The Science of Chemistry
Before chemistry there was…..
Alchemy
Alchemy:
A medieval science and philosophy
aiming to achieve:
1. Transmutation of base metals (like lead)
into gold
Alchemy
2. Discovery of a universal cure for disease
Alchemy
3. Discovery of a way to prolong life
Has modern science achieved
these things?
Wealth for all?
Cure for disease?
Prolonged life?
Why is Gold valuable?
•
•
•
•
•
Rare
Pretty
Soft, easy to shape
Resists corrosion
Chemically unreactive
The science that studies the
structure,
composition,
and properties
of substances
and their transformations
(Webster)
What are the simplest substances?
• The ELEMENTS ( only about 90 occur
naturally, 114 discovered)
• Listed in the Periodical Table
• Basic building blocks for all other more
complex substances (compounds) found
in the universe
Abundance of common elements in
the Universe
• 60% Hydrogen
H
element #1
• 37% Helium
He
element #2
• 3%
elements # 3-90
Abundance of elements on Earth
(crust and atmosphere)
•
•
•
•
•
•
35% iron
30 % oxygen
15 % silicon
13% Magnesium
2.4% nickel
4.6% others
Origin of the Elements
Big Bang
• 15-20 billion years ago
• Matter and energy scatter, expand, and
cool
• Matter condenses to form galaxies,
Element Hydrogen forms
• Stars form in galaxies. In stars, H fuses to
form Helium and energy
• More fusion allows heavier elements to
form
We are all star dust……
Matter
Anything that has mass and takes up space
(volume)
What is NOT matter???
Classification of Matter
Matter
Can it be separated by physical means?
If yes….
Then you have a Mixture
Physical ways to separate a
mixture
• Filtering
(particle size)
• Distillation
(boiling point)
(dissolved solid)
Physical ways to separate a
mixture
• Chromatography
(attraction to paper)
Is the mixture uniform throughout?
• IF yes, it is HOMOGENEOUS
If no, then the mixture is
Heterogeneous
Homogeneous vs. Heterogeneous
mixtures
Matter
Can it be separated
by physical means?
YES
NO
Mixture
Substance
Is it uniform throughout?
YES
NO
Homogeneous
Gatorade
Bronze
Brass
Homogenized beverages
Heterogeneous
Dirt
Sea shells
Rocky road ice cream
Non-homogenized beverages
If matter can NOT be separated by
physical means….
It is a SUBSTANCE
If the substance can’t be broken down, it is
an ELEMENT
Elements are made of only one type of atom
Ex. Aluminum, carbon, oxygen
SUBSTANCE
If the substance CAN be broken down, it is a
COMPOUND, made of two or more
different kinds of atoms chemically bonded
together.
Ex. Water (2 Hydrogens and 1 oxygen)
Matter
Can it be separated
by physical means?
YES
NO
MIXTURE
SUBSTANCE
Is it uniform throughout?
Can it be broken down?
YES
NO
Homogeneous
Heterogeneous
Gatorade
Bronze
Brass
Homogenized beverages
Dirt
Sea shells
Rocky road ice cream
Non-homogenized beverages
Yes
NO
COMPOUND
ELEMENT
WATER H20
SALT NaCl
Aluminum
Graphite (Carbon)
ELEMENTS
can be….
• MONATOMIC :
single atoms
Al
• DIATOMIC : two of the same atom
bonded together in pairs
O2
• POLYATOMIC: three or more of the same
atom bonded together
O3
7 Diatomic Elements
Particles of Matter
Review
What is……
MATTER
SUBSTANCE
MIXTURE
ELEMENT
COMPOUND
HETEROGENEOUS VS. HOMOGENEOUS
CHEMISTRY: THE STUDY OF
MATTER
Did you know that……..
One of the most popular “foods” in the
United States is an entirely SYNTHETIC
(man-made) mixture.
Can you guess what it is?
SODA
The average person consumes
40 GALLONS (!)
of soda each year
Mixture:
carbonated water
sweetener, acids,
flavorings, caffeine
States of Matter
GAS
LIQUID
SOLID
Physical Properties of Matter
The properties of a substance that can be
demonstrated without changing the
composition of the substance
Size (length, volume)
Density
Mass
Color
Physical Properties
Melting Point
Ex. Ice (solid water) starts to melt to liquid
water at 0 degrees Celsius
Boiling Point
Ex. Water boils into steam at 100
degrees Celsius
Physical Properties
Malleability: can be pounded into a new
shape without breaking
Metals are malleable
Physical Properties
Iron is malleable
Fe
Physical Properties
Ductility
Can be pulled into long wires without
breaking
Metals are ductile
Physical Properties
Crystal Shape
Reflects the regular arrangement of atoms in
the solid
Physical Change
A change in the sample of matter that does
not result in a NEW substance:
Phase Changes
Changes in shape
Solid
liquid
gas
Chemical Properties of Matter
How matter behaves when it changes into a
NEW substance.
EX. Iron rusts
Milk sours
eggs rot
paper burns
silver tarnishes
sugar ferments
leaves turn
Chemical Change
Substance changes into a NEW substance.
This change is often an irreversible and
permanent change in composition
Burning
Tarnishing
Rusting
Oxidizing
Chemical Reaction
Chemical changes mean a chemical reaction has occurred
REACTANTS
old substances
Sodium + Chlorine
Na
+
CL
become
PRODUCTS
new substances
sodium chloride
(table salt)
NaCL
Test Review
• Know names and symbols of common
elements
Name
As
Ca
Mn
Cu
K
Symbol
Sodium
Iron
Tin
Gold
Lead
Test Review
Matter
Classify the following samples of
matter
Classify the following samples of
matter
Classify the following samples of
matter
Classify the following samples of
matter
Classify the following samples of
matter
Classify the following samples:
Classify the particles of matter
Identify the following changes as
Physical or Chemical
Identify the following changes as
Physical or Chemical
Identify the following changes as
Physical or Chemical
Identify the following changes as
Physical or Chemical
Identify the following changes as
Physical or Chemical
Fe
Identify the following changes as
Physical or Chemical
Identify the following changes as
Physical or Chemical
Periodic Table Review
1. Elements are arranged according
to______
2. Vertical columns are called________
3. Horizontal rows are called ________
4. There are ______ periods in the table
5. Most elements are classified as _____
6. Where are the transition metals?
7. What are the metalloids?
Periodic Table Review
1.
2.
3.
4.
5.
Describe 3 properties of metals
Describe 2 properties of non metals
Group 2 metals are called____________
Group 17 non metals are called _______
What two elements are liquid at room
temperature?
6. How can you tell if a compound contains
a transition metal?