
a an iron nail rusts