1.3: Phases of Matter
and the Kinetic Molecular Theory (KMT)
8/5/16
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Phases of Matter & the KMT
A. What is Matter?
• matter = anything that has mass and takes up space (has volume).
• YES = water, charcoal, glass, people, etc.
• NO = light, sound, electricity
• chemistry = the study of matter and how it changes.
B. The KMT and Phases
• kinetic molecular theory = explains the properties of matter
1. All matter is made of atoms and molecules that act like
tiny particles.
2. These tiny particles are always in motion. The higher the
temperature, the faster the particles move.
3. At the same temperature, more massive particles move
slower than less massive particles.
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Phases of Matter & the KMT—con’t.
• There are three main phases (states) of matter:
Phase
Structure
Distance btwn. Particles
Movement
rigid, fixed
very small
vibration
Solid
Liquid shape of container
small
fluid movement
shape of container
large
very fast, random
Gas
high-temp. phase in which atoms lose their electrons
Plasma
(ex: fluorescent bulb)
(Note: Plasmas don’t behave normally in chemical reactions,
so we will not spend too much time on them.)
Microscopic Views of Each Phase
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Phases of Matter & the KMT—con’t.
Solid
Liquid
Gas
Microscopic Views of Each Phase
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Phases of Matter & the KMT—con’t.
C. Phase Changes
• energy = the ability to change or move matter. Required to
change the phases of matter from one to another.
• there are six different phase changes:
1. melting = change in phase from solid to liquid
(ex: ice turning into water)
2. evaporation = liquid to gas
(ex: puddles disappearing as
temps. heat up)
3. sublimation = solid directly to gas (no liquid)
(ex: ice cubes shrinking over time, dry ice)
• the three phase changes listed above are endothermic because
energy (in the form of heat) is absorbed into the substance
during the change.
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Phases of Matter & the KMT—con’t.
• the other three phase changes:
4. freezing = liquid to solid (ex: hot candle
wax cooling and solidifying)
5. condensation = gas to liquid
(ex: a cold drink “sweating”)
6. deposition = gas directly to solid (no liquid)
(ex: frost forming on cold surface,
like early-morning grass)
• the three phase changes listed above are exothermic because
energy (in the form of heat) is released from the substance
during the change.
• important to remember: just because energy is absorbed/released
doesn’t mean the temperature of a substance changes during the
phase change. In fact, it stays the same! (more on this later)
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Phases of Matter Graphic Organizer Directions
•
Choose 3 main colors:
• one color for the matter you will draw in the beakers
• another color for the exothermic phase change arrows
• and a last color for the endothermic phase change arrows
•
Using about 30 ¼-inch circles, draw a picture representing the arrangement of
particles of matter of a solid the beaker marked solid.
•
Using about 30 ¼-inch circles, draw a picture representing the arrangement of
particles of matter of a liquid in the beaker marked liquid.
•
Using about 20 ¼-inch circles, draw a picture representing the arrangement of
particles of matter of a gas in the beaker marked gas.
•
Label the arrows with the correct phase changes that take place between the two
phases represented in each pair of beakers. Be careful—use the correct terms!
•
Color all the exothermic phase change arrows the same color, including the key
arrow under the title.
•
Color all the endothermic phase change arrows the same color, including the key
arrow under the title (must be a different color from the exothermic arrows).
•
Write a description of each phase on the lines closest to the beaker you are
describing. Be brief, but detailed.
•
Write your name, date, and period on the bottom of the page in the area provided.
•
Turn it in!