Matter and Change
Chapter 2
Properties of Matter
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Matter has many different properties
These properties can be used to classify and
identify various forms of matter
Properties used to describe matter can be
classified as extensive or intensive
Extensive & Intensive
Properties
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Extensive properties
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Depend on amount of matter present
Examples: ?
Intensive properties
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Depend on type of matter
Do not depend on amount of matter present
Examples: ?
Identifying Substances
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A substance is matter that has a uniform and
definite composition
Any given substance will have a unique set of
intensive properties
These properties can be used to identify or
separate the substance from other
substances.
Problem: How could you separate a mixture
of iron filings from sugar?
Physical Properties
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Can be observed or measured without changing the
identity of the substance
States of Matter:
Solids
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Solids
Definite shape
Definite volume
Particles fixed in
place
States of Matter:
Liquids
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Liquids
Definite volume
Indefinite Shape
Particles can move
past each other
States of Matter:
Gases
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Gases
Indefinite shape
Indefinite volume
Easily compressed
Particles very far
apart
Particles moving
rapidly
Vapors and Gases
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Gases are substances that are normally in a
gaseous state at room temperature
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Examples: O2, N2, He
Vapors are substances in a gaseous state
that are normally solid or liquid at room
temperature
H2O (l) + heat  H2O (g)
Physical Changes
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Changes to a substance that do not involve a
change in composition
Reversible or irreversible
Melting
Freezing
Stretching
Chopping
Grinding
2.2 Mixtures
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A physical blend of two or more substances
Types of mixtures
Homogeneous
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Composition is uniform
Consists of a single phase
Heterogeneous
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Composition is not uniform throughout
Have two or more phases
Phases of a Mixture
Some heterogeneous
mixtures have
homogeneous
regions called phases
Separating Mixtures
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Use different physical properties of
substances to separate components
Some techniques include….
Filtration
Chromatography
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Many types
Distillation
Distillation
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Liquids can be separated by boiling point
2.3 Elements & Compounds
 An
element is the simplest form of
matter that has a unique set of
properties.
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Contains only one type of atom
C, H, O, He, Ag, Na, K, etc.
Periodic Table contains all known
elements
Elements & Compounds
A
compound is a substance that
contains two or more elements
chemically bonded in a fixed
proportion.

Contains two or more different types of
atoms

H2O water
C 6H 6
Ca(OH)2
C 2 H 4 O2
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benzene
calcium hydroxide
acetic acid
Elements are the simplest form
of matter
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Elements cannot be broken down into simpler
substances
Compounds can
C6H12O6 → __ C + __ H2O
C6H12O6 → 6 C + 6 H2O
Properties of Compounds
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Usually quite different than the properties of
the elements making up the compound
Different compounds have different physical
and chemical properties
Stop and think…….
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In chemistry, what is a particle?
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Is a compound a mixture? Why or why not?
2.3
Classifying Matter
Symbols & Formulas
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Elements are represented by symbols
Compounds are represented by formulas
Interpreting chemical formulas
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Subscripts indicate the number of atoms
HNO3
Na2O
C12H22O11
Compounds have a constant
chemical composition
Mass of Elements in Samples
25.0
Mass Fe (g)
20.0
15.0
Compound A
Compound B
Linear (Compound A)
10.0
Linear (Compound B)
5.0
0.0
0.0
2.0
4.0
6.0
8.0
10.0
12.0
Mass O (g)
14.0
16.0
18.0
20.0
2.4 Chemical Reactions
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Chemical property
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Tendency to undergo a specific type of chemical
change
E.g. acids donate protons
HCl + NaOH → NaCl + H2O
Chemical changes
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Involve a change in chemical composition
Atoms are rearranged to form new substances
HCl + NaOH → NaCl + H2O
Chemical Reactions
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Common terms that suggest chemical
change
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Rot, ferment, corrode, rust, burn, decompose, etc.
Process of chemical change
Reactants → Products
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HCl + NaOH → NaCl + H2O
Fe + S → FeS
C3H8 + 5O2 → 3CO2 + 4H2O
Recognizing Chemical
Change: Evidence?
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Energy transfer
Color change
Formation of a gas
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HCl + NaHCO3 → NaCl + H2O + CO2 (g)
Formation of a precipitate
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An insoluble solid product
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CaCl2 (aq) + NaOH (aq) → Ca(OH)2(s) + NaCl (aq)
Law of Conservation of Mass
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During chemical reactions matter is neither
created or destroyed
Mass of reactants = mass of productions
50 g + 25 g → 65 g + 10 g
Beginning mass = ending mass