Chapter 3 States of Matter

Section 3.1 Solids, Liquids, and Gases

Describing the States of Matter Materials can be classified as solids, liquids, or gases based on whether their shapes and volumes are definite or variable. Materials can be classified as solids, liquids, or gases based on whether their shapes and volumes are definite or variable. Solid – definite shape and definite volume Solid – definite shape and definite volume Liquid – definite volume but not a definite shape Liquid – definite volume but not a definite shape Gas – neither definite shape or volume Gas – neither definite shape or volume See page 68 – Reading Strategy See page 68 – Reading Strategy

Other States of Matter Plasma – exists at extremely high temperatures Plasma – exists at extremely high temperatures BEC (Bose-Einstein condensate) – exists at very low temperatures (below -273ºC) BEC (Bose-Einstein condensate) – exists at very low temperatures (below -273ºC)

Kinetic Theory Kinetic – from the Greek meaning “to move” Kinetic – from the Greek meaning “to move” Kinetic energy – energy an object has due to its motion Kinetic energy – energy an object has due to its motion The kinetic theory of matter says that all particles of matter are in constant motion. The kinetic theory of matter says that all particles of matter are in constant motion. There are forces of attraction among the particles in all matter. There are forces of attraction among the particles in all matter.

The Kinetic Theory and the States of Matter Gases – particles are very far apart from one another and move very fast. Attraction between particles is almost non-existent Gases – particles are very far apart from one another and move very fast. Attraction between particles is almost non-existent Liquids – particles are close together and move much slower. There is attraction between particles Liquids – particles are close together and move much slower. There is attraction between particles Solids – particles are very close together and hardly move at all. Particles are very attracted to each other. Solids – particles are very close together and hardly move at all. Particles are very attracted to each other.

Explaining the behavior of Gases Gas particles are far apart and moving very, very fast Gas particles are far apart and moving very, very fast The constant motion of the gas particles allows a gas to fill a container of any shape and size The constant motion of the gas particles allows a gas to fill a container of any shape and size

Explaining the Behavior of Liquids A liquid takes the shape of its container because particles in a liquid can flow to new locations. A liquid takes the shape of its container because particles in a liquid can flow to new locations. The volume of a liquid is constant because forces of attraction keep the particles close together. The volume of a liquid is constant because forces of attraction keep the particles close together.

Explaining the Behavior of Solids Solids have a definite volume and shape because particles in a solid vibrate around fixed locations. Solids have a definite volume and shape because particles in a solid vibrate around fixed locations.

Section 3.2 The Gas Laws

Pressure Pressure is the result of a force distributed over an area. Pressure is the result of a force distributed over an area. SI unit is derived from units for force and area (force/area – Newton/square meter) SI unit is derived from units for force and area (force/area – Newton/square meter) Pascal (Pa = N/m 2 ) Pascal (Pa = N/m 2 ) Collisions between particles of a gas and the walls of the container cause the pressure in a close container of gas. Collisions between particles of a gas and the walls of the container cause the pressure in a close container of gas.

Factor that Affect Gas Pressure Temperature – raising temperature will increase its pressure if the volume & number of particles stay the same. Temperature – raising temperature will increase its pressure if the volume & number of particles stay the same. Volume – reducing the volume increases its pressure if the temperature and number of particles stay the same. Volume – reducing the volume increases its pressure if the temperature and number of particles stay the same. Number of Particles – increasing the number of particles will increase the pressure if the temperature stays the same. Number of Particles – increasing the number of particles will increase the pressure if the temperature stays the same.

Charles Law Named for Jacques Charles ( ) who studied the relationship between volume and temperature around the turn of the 19 th century. Named for Jacques Charles ( ) who studied the relationship between volume and temperature around the turn of the 19 th century. Determined that for the same amount of gas at a constant pressure, volume divided by temperature equals a constant. Determined that for the same amount of gas at a constant pressure, volume divided by temperature equals a constant. See Wok and Balloons on Chem Alive

Charles’ Law Formula V 1 V 2 V 1 V 2 T 1 T 2 T 1 T 2 In other words, they are directly proportional. In other words, they are directly proportional. = _______

Boyle’s Law Named for Robert Boyle ( ), who studied the relationship between pressure and volume in the mid-1600’s Named for Robert Boyle ( ), who studied the relationship between pressure and volume in the mid-1600’s For the same amount of gas at a constant temperature, pressure times volume equals a constant. For the same amount of gas at a constant temperature, pressure times volume equals a constant. Shows relationship between Pressure (P) and Volume (V) at constant temperature. Shows relationship between Pressure (P) and Volume (V) at constant temperature. See Easter Bunnies on Chem Alive Labs

Boyle’s Law Formula P 1 x V 1 = P 2 x V 2 P 1 x V 1 = P 2 x V 2 In other words they are inversely proportional In other words they are inversely proportional Popping packing bubbles Popping packing bubbles

Section 3.3 Phase Changes

The reversible physical change that occurs when a substance changes from one state of matter to another The reversible physical change that occurs when a substance changes from one state of matter to another Melting, freezing, vaporization, condensation, sublimation, and deposition are six common phase changes. Melting, freezing, vaporization, condensation, sublimation, and deposition are six common phase changes. The temperature of a substance does not change during a phase change. The temperature of a substance does not change during a phase change.

Energy & Phase Changes Energy is either absorbed or released during a phase change. Energy is either absorbed or released during a phase change. Endothermic change – the system absorbs energy from its surroundings Endothermic change – the system absorbs energy from its surroundings Exothermic change – the system releases energy to its surroundings Exothermic change – the system releases energy to its surroundings Heat of fusion – the amount of energy needed for a particular substance to undergo a phase change Heat of fusion – the amount of energy needed for a particular substance to undergo a phase change

Phase Changes United Streaming Video: “Physical Science Series: Phases of Matter”

Melting & Freezing The arrangements of molecules in water becomes less orderly as water melts and more orderly as water freezes The arrangements of molecules in water becomes less orderly as water melts and more orderly as water freezes The melting and freezing points of any substance are the same! The melting and freezing points of any substance are the same!

Vaporization Vaporization – the phase change in which a substance changes from a liquid into a gas Vaporization – the phase change in which a substance changes from a liquid into a gas Evaporation – a type of vaporization that occurs below the boiling point of a substance Evaporation – a type of vaporization that occurs below the boiling point of a substance Heat of vaporization – the amount of energy needed to change a substance from a liquid to a gas Heat of vaporization – the amount of energy needed to change a substance from a liquid to a gas Vapor pressure – the pressure caused by the collision of vapor and a container Vapor pressure – the pressure caused by the collision of vapor and a container

Boiling Point Boiling of a liquid occurs when the vapor pressure becomes equal to atmospheric pressure. Boiling of a liquid occurs when the vapor pressure becomes equal to atmospheric pressure. See Phase Change on Chem Alive

Condensation Condensation – phase change in which a substance changes from a gas or vapor to a liquid Condensation – phase change in which a substance changes from a gas or vapor to a liquid

Sublimation and Deposition Sublimation – phase change in which a substance changes from a solid to a gas or vapor without changing to a liquid first Sublimation – phase change in which a substance changes from a solid to a gas or vapor without changing to a liquid first Deposition – when a gas or vapor changes directly into a solid without first changing to a liquid Deposition – when a gas or vapor changes directly into a solid without first changing to a liquid