Title: Feb 14­11:20 AM (1 of 58)
Introduction to Chemistry
What is chemistry?
Title: Feb 12­6:47 PM (2 of 58)
Title: Dec 3­11:24 AM (3 of 58)
Introduction to Chemistry
What is chemistry?
Definition:
The study of matter, its structure and properties, and how it changes
during chemical reactions.
Properties of Matter:
Characteristics of a material that allow you to identify it.
Title: Feb 12­6:47 PM (4 of 58)
Defining Matter
What is matter? Give me some examples of things you would call matter.
Can you give examples of things that are not matter?
Title: Feb 12­6:47 PM (5 of 58)
Defining Matter
Matter can be defined as anything that has both mass and volume.
Mass is similar to (but not the same as) weight*; volume simply means that matter takes up space.
*Another way to define mass is "resistance to change in motion".
This eliminates the problem of objects which don't have weight (for example, in space); they will still have mass, and still resist changing their motion in proportion to their mass.
Title: Feb 12­6:47 PM (6 of 58)
Classifying Matter
We can break all matter into two major categories
Title: Feb 12­6:47 PM (7 of 58)
1)
Pure Substances
2)
Mixtures
Classifying Matter
Pure Substances include Elements and compounds.
These materials have a uniform and fixed composition. Uniform ­ all parts of the substance are the same
Fixed ­ the ratio of elements within the material is not variable
Title: Feb 12­6:47 PM (8 of 58)
Particles of Matter
We say that all matter is composed of "small particles".
What do we call the smallest particles of matter?
We define atoms as the simplest particles of matter which
retain their properties.
The last part is important...atoms are not the absolute smallest particles of matter, but a single atom still has all the same properties as the material it's made of...
if it is broken down any further, those properties are lost.
Title: Feb 12­6:47 PM (9 of 58)
Title: Dec 4­8:10 AM (10 of 58)
Atoms
What do we call a material composed entirely of a single type of atom?
Examples of elements:
Title: Feb 12­6:47 PM (11 of 58)
Classifying Matter
Elements ­ Substances composed entirely of a single type of atom
All of the elements are listed in the Periodic Table. Examples: oxygen, iron, helium, neon, sodium
Title: Feb 12­6:47 PM (12 of 58)
Periodic Table
All of the elements are listed in the periodic table.
There are about 120 known elements, although many of these are very uncommon, and some do not occur naturally.
There is a great variety of properties among the elements.
Most are solid at room temperature, some are a gas at room temperature, and only two (Bromine and Mercury) are liquid at room temperature.
The elements can be divided into groups based on their properties.
Title: Feb 12­6:47 PM (13 of 58)
1
Periodic Table of the Elements
H
Hydrogen
3
Lithium
11
Each element on the periodic table has a name and a symbol.
Be
Beryllium
12
Na
Mg
Sodium
Magnesium
19
K
Potassium
37
20
Ca
Calcium
38
Rb
Sr
Rubidium
Strontium
55
56
Cs
Cesium
87
Fr
Francium
He
Helium
4
Li
2
Ba
Barium
88
The symbol can be a single capital letter, or a capital and lowercase letter.
21
22
23
24
25
26
27
28
29
30
5
7
6
8
9
C
N
O
F
Ne
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
13
14
Al
Aluminium
31
15
Si
Silicon
32
16
17
P
S
Cl
Ar
Sulfur
Chlorine
Argon
33
34
35
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Scandium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
41
42
43
Y
Yttrium
57
40
Zr
Zirconium
72
Nb
Mo
Tc
Niobium
Molybdenum
Technetium
73
74
La
Hf
Ta
Lanthanum
Hafnium
Tantalum
89
Ra
Ac
Radium
104
105
75
45
Ru
Rh
Rhodium
76
77
Ir
Pt
Iridium
Platinum
106
107
Actinium Rutherfordium
Dubnium
Seaborgium
Bohrium
Hassium
58
60
62
63
Cerium Praseodymium
90
91
61
Pm
109
Mt
Meitnerium
64
79
49
Cd
Cadmium
80
50
51
52
Sb
Te
I
Xe
Tellurium
Iodine
Xenon
81
82
Au
Hg
Tl
Gold
Mercury
Thallium
83
84
Pb
Bi
Lead
Bismuth
Polonium
65
66
67
68
69
70
Tm
Yb
Europium
Gadolinium
Terbium
Dysprosium
Holmium
Erbium
Thulium
Ytterbium
93
94
Np
Pu
Thorium
Protactinium
Uranium
Neptunium
Plutonium
95
96
Am Cm
Americium
Curium
97
98
99
100
101
102
71
Lu
Lutetium
103
Bk
Cf
Es
Fm
Md
No
Lr
Berkelium
Californium
Einsteinium
Fermium
Mendelevium
Nobelium
Lawrencium
86
At
Rn
Astatine
Radon
The symbols are usually related to the element's name, but not always.
Er
U
85
Po
Ho
92
54
Antimony
Dy
Pa
53
Tin
Tb
Th
Krypton
Sn
Gd
Samarium
Kr
Bromine
In
Eu
Promethium
36
Br
Indium
Sm
Neodymium
Title: Periodic table (14 of 58)
78
Os
Hs
Nd
Silver
Osmium
Bh
Pr
Ag
Re
108
48
Pd
Rhenium
W
47
Palladium
Tungsten
Sg
59
46
Ruthenium
Db
Ce
Rf
44
18
Phosphorus
Sc
39
10
B
Layout of the Periodic Table
Why is the table arranged the way it is?
Why is there that separate group down at the bottom?
Look at the gap between 56­71 and 88­103. The separate group, called the Rare Earth Metals, fits in between these elements. They are separated out from the others so that the table fits easily on a page! Otherwise, the table would be VERY long and thin...like this...
Title: Feb 12­6:47 PM (15 of 58)
Classifying Matter
Compounds ­ Substances composed of two or more types of atoms,
in a fixed ratio.
A compound formula shows the rationin which the
elements of a compound are fixed.
Examples: H2O (two hydrogen for every one oxygen)
C6H12O6 (6 carbon; 12 hydrogen; 6 oxygen)
Fe(NO3)2
Title: Feb 12­6:47 PM (16 of 58)
(1 iron; 2 nitrogen; 6 oxygen)
Title: Dec 4­10:55 AM (17 of 58)
Compounds
When two or more elements combine in a chemical reaction, they form a compound.
The atoms of each element join together, combining in a fixed ratio. Two elements may combine in more than one ratio, but the resulting compounds will be different, and will have different properties.
There are many more compounds in the world than elements:
Title: Feb 12­6:47 PM (18 of 58)
Compounds
Why do you think there can be so many more compounds than elements?
Think of this: Why are there more words than there are letters?
Title: Feb 12­6:47 PM (19 of 58)
Pure Substances
Atoms and compounds are called pure substances, because they are composed entirely of the same type of atoms, or of atoms combined in a fixed ratio.
In other words, all samples of a pure substance will be the same.
What would the particles look like in an element?
Title: Feb 12­6:47 PM (20 of 58)
What would the particles look like in an compound?
Mixtures
A mixture is two or more elements or compounds
There are even more mixtures than there are compounds. Not all elements will combine in a chemical reaction to form a compound, but any two (or more) elements or compounds can be tossed together to make a mixture.
What are some examples of mixtures?
Title: Feb 12­6:47 PM (21 of 58)
Mixtures
Mixtures do not have a fixed composition. They may be classified as either solutions or heterogeneous mixtures.
Solutions Composition is uniform, but variable. All the particles are spread out evenly, and all parts of the solution will appear the same. Solutions will still usually be transparent.* *Solutions may have color, but you can still see that light passes through them.
Heterogeneous mixtures ­ comosition is both variable and not uniform; there are at least two "phases" in the mixture; in other words, there are visible differences in different parts of the mixture.
Title: Feb 12­6:47 PM (22 of 58)
Mixtures
Classify the examples as solutions or heterogeneous mixtures:
Title: Feb 12­6:47 PM (23 of 58)
Drawing Mixtures
Remember what the particles in elements and compounds looked like?
What would the particles in a mixture look like?
Title: Feb 12­6:47 PM (24 of 58)
Homework: Pure Substances and Mixtures
Matter
Title: Feb 12­6:47 PM (25 of 58)
Review Homework
Read the Introduction to Chapter 5, and Section 5.1 (pages 170­174 in your text.)
Complete Questions #1­5 on page 175
Title: Feb 12­6:47 PM (26 of 58)
Review Homework
1.
Classify each of the following as a pure substance or
a mixture. Explain your choices.
(a)
Soapy water
(b)
Hydrogen gas
(c)
Sodium chloride
Title: Feb 12­6:47 PM (27 of 58)
Review Homework
2.
Classify each of the following as an element or a compound.
Explain your choices.
(a)
Hydrogen
(b)
Potassium carbonate
(c)
Water
(d)
Mg
Title: Feb 12­6:47 PM (28 of 58)
Review Homework
3.
Draw sketches to represent 10 particles of the following:
(a)
Element
(b)
Compound
(c)
Mixture
*These were already done during class notes
Title: Feb 12­6:47 PM (29 of 58)
Review Homework
4.
Classify each of the following as a physical property or
a chemical property. Explain your choices.
(a)
Gasoline is a clear, pink solution
(b)
Gasoline burns in air
(c)
Water boils at 100 C
(d)
Electric current can split water into
hydrogen and oxygen gases.
Title: Feb 12­6:47 PM (30 of 58)
Review Homework
5.
When aluminum metal is addes to hydrobromic acid, hydrogen gas and an aluminum bromide solution are formed. (a)
What kind of change has occurred? Explain.
(b)
Which substances are the reactants, and which
are the products?
Title: Feb 12­6:47 PM (31 of 58)
Question 6 from page 175
6.
In your own words, describe the chemical tests that can be
used to identify the following gases:
(a)
Hydrogen
(b)
Oxygen
(d)
Water vapor
(c)
Carbon dioxide (demo)
Title: Feb 12­6:47 PM (32 of 58)
Title: Dec 4­11:46 AM (33 of 58)
Properties of Matter
What is meant by a property of a substance?
What are some examples of properties of matter?
Title: Feb 12­6:47 PM (34 of 58)
Properties of Matter
Two types of properties:
Physical
Title: Feb 12­6:47 PM (35 of 58)
Chemical
States of Matter
What are the three states of matter?
Describe the properties you could use to identify each state.
Solid:
fixed shape and volume (solids maintain their shape, and are
non­compressible
Liquid: variable shape, but fixed volume (liquids take the shape of their
container, from the bottom up, but are still non­compressible
Gas:
variable shape and volume (gases take the shape of their container,
and they are compressible...they expand to fill their container, but
can be squeezed into smaller volumes when pressure is applied)
Title: Feb 12­6:47 PM (36 of 58)
Changes of State
Two useful properties of a material are its melting and boiling points. These are the temperatures at which the material changes state, going from a solid to a liquid (melting), or from a liquid to a gas (boiling...slower transition from liquid to a gas is called vaporization or evaporation.)
Title: Feb 12­6:47 PM (37 of 58)
Changes of State
These changes can also happen in reverse:
A change from a gas to a liquid is called condensation
A change from a solid to a liquid is called solidification or freezing
It is also possible for a material to change from a solid to a gas, or gas to solid, directly, without ever becoming a liquid in between. This is called sublimation.
Can you think of some examples of this happening?
Title: Feb 12­6:47 PM (38 of 58)
Metals and Nonmetals
Two major groups of elements are the metals and the nonmetals .
Look at the examples below. Which ones are metals? Nonmetals?
How can you tell?
Title: Feb 12­6:47 PM (39 of 58)
1
Periodic Table of the Elements
H
Hydrogen
3
Lithium
11
Most of the elements are metals. They are listed 5
B
on the left side of the table. Nonmetals are on the right side.
13
The far right are a special group called the inert Al
gases, or noble gases.
Be
Beryllium
Mg
Sodium
Magnesium
K
Potassium
37
20
Ca
Calcium
38
Rb
Sr
Rubidium
Strontium
55
56
Cs
Cesium
87
Fr
Francium
Boron
12
Na
19
He
Helium
4
Li
2
Ba
Barium
88
Aluminium
21
22
23
24
25
26
27
28
29
30
31
7
6
8
9
N
O
F
Ne
Carbon
Nitrogen
Oxygen
Fluorine
Neon
14
15
Si
Silicon
32
16
17
P
S
Cl
Ar
Sulfur
Chlorine
Argon
33
34
35
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Scandium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
41
42
43
Y
Yttrium
57
40
Zr
Zirconium
72
Nb
Mo
Tc
Niobium
Molybdenum
Technetium
73
74
La
Hf
Ta
Lanthanum
Hafnium
Tantalum
89
Ra
Ac
Radium
104
105
75
45
Ru
Rh
Rhodium
76
77
Ir
Pt
Iridium
Platinum
106
107
Actinium Rutherfordium
Dubnium
Seaborgium
Bohrium
Hassium
58
60
62
63
Cerium Praseodymium
90
91
61
Pm
109
Mt
Meitnerium
64
79
49
Cd
Cadmium
80
50
51
52
Sb
Te
I
Xe
Tellurium
Iodine
Xenon
81
82
Au
Hg
Tl
Gold
Mercury
Thallium
83
84
Pb
Bi
Lead
Bismuth
Polonium
65
66
67
68
69
70
Tm
Yb
Europium
Gadolinium
Terbium
Dysprosium
Holmium
Erbium
Thulium
Ytterbium
93
94
Np
Pu
Thorium
Protactinium
Uranium
Neptunium
Plutonium
95
96
Am Cm
Americium
Curium
86
At
Rn
Astatine
Radon
The noble gases are special nonmetals that are very unreactive...in other words, they almost never react with other elements.
Er
U
85
Po
Ho
92
54
Antimony
Dy
Pa
53
Tin
Tb
Th
Krypton
Sn
Gd
Samarium
Kr
Bromine
In
Eu
Promethium
36
Br
Indium
Sm
Neodymium
Title: Periodic table (40 of 58)
78
Os
Hs
Nd
Silver
Osmium
Bh
Pr
Ag
Re
108
48
Pd
Rhenium
W
47
Palladium
Tungsten
Sg
59
46
Ruthenium
Db
Ce
Rf
44
18
Phosphorus
Sc
39
10
C
97
98
99
100
101
102
71
Lu
Lutetium
103
Bk
Cf
Es
Fm
Md
No
Lr
Berkelium
Californium
Einsteinium
Fermium
Mendelevium
Nobelium
Lawrencium
Atomic Structure
What do you already know about the structure of atoms? (Brainstorm)
���������������
Title: Feb 12­6:47 PM (41 of 58)
Parts of an Atom
There are two main areas in an atom.
The center of the atom, where almost all of the mass is located, is the nucleus .
The nucleus is surrounded by an electron cloud .
Nucleus
Electron cloud
Title: Feb 12­6:47 PM (42 of 58)
Parts of an Atom
We said that, even though an atom is the smallest particle which keeps its properties, it is not the smallest particle of matter possible. Atoms are made up of three smaller particles. What are they?
Title: Feb 12­6:47 PM (43 of 58)
Parts of an Atom
What do you already know about protons, neutrons, and electrons?
See if you can fill in the following chart:
Particle >
Location >
Electric
Charge >
Relative
Size (AMU) >
Title: Feb 12­6:47 PM (44 of 58)
Proton
Neutron
Electron
Atomic Structure
Every element is made up entirely of atoms with a specific number of protons, neutrons, and electrons. All of the atoms of any element will have the same structure.
We'll look in more detail at atomic structure later.
Title: Feb 12­6:47 PM (45 of 58)
Atomic Structure
Turn to the periodic table in the back of your book.
Every element is made up entirely of atoms with a specific number of protons, neutrons, and electrons. All of the atoms of any element will have the same structure...in other words, the same number of protons, neutrons*, and electrons.
*Actually, the number of neutrons can vary slightly even among atoms of the same element....we'll cover that shortly.
Title: Feb 12­6:47 PM (46 of 58)
Reading the Periodic Table
Symbol
Atomic number
17
Element name
Title: Feb 12­6:47 PM (47 of 58)
Cl
35.453
Chlorine
Relative atomic mass
Reading the Periodic Table
Atomic number
The number of protons in the nucleus. This number will not change
for any element. (If there is a different number of protons, it isn't
the same element anymore!)
Electrons
The number of electrons will be the same as the number of protons.
Why is this?
Title: Feb 12­6:47 PM (48 of 58)
Reading the Periodic Table
Relative Atomic Mass
The atomic mass is the average mass for an atom of the element listed.
Not all atoms of the same element have identical atomic mass.
Why?
What do we call atoms of the same element with different atomic mass?
Title: Feb 12­6:47 PM (49 of 58)
Title: Feb 18­2:35 PM (50 of 58)
Homework
Atomic Structure
Fill in atomic structures, similar to what we just did during class, for the
following elements:
Hydrogen
Nitrogen
Sodium
Beryllium
Chlorine
Calcium
Iron
Copper
Bromine
Argon
Oxygen
Helium
Title: Feb 12­6:47 PM (51 of 58)
Chemical Changes
Chemical changes are what happens to matter during a chemical reaction.
(In other words...they are what you see when observing a chemical property)
Chemical changes are different from physical changes in a couple of very important ways:
*During a chemical change, a new material is formed (for example, when you burn wood in a fireplace, you produce
smoke and ashes)
*Chemical changes are usually not reversible (you can't un­burn the piece of wood.
Title: Feb 12­6:47 PM (52 of 58)
Chemical Changes
There are five main signs you look for that tell you a chemical reaction has happened between two materials:
1)
There is a color change
2)
A solid has formed from mixing two liquids (this is
called a precipitate)
3)
Bubbles are formed, without adding heat
4)
There is a change in energy (heat is produced or absorbed,
light is given off)
5)
There is a change in smell (an odor given off)
Title: Feb 12­6:47 PM (53 of 58)
Chemical Reactions Demonstration
Create a chart like the one shown below to record your observations for each of the chemical reactions that are demonstrated:
Observations before reaction:
Observations during/after reaction:
Signs that a chemical reaction has ocurred:
Title: Feb 12­6:47 PM (54 of 58)
Chemical Reactions Demonstration
Reaction 1: Silver nitrate solution and Sodium chloride solution
Reaction 2: Iron and copper (II) sulfate solution
Reaction 3: Copper (II) nitrate solution and potassium iodide solution
Reaction 4: Hydrochloric acid and zinc metal (use a lit wooden splint to identify the gas)*
Reaction 5: Silver nitrate solution and Sodium iodide solution
Reaction 6: Magnesium metal and oxygen (combustion)*
Reaction 7: Iron (III) nitrate and potassium thiocyanate
Reaction 8: Silver nitrate and potassium dichromate
Reaction 9: Copper (II) chloride solution and Sodium hydroxide solution
Reaction 10:
Barium hydroxide and ammonium thiocyanate (solids)*
*What is the difference between an endothermic reaction and an exothermic reaction?
Title: Feb 12­6:47 PM (55 of 58)
Title: Feb 12­7:41 PM (56 of 58)
Title: Dec 2­7:27 PM (57 of 58)
Title: Dec 2­7:27 PM (58 of 58)