Chapter 4: States of Matter

Section 1: Four States of Matter

Vocabulary States of matter Solid Liquid Gas Plasma

Vocabulary States of matter Solid Liquid Physical forms of matter 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 Melting Evaporation Change of a substance from one physical state to another Melting Solid changing to a liquid Evaporation Liquid changing to a gas

Vocabulary Boiling Condensation Sublimation 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? 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

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