Lesson 11 Phases of Matter Everything around is matter A state of matter is the physical form in which matter exists

Phases of Matter There are four states or phases of matter Solid Liquid Gas Plasma

Phases of Matter Matter often changes state when heat is added or taken away.

Solids, Liquids, Gases On Earth most matter exists in three states

Solids, Liquids, Gases Liquids:

Solids, Liquids, Gases Gas:

Solids, Liquids, Gases A gas will spread out to occupy all of the space available to it. Both liquids and gases are referred to as fluids, because both have a tendency to assume the shape of whatever container holds them.

States of Matter and Their Properties Solids, Liquids, Gases Property Solid Liquid Gas Shape Definite shape No definite shape Volume Definite volume No definite volume Particle arrangement Densely packed Close Far apart Energy binding particles Very strong Strong weak States of Matter and Their Properties

Particles and Phase All matter is made up of particles called atoms and molecules. The arrangement and motion of the particles that make up a substance determine its state

Solids In a solid, particles are packed together quite closely and the energy binding these particles is very strong. This prevents the particles from moving about freely. The particles move by vibrating in their position.

Solids This is what gives a solid a definite shape and volume *

Liquids Particles in a liquid are less densely packed then those in a solid The energy binding the particles of a liquid is also weaker than that in a solid

Liquids Particles in a liquid can move around and slide past one another. The movement of the particles in a liquid prevents a liquid from having a definite shape. * Liquids do have a definite volume

Gases The energy that binds particles in gases together is weak. This allows the particles to move freely. *

Gases The free movement of gas particles allows a gas to expand or contract to fit its container. As a result, a gas lacks a definite shape and its volume is decided by the container that holds the gas.

Heat Affects the Phase of a Substance When a substance takes in heat, its particles gain energy and move more quickly. When a substance releases heat, its particles lose energy and move more slowly.

Heat Affects the Phase of a Substance If enough heat is added or removed from a substance, a change in the state of the substance occurs. Adding heat to a solid causes the particles of the solid to gain energy. * This causes the particles to move faster and farther apart.

Heat Affects the Phase of a Substance If enough heat is added, the solid will change to a liquid. When a substance changes from a solid to a liquid, it is melting The temperature at which a solid begins to change to a liquid is called its melting point.

Heat Affects the Phase of a Substance Each substance has its own melting point. Particles in a liquid also move faster and spread apart when heat is added. At a certain temperature, the particles gain enough energy that they begin to escape from the liquids surface and change to a gas.

Heat Affects the Phase of a Substance The process in which a liquid changes to a gas is called vaporization. * The temperature at which a liquid brings vaporizing or changing to a gas is called boiling point

Heat Affects the Phase of a Substance If heat is removed from a substance, its particles will lose energy, move more slowly and get closer together. * This can cause the substance to change states.

Heat Affects the Phase of a Substance Condensation is the changing of a substance from a gas to a liquid. The temperature at which a substance condenses is the same as the temperature at which it boils.

Heat Affects the Phase of a Substance The difference is in the direction that the temperature has been moving, higher (boiling) or lower (condensing)

Heat Affects the Phase of a Substance Freezing refers to a change from the liquid state to the solid state. The temperature at which liquid begins to change into a solid is called freezing point. The freezing point and melting of a substance are identical.

Heat Affects the Phase of a Substance The term used depends on in which direction the temperature of the substance has been moving. During a phases change, the temperature remains constant. The temperature changes only after all of a substance has changed from one state to another.

Heat Affects the Phase of a Substance The temperature will then rise or fall depending on whether heat is being added or removed from a substance.

Plasma The fourth state of matter is plasma. Plasma is a state of matter that forms when temperatures are high enough to remove electrons from their atoms. *

Plasma Plasma forms when a gas is heated to such a high temperature that the electrons in its atoms gain enough energy to escape from their atoms.