Download Chapter 2 Matter and Change

Chapter 3
“Matter and
Change”
Matter
 Matter is anything that has mass,
and takes up space
Copper Phases - Solid
Copper Phases - Liquid
Copper Phases – Vapor (gas)
Solid
Liquid
Gas
Shape
Volume
Spacing
definite
indefinite
definite
definite
indefinite
compact
Loosely
Spread
Spaced
Out
indefinite
4th state: Plasma - formed at high
temperatures; ionized phase of matter as
found in the sun
Properties are…

Physical Properties- a property that can
be observed and measured without
changing the material’s composition.
Extensive Properties
Intensive Properties
Depend on the amount
Length
Shape
Weight
Same no mater how much
you have
Density
Hardness
Odor
Taste
Solubility/Dissolving
Melting point
Boiling point
Condense
Freeze
Evaporate
Melt
Solid
Liquid
Gas


Chemical Properties- a property that can
only be observed by changing the
composition of the material.
Examples- ability to burn, decompose,
ferment, react with, etc.
Physical vs. Chemical Change

Physical change will change the
appearance, without changing the
composition of the material.



Boil, melt, freeze, cut, bend, split, crack
Can be reversible, or just changes shape
Chemical change - a change where a new
substance is produced and is not reversible

Rust (iron oxidation), burn, decompose, ferment,
explode, tarnish (silver oxidation)
Quiz Time

Which of the following are physical changes.





A. making caramel from sugar
B. Carving a wooden figurine
C. Freezing mercury
D. Dissolving salt in water
Classify each of the following as a substance or a
mixture.




A. silver
B. alphabet soup
C. Textbook
D. Table salt (sodium chloride)
Evidence of a chemical
reaction






Product is different than reactants
Ex:
Color change
Temperature change
Gas Produced (bubbles)
Light produced
Law of Conservation of Mass



“Mass is neither created or destroyed”
Mass of the reactants (the stuff being put into
the reaction) must equal the mass of the
products (the stuff made once the reaction
has taken place).
Reactants
Products
Mass = Mass
Law of conservation of mass

Example: A 5 g sample of A reacts with a B to
form 25 g of AB. What was the mass of B
that reacted?
Law of Conservation

8 g of hydrogen react completely with 64 g of
oxygen, how much water is produced?
Elements, Mixtures, and
Compounds

EQ: How is matter separated?
Element:

Simplest form of matter that has a unique set
of properties
Compound:

A substance that contains two or more
elements chemically combined or more
elements chemically combined in a fixed
proportion.
Mixture:

A physical blend of two or more substances.
Homogeneous Mixture:

A mixture in which the composition is uniform
throughout. Another name for a
homogeneous mixture is solution.
Heterogeneous Mixture:

A mixture in which the composition in not
uniform throughout.
Separating Mixtures

Differences in physical properties can be
used to separate mixtures. In our chemistry
class we will examine filtration, distillation
and evaporation.
Physical Sorting

Separates Large solids using your hands
Magnetic

Separates magnetic metals like iron using a
magnet
Filtration:

The process of separating a solid from a liquid
using a filter.
Paper Chromatography
Pigments are separated from liquid using
paper.
Distillation:

Liquids can be separated based on their
differences in boiling point
Crystalizaion:

Separates solids from liquids using
evaporation.
Breaking down compounds:

Involves a chemical change. Heating is one
of the processes used to break down
compounds into simpler substances.
Mixtures are a physical blend of at
least two substances; have variable
composition. They can be either:
1) Heterogeneous – the mixture is not
uniform in composition

•
Chocolate chip cookie, gravel, soil.
2) Homogeneous - same composition
throughout; called “solutions”
•

Kool-aid, air, salt water
Every part keeps it’s own properties.
Separating Mixtures
Some can be separated easily by
physical means: rocks and marbles,
iron filings and sulfur (use magnet)
 Filtration - separates a solid from the
liquid in a heterogeneous mixture (by
size)

Separation of a Mixture
Distillation: takes advantage
of different boiling points.
Compound or Mixture?
Compound
Mixture
Made of one kind
of material
Made of more than
one kind of material
Made by a
chemical change
Made by a
physical change
Definite
composition
Variable
composition
Which is it?
Mixture
Element
Compound
Elements vs. Compounds
Compounds can be broken down
into simpler substances by chemical
means, but elements cannot.
 A “chemical change” is a change that
produces matter with a different
composition than the original matter.

Classification of Matter
Symbols & Formulas

An element’s first letter always capitalized; if
there is a second letter, it is written
lowercase: B, Ba, C, Ca, H, He
Chemical Changes

The ability of a substance to undergo a
specific chemical change is called a
chemical property.
•

iron plus oxygen forms rust, so the ability to
rust is a chemical property of iron
During a chemical change (also called
chemical reaction), the composition of
matter always changes.
Chemical Reactions are…
When one or more substances are
changed into new substances.
 Reactants- the stuff you start with
 Products- what you make
 The products will have NEW
PROPERTIES different from the
reactants you started with
 Arrow points from the reactants to the
new products

Recognizing Chemical Changes
1) Energy is absorbed or released (temperature
changes hotter or colder)
2) Color changes
3) Gas production (bubbling, fizzing, or odor
change; smoke)
4) formation of a precipitate - a solid that
separates from solution (won’t dissolve)
5) Irreversibility - not easily reversed
But, there are examples of these that are not
chemical – boiling water bubbles, etc.
Conservation of Mass
During any chemical reaction, the mass
of the products is always equal to the
mass of the reactants.
 All the mass can be accounted for:


Burning of wood results in products that
appear to have less mass as ashes; where
is the rest?
 Law
of conservation of mass
- Page 55
43.43 g Original mass = 43.43 g Final mass
reactants
=
product
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