Matter: Properties &
Changes
Chapter 2 notes
(2.1)
Physical Properties of Matter
can be observed or measured without
changing the composition of the sample
Examples: color, phase, melting or boiling
point, density, hardness, odor, taste
•
•
•
•
States of Matter
Solid (s) - definite volume and shape
Liquid (l) - definite volume, but not shape
Gas (g) - no definite volume or shape
Plasma - highly ionized gas
(s)
(l)
(g)
sToP & tHinK
• Which state or states of matter
take(s) the shape of its container?
• Which state or states of matter can
change in volume (without adding
or subtracting from the sample)?
Physical Changes
• Physical changes alter a substance without
changing its composition
sToP & tHinK
1. Which of the following are physical
properties?
•
•
•
•
liquid at room temperature
reacts with metals to form H2 gas
acids and bases combine to form water and a
‘salt’
boils at 145 degrees Celsius
(2.2)
Mixtures…
• Mixture - a combination of two or more
pure substances, in which each substance
retains its individual chemical properties
• Heterogeneous mixture - does not blend
smoothly, individual substances are distinct
• Homogeneous mixture - solution; has a
constant composition throughout
sToP & tHinK
• Heterogenous or Homogeneous?
(1)
(2)
Separating Mixtures
• Filtration - porous barrier separates solid
from liquid
• Distillation - liquids separated by
differences in boiling point
• Crystallization - forms pure solids from
dissolved substances
• Chromatography - separation based
on ability to travel or be drawn across a
material
filtration
distillation
crystallization
chromatography
sToP & tHinK
What separation technique is shown in the following pictures?
A
B
(2.3)
Elements & Compounds
• Elements - pure substances that
cannot be broken down into
simpler substances
– on the Periodic Table!
• Compounds - two or more
elements bonded together that
can be broken down
sToP & tHinK
1. In your own words, what is the difference
between an element and a compound?
2. Classify the following as being elements or
compounds
a)
b)
c)
d)
e)
Sodium
Sodium chloride
Oxygen
Carbon dioxide
Copper
(2.4)
Chemical Properties
• the ability of a substance to
undergo chemical change
• Examples: “reacts with
oxygen to form rust”, “forms
a deep blue solution when
in contact with ammonia”
Chemical Changes
• Chemical changes alter the composition so
that a new substance forms
• Evidence of chemical change: formation of
a gas or solid (precipitate), smoke, fire, an
odor, temperature change, color change
– Law of Conservation of Mass: composition
changes, but mass doesn’t
sToP & tHinK
• Substance A is a yellow liquid and
substance B is a blue liquid. The two
are mixed and form a green liquid
and a white solid.
– What evidence suggests a chemical
change occurred?
– What other things could you look for to
determine if there was a chemical
change?
sToP & tHinK
- which shows physical change and which
shows chemical change?
• link to change animation #1
• link to change animation #2