Download Chapter 17 - Seymour ISD

Section 1: Composition of Matter
 Substance—either an element or a compound
 When all the atoms in a substance are alike, the
substance is an element.
 A compound is a substance with two or more elements
combined in a fixed proportion.
 Two or more substances that can be easily separated by physical
means form a mixture.
 Heterogeneous mixture—mixture of different and easily distinguishable
materials
 Colloid—heterogeneous mixture with larger particles that never settle;
colloids scatter light in the Tyndall effect
 A heterogeneous mixture containing a liquid in which visible particles settle
is called a suspension.
 Homogeneous mixture—contains two or more gaseous, liquid, or solid
substances blended evenly; also called a solution
Section 2: Properties of Matter
 Physical property—
characteristics of a material
which can be observed
without changing the
identity of the substances in
the material; examples
include color, shape, size,
melting point, and boiling
point
 Appearance—physical
description of a
substance
 Behavior—how a
substance acts; for
example, magnetism,
viscosity, ductility
 Physical properties such
as size and magnetism
can be used to separate
mixtures.
 Physical change—change in a substance’s
size, shape, or state of matter
 Substance does not change identity when it
undergoes a physical change
 Distillation is a process for separating a mixture
by evaporating a liquid and condensing its
vapor.
 Chemical property—characteristics of a substance
indicating that it can change chemically; for example,
flammability or light sensitivity of a substance
 When one substance changes to another
substance, a chemical change has occurred.
 Some chemical changes are indicated by
temperature change, smell, or bubble
formation.
 Other chemical changes occur very slowly such
as the formation of rust.
 Chemical changes can be used to separate
substances such as metals from their ores.
 Weathering of Earth’s surface involves both
physical and chemical changes.
 Physical—big rocks split into smaller ones;
streams carry rock particles from one location
to another
 Chemical—Chemical changes can occur in rocks
when calcium carbonate in limestone changes
to calcium hydrogen carbonate due to acid rain.
Rock Cycle
 Law of Conservation of
Mass—Mass of all
substances present
before a chemical change
equals the mass of all
substances after the
change.
1. Which element makes up
greater than 50 percent of the
elements dissolved in seawater?
A Sodium
B Sulfur
C Magnesium
D Chlorine
2. Which element is found
dissolved in seawater about
twice as much as magnesium?
F Calcium
G Sodium
H Sulfur
J Potassium
3. Which of the following is a
compound?
A Ca
B MgS
C Cl2
D Na
Classify the following as a mixture or pure
substance, and atom, molecule, or compound.
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
L.