2.1 Properties of Matter
• Identify properties of matter as extensive
or intensive.
• Define physical property and list several
common physical properties of
substances.
• Differentiate among three states of matter.
• Describe a physical change.
Properties of Matter
Bamboo has properties
that make it a good choice
for use in chopsticks. It
has no noticeable odor or
taste. It is hard, yet easy
to split, and it is heat
resistant. You will learn
how properties can be
used to classify and
identify matter.
Properties of Matter
• Properties: used to identify substances
• Extensive: depends on the amount of
matter
• Intensive: depends on the nature of
matter (NOT the amount)
Properties of Matter
Physical Property
observed or measured without changing the
substance’s composition
ex.: mass, color, density, melting point,
boiling point, state, etc.
States of Matter
There are three states of matter:
solid: definite shape and definite volume,
can not be compressed easily
liquid: no definite shape but definite
volume, also difficult to compress
gas: no definite shape or volume, easily
compressed
(vapor : gaseous state of a substance that
is normally a solid or liquid)
Physical Changes
• do not involve a change in the identity of
the substance
• Physical changes can be reversible
• or irreversible
Physical Changes
As gallium melts in a
person’s hand, the shape
of the sample changes,
but the composition of the
material does not
change.
2.1 Section Quiz.
– 1.
Which of the following would be
described as an extensive property of
matter?
• temperature
• color
• mass
• hardness
– 2.
Which properties can be observed
without changing the composition of a
substance?
•
•
•
•
all properties of a substance
intensive properties
chemical properties
physical properties
– 3.
Match the states of matter with the
following descriptions:
(1) takes the volume and shape of its container
(2) has a definite shape and volume
(3) has a definite volume but an indefinite shape
• (1) liquid, (2) solid and (3) gas
• (1) gas, (2) solid, and (3) liquid
• (1) gas, (2) liquid, and (3) solid
2.2 Mixtures
• Categorize a sample of matter as a
substance or a mixture.
• Distinguish between homogeneous and
heterogeneous samples of matter.
• Describe two ways that components of
mixtures can be separated.
Mixtures
• mixtures: physical blend of two or more
components with each component keeping
its own properties
• the composition of a mixture is not definite
throughout like a substance
Types of Mixtures
Heterogeneous mixtures: composition is
not uniform throughout
Homogeneous mixtures: composition is
uniform throughout (often called solutions)
phase: part of a sample with uniform
composition and properties
Separating Mixtures
• differences in physical properties can be
used to separate mixtures
• filtration: separates solids from liquids in a
heterogeneous mixture
• distillation: separates a liquid from solids
and liquids in a homogeneous mixture
Solve
2.2 Section Quiz.
– 1.
Which of the following phrases
describes a mixture?
• composition varies
• composition may vary
• components cannot be separated
2.2 Section Quiz.
– 2.
Which of the following is a
homogeneous mixture?
• vinegar
• iron filings in sand
• chicken noodle soup
• muddy water
2.2 Section Quiz.
– 3.
Which technique is used to
separate homogeneous mixtures?
• filtration
• distillation
• magnetism
• dissolving
2.3 Elements and Compounds
• Explain the difference between an element
and a compound.
• Distinguish between a substance and a
mixture.
• Identify the chemical symbols of elements,
and name elements, given their symbols.
Elements and Compounds
• element: simplest form of matter that has
a unique set of properties
• compound: substance made of two or
more different elements chemically
bonded (not mixed) in a fixed proportion
• properties of compounds: are different
from properties of the elements that make
them up
ex.: H20
Substances
• If the composition of a material is fixed, the
material is a substance.
• If the composition of a material may vary,
the material is a mixture.
Chemical Change
• produces matter with a different
composition than the original matter
– one or more substances react to form new
substance(s)
Symbols and Formulas
• chemical symbol: represents an element
using a capital letter and sometimes a
second lower case letter
• symbols come from the element names
which are usually English but can be Latin
or from some other source
Symbols and Formulas
• subscripts: indicate the number of atoms
of an element in any compound
• chemical formula: represents the number
and type of elements in a compound
• compounds have a fixed composition so
there formula will always be the same
2.3 Section Quiz
– 1.
Passing an electric current
through a certain substance produces
oxygen and sulfur. This substance
cannot be a(n)
• compound.
• mixture.
• element.
• solution.
2.3 Section Quiz
– 2.
Which of the following is a
mixture?
• sodium chloride
• carbon dioxide
• sucrose
• air
2.3 Section Quiz.
– 3.
The symbol for the element
potassium is
• K.
• Po.
• P.
• Pt.
2.4 Chemical Reactions
• Describe what happens during a chemical
change.
• Identify four possible clues that a chemical
change has taken place.
• Apply the law of conservation of mass to
chemical reactions.
Chemical Reactions
• chemical property: ability of a substance
to undergo a specific chemical change
• chemical changes are also referred to as
chemical reactions
• reactants form products
Indications of Chemical Change
• all of these indicate a possible chemical change
but may not mean one has actually occurred
• energy transfer
– observed as heat absorbed or given off and/or light
being given off
• color change
• gas production
– observed as bubbles being given off
• formation of a precipitate
– observed as a solid settling out of a liquid
Law of Conservation of Mass
• Mass is neither created nor destroyed.
• In a chemical reaction,
the mass of the reactants
equals
the mass of the products