Warm Up
1.
2.
3.
4.
8-25-15
Convert 30 in to ft
Convert 19 g to kg
Convert 7.4 m to cm
Which is larger: 658 cm or 658 km?
Agenda
Turn in Lab Volume
Go over Safety Quiz
Notes Unit 1-3
Lab Density
Homework
Quiz Unit 1
Aug 28 - Online HW Unit 1
Sept 3 - Test Unit 1
Unit 1-3
How is Matter Classified?
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What does it mean to classify
information?
Why is it important to classify
information?
Pure Substances
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Pure substance
 One type of element or a single compound,
that has definite chemical and physical
properties
– Examples include copper, oxygen, and
carbon dioxide
– Elements, molecules or compounds
Pure Substances

Elements
 Pure substances that contain only one
type of atom (e.g. He, Li)
– Some elements are diatomic (they are never
found naturally by themselves. They have a
“buddy”)

H2, O2, N2, Cl2, Br2, I2, F2
Pure Substances

Molecules
 two or more atoms (usually the same
elements)
 Diatomic gasses (H2, O2, N2, Cl2, Br2, I2, F2)
– A molecule is the smallest unit of a substance
that keeps all the physical and chemical
properties of that substance
– It can consist of one atom or two or more atoms
bonded together
– Example: Helium versus Hydrogen
Pure Substances

Compounds
 A substance made up of atoms of two or
more different elements joined by
chemical bonds (e.g. CO2)
 All compounds are molecules
– Compounds can be made from their elements
and also broken down into their components
Pure Substances
Element
Compound or Molecule
Molecule
Mixture
Mixtures

Mixture: A combination of two or more
substances that are NOT chemically
combined
– Example: air is a mixture of nitrogen, oxygen,
argon, and carbon dioxide
– Example: pure water is NOT a mixture because
H is chemically bonded to O to form H2O
Mixtures

Homogeneous mixtures
 When pure substances are distributed
evenly throughout the mixture
– The different components of the mixture cannot
be identified by looking at it
– Examples: air, gasoline, syrup
Mixtures

Heterogeneous mixtures
 When pure substances are NOT evenly
distributed throughout the mixture
– You can see the different
components in the mixture
– Example: ice tea, cereal
Properties of Matter

Chemical Properties: A property of
matter that let it react with another
chemical
– Chemical properties can only be identified by
trying to cause a chemical change
Properties of Matter

Physical Property: A property that can
be determined without changing the
nature of the substance
– Example: sugar’s physical properties would
include that it is solid, white
– More examples:
State of matter
 Melting points
 Boiling point
 Mass and volume
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Properties of Matter
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Density = mass/volume
g/cm3
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The density of an object is the
same no matter its volume
-Density is also a physical property of
matter that can be used to identify
substances (stuff per space)
Density Example Problems
1. What is the density of an object that weights
2200g and has a volume of 100cm3?
2. Gold’s density is 19.3g/cm3 If a gold bar has
mass of 150g what is its volume?
3. Find the density of this cube.
Mass = 30g
Density Lab
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Follow the lab procedure to find the volume
of pennies and metal cylinders
Find the unknown materials used to make
the cubes by finding its density
Lab due before class is over
Unit 1 Density WS due at the end of
next class
Mixture Vs. Compound
Review
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A mixture is composed
of two or more
substances that are
physically mixed
Properties of mixtures
reflect the substances it
contains
Mixtures can have
varying proportions
Mixtures can be
separated based on the
physical properties of
the substances
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A compound is
composed of two or
more elements
chemically joined
Properties of
compounds have
different properties
than the elements that
make them up
Compounds have
definite proportions
Compounds can only be
separated into its
components through
chemical change