Matter
Properties
http://z.about.com/d/chemistry/1/0/x/c/transitionmetalsolns.jpg
So What is Matter?
• Anything that occupies space and has
mass
What isn’t matter?
• Energy
• Ideas, gravity, shadows…
Properties
• Physical Property - any property that can be
observed without transforming the substance
into another substance
mass, color, freezing point
• Chemical Property - any property that cannot
be studied without transforming the
substance into a different substance
iron rusts, paper burns
Properties
• Intrinsic property– does not depend on the
amount of material you have
color, solubility, viscosity, malleability, boiling
point
• Extrinsic property – depends on the amount
of matter
mass, volume, length
What is density?
Density
• Property derived from two measurements,
mass and volume
• Density = Mass/Volume
• Will have a unit that contains both mass and
volume such as g/cm3, lb/gal, kg/L
• Does not depend on the size of the sample
Density
• What is the density of a sample of metal that
has a mass of 34.58 g and when placed in 15.0
mL of water causes the level to rise to 22.4
mL?
22.4 mL - 15.0 mL = 7.4 mL
M 34.58 g
D=
=
= 4.7 g/mL
V
7.4 mL
CHM 1010
PGCC
Barbara A. Gage
Changes
• Physical Change - change that does not
transform the substance into another
substance
melting, subliming, dissolving
Physical Changes
• What were the physical changes that you
encountered in the activities on Day 2?
Splint broken into pieces
NaCl dissolved in water
Sand and salt mixed
Alum heated and cooled
Changes
• Chemical Change - change that transforms one
substance into another substance
burning,
oxidation of metal
precipitation of solid
Chemical Changes
• What were the chemical changes you
encountered on Day 2?
Burning of ethanol
Heating CuCO3
Reaction of cobalt chloride and sodium
phosphate
Burning splint Ethanol and KMnO4
Chemical Change
From Silberberg, Principles of Chemistry, 2007
CHM 1010
PGCC
Barbara A. Gage
Distinguishing Between Physical and Chemical Changes
PROBLEM: Decide whether each of the following process is primarily a
physical or a chemical change, and explain briefly:
(a) Frost forms as the temperature drops on a humid winter night.
(b) A cornstalk grows from a seed that is watered and fertilized.
(c) Dynamite explodes to form a mixture of gases.
(d) Perspiration evaporates when you relax after jogging.
(e) A silver fork tarnishes slowly in air.
SOLUTION:
(a) physical change
(b) chemical change
(d) physical change
(c) chemical change
(e) chemical change