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WORKSHEET
#1
Dougherty Valley HS Chemistry
Physical/Chemical Prop’s and ∆’es
1. A physical property is observed with the senses and can be determined without destroying the object.
Examples of physical properties include mass, shape, color, odor, length. In a physical change, the
original substance still exists. It has only changed form.
2. A chemical property indicates how a substance reacts with something else. In a chemical change, a
new substance is produced. Energy changes always accompany chemical changes. Chemical changes
are always accompanied by physical changes.
3. Which of the following processes are physical changes? Which are chemical changes?
a. combustion
e. evaporation
i. boiling
b. melting
f.
filtration
c. dissolving
g. fermentation
d. metabolism
h. distillation
j.
electrolysis
k. decomposition
Identify the following properties as physical or chemical.
Physical Chemical
Blue color
Density
Flammability
Solubility
Supports combustion
Sour taste
Melting point
Physical Chemical
Odor
Luster
Neutralize an acid
Boiling point
Hardness
Reacts with acid to form H2
Reacts with water to form a gas
4. Classify the following examples as physical or chemical changes.
a. Sodium chloride dissolves in water
______________________
b. Hydrochloric acid reacts with sodium hydroxide
______________________
to produce a salt, water, and heat.
c. A pellet of sodium is sliced in two pieces.
______________________
d. Water is heated and changed to steam.
______________________
e. Potassium chlorate decomposes to potassium
chloride and oxygen gas.
f. Iron rusts.
______________________
g. Ice melts.
______________________
h. Acid on limestone produces carbon dioxide gas.
______________________
i.
Wood rots.
______________________
j. cracking an egg
______________________
k. bake a cake
______________________
______________________
WORKSHEET #2
WORKSHEET ON CHEMICAL VS PHYSICAL
PROPERTIES AND CHANGES
Keep this in your binder as a study guide! You will have a quiz on this next class!
Background:
Keeping the difference between physical and chemical properties as well as changes can be a
challenge! This worksheet will help you do this. First, use the book to define the following terms.
VOCABULARY WORD
DEFINITION
Physical Property
Physical Change
Change in which the identity of the substance does NOT change
Chemical Property
Chemical Change
Part One:
Physical or Chemical Property? Fill in the chart using the vocabulary words or phrases provided.
Vocabulary words
Boiling point
Ability to rust
Melting point
Brittleness
elasticity
Flammability
Density
Transparency
Reactivity with
vinegar
ductility
Each word is used once. Define the word when done!
Chemical Property↓
Definition
• The ability to burn
• Reacts with oxygen to produce rust
Physical Property↓
Part Two:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Definition
• The property of letting light pass through something
Physical or Chemical Change? Indicate with a ‘P’ or a ‘C’ which type of change is taking place.
____________ glass breaking
____________ hammering wood together
____________ a rusting bicycle
____________ melting butter
____________ separate sand from gravel
____________ bleaching your hair
____________ frying an egg
____________ squeeze oranges for juice
____________ melting ice
10.
11.
12.
13.
14.
15.
16.
17.
18.
____________ mixing salt and water
____________ mixing oil and water
____________ water evaporating
____________ cutting grass
____________ burning leaves
____________ fireworks exploding
____________ cutting your hair
____________ crushing a can
____________ boiling water
WORKSHEET
#3
Dougherty Valley HS Chemistry
Classification of Matter WS
Directions: On a separate sheet of paper, design a classification scheme for the following. There
may be many ways to accomplish this. Find one that makes sense to you:
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
WORKSHEET
#4
Dougherty Valley HS Chemistry
Atomic Number and Mass Number
Directions: Complete the following chart and answer the questions below:
Element
Name
carbon
Atomic
Number
Number of
Protons
Number of
Neutrons
Number of
Electrons
Mass Number
12
8
8
hydrogen
1
6
hydrogen
14
2
nitrogen
14
1
92
2
146
cesium
82
11
12
47
tungsten
108
110
45
24
80
52
89
silver
152
107
76
114
Use the backside of this sheet to answer the following questions.
[1] How are the atomic number and the number of protons related to each other? Support.
[2] How do the number of protons, number of neutrons, and the mass number relate to each other?
Explain.
[3] What is the one thing that determines the identity of an atom (that is, whether it is an oxygen atom
or a carbon atom, etc.)? Support.
Dougherty Valley HS Chemistry
Atomic Structure Practice
[1]
Name:
Date:
Period:
WORKSHEET #5
The 3 particles of the atom are:
a. ______________________
b. ______________________
c. ______________________
Their respective charges are:
a. ______________________
b. ______________________
c. ______________________
[2] The number of protons in one atom of an element determines the atom’s ______________________, and the number
of electrons determines ______________________ of and element.
[3] The atomic number tells you the number of ______________________ in one atom of an element. It also tells you the
number of ______________________ in a neutral atom of that element. The atomic number gives the “identity “of an
element as well as its location on the Periodic Table. No two different elements will have the ______________________
atomic number.
[4] The ______________________ of an element is the average mass of an element’s naturally occurring atom, or
isotopes, taking into account the ______________________ of each isotope.
[5] The ______________________ of an element is the total number of protons and neutrons in
the______________________ of the atom.
[6] The mass number is used to calculate the number of ______________________ in one atom of an element. In order
to calculate the number of neutrons you must subtract the
______________________ from the ______________________.
[7]
[8]
[9]
Give the symbol and number of protons in one atom of:
Lithium __________________
Bromine __________________
Iron __________________
Copper __________________
Oxygen __________________
Mercury __________________
Krypton __________________
Helium __________________
Give the symbol and number of electrons in a neutral atom of:
Uranium __________________
Chlorine __________________
Boron __________________
Iodine __________________
Antimony __________________
Xenon __________________
Give the symbol and number of neutrons in one atom of:
(To get “mass number”, you must round the “atomic mass” to the nearest whole number)
Show your calculations.
Barium __________________
Bismuth __________________
Carbon __________________
Hydrogen __________________
Fluorine __________________
Magnesium __________________
Europium __________________
Mercury __________________
[10] Name the element which has the following numbers of particles:
a. 26 electrons, 29 neutrons, 26 protons _____________________
b. 53 protons, 74 neutrons _____________________
c. 2 electrons (neutral atoms) _____________________
d. 20 protons _____________________
e. 86 electrons, 125 neutrons, 82 protons (charged atom) _____________________
f. 0 neutrons _____________________
[11] If you know only the following information can you always determine what the element is? (Yes/No).
a. number of protons ___________
b. number of neutrons___________
c. number of electrons in a neutral atom___________
d. number of electrons___________
[12]
X = element symbol
A = mass number [# of protons (p) + # neutrons (n)]
Z = atomic number [# of protons]
N = # of neutrons
A-Z=N
A typical isotopic symbol takes this form:
ex. The isotopic symbol for Fluorine would be
Fill in the missing items in the table below.
Name
Symbol
Z
A
#p
#e
#n
Isotopic Symbol
#p
#e
#n
Isotopic Symbol
#e
#n
Isotopic Symbol
Na
17
Potassium
Fill in the missing items in the table below.
Name
Symbol
P
Z
A
Iron
53
Fill in the missing items in the table below.
Name
Silver
Symbol
Z
36
W
A
#p
ATOMIC WEIGHTS
STUDENT PRACTICE
Look at the atomic weights of a few different elements
on your periodic table. Do you notice that very few of the
elements have atomic weights that are close to being
nice whole numbers?
NOTE: The numbers in each of the following problems
have been made up. If we used actual percentages and
masses of isotopes then you could simply look up the
atomic weight of the element on the periodic table.
Do you know why this is? After all, for our purposes, the
mass of both the proton and the neutron are almost
exactly 1, and in chemistry we usually ignore the mass
of the electron because it is so very small.
1. Suppose that there were two isotopes of Sodium. 28%
of the naturally occurring sodium atoms had a mass of
22, and 72% atoms had a mass of 23. What would the
average atomic weight of sodium be?
Why then, if the mass of the atom comes mainly from
the protons and neutrons it contains, don’t the atomic
weights of the all come out to be nice whole numbers?
The reason is this; the atomic weights given on your
tables are “weighted averages” of the weights of the
different naturally occurring isotopes of the element.
Let’s look at an example.
Approximately 75% of the chlorine atoms found in nature
have a mass of 35. The other 25% have a mass of 37.
What should we report as the atomic weight for chlorine?
What we do is to take the “weighted average” of these
isotopes. We multiply 75% times 35 and then add that to
25% times 37...
2. Suppose that there were two natural isotopes of
Copper. 80% of the atoms had a mass of 63, and 20% of
the atoms had a mass of 65. What would that average
atomic weight of copper be?
[(.75)(35)] + [(.25)(37)]
= 26.25 + 9.25
= 35.5 amu
In cases where there are three known isotopes you
would simply multiply each mass number by the %
(expressed as a decimal) of the atoms with that mass
and then add the products together.
3. Suppose that a new element (E) were discovered that
existed as three natural isotopes. 25% of the atoms had
a mass of 278, 38% had a mass of 281, and the
remainder had a mass of 285. What would be listed as
the atomic weight of this element?