Post on 05-Jan-2016
Chapter 4: States of Matter
Section 1: Four States of Matter
Vocabulary
• States of matter• Solid• Liquid• Gas• Plasma
Vocabulary
• States of matter– Physical forms of matter
• Solid– State of matter in which the volume and
shape of a substance are fixed• Liquid– State of matter that has a definite volume but
not a definite shape
Vocabulary
• Gas– State of matter that does not have definite
volume or shape• Plasma– State of matter that starts as a gas and then
become ionized – Has an electric charge
Matter: Moving Particles
• All matter is made of particles• States of matter depends on the motion
of those particles• “particles” = atoms and molecule – Molecule is a group of atoms that function as
one unit
Matter: Moving Particles
• Matter is in constant motion– Regardless of the state of matter– Even solid particles are in motion
Solids
• Particles very close together• Strong attraction between the particles• Particles do move– But not fast enough to overcome the
attraction between them– Particles locked in place– Only vibrate
Liquids
• Particles move fast enough to overcome some of the attraction between
• Particles collide with and slide each other• Particles stay close together– That is why the volume is fixed, but not
shape
Gases
• Particles have little attraction between them– Move freely – Collide randomly
• Amount of open space between particles can change– that is why the volume of a gas changes
Plasma
• 99% of the universe is plasma• No fixed shape or volume• Can conduct electricity– Inside are charged particles• Atoms with a positive or negative electric charge
• Occurs naturally in lightning & fire• Artificial = fluorescent lights & plasma
balls
Section 2:
Vocabulary
• Changes of state• Melting• Evaporation• Boiling• Condensation• sublimation
Vocabulary
• Changes of State– Change of a substance from one physical
state to another• Melting– Solid changing to a liquid
• Evaporation– Liquid changing to a gas
Vocabulary
• Boiling– Change of a liquid to a vapor (or gas), throughout
all of the liquid• Condensation– Change from a gas to a liquid
• Sublimation– Direct change from a solid to a gas
Energy and Changes of State
• All changes of state are physical changes– The identity of the substance doesn’t
change– Ice = H2O– Water = H2O– Steam = H2O
Energy and Changes of State
• Particles move based upon state• Particles have different energy levels in
different states– Liquid state has more energy than solid– Gas state has more energy than liquid
Melting: Solid to Liquid
• As temperature increases, so does particle movement
• The temperature at which substance changes from solid to liquid is melting point
• Particles absorb energy to overcome some of their attraction to each other– Slide past each other
Freezing: Liquid to Solid
• For freezing to occur, the attraction between particles must overcome the motion
• Decrease in energy
Freezing point and Melting point are the same temperature
Evaporation
• Liquid to a gas• Happens at the surface• Boiling is similar: liquid to gas– Occurs throughout the substance
Evaporation
• Atmospheric pressure affects boiling– Higher elevation substance boils at lower
temperature• Less pressure, so particles can move easier
Condensation: Gas to Liquid
• Condensation and evaporation are opposite/reverse of each other
• Condensation point is temperature where a substance goes from gas to liquid– Condensation point and boiling point are the
same temperature
Condensation: Gas to Liquid
• Large numbers of particles clump together– Attraction overcomes their motion that has
been keeping them apart (gas state)– Energy has been removed• Temperature has decreased
Sublimation: Solid to Gas
• Direct change from solid to gas• Dry ice• Must have temperature change ( + )
Test Hint
• At what degrees Celsius does water boil at?– 100 ⁰C
• Since boiling occurs throughout the substance, does the volume of water affect its boiling temperature?– No !– It just takes longer to boil 10 L of water vs a 10
mL– Same is true for all substances
• Turn to page 114 –DRAW the picture at the bottom of the
page–Label as shown in textbook
• Turn to page 119–DRAW the picture at the bottom of the
page–Label as shown in textbook