KINETIC MODEL and THREE STATES of MATTER

Matter is anything that has mass and takes up space. What is matter? Matter is anything that has mass and takes up space.

Properties of Matter How It Looks (Shiny , Color, etc.) How It Feels (Hard, Soft, Rough, Smooth, etc.) How It Smells (Sweet, Sharp, Terrible, No Smell, etc.) How It Sounds (Loud, Soft, No Sound, etc.) What It Does (Bounce, Stretch, Break, Magnetism etc.)

Kinetic Model of Matter Matter is made up of particles which are in continual random motion.

The Kinetic Model: All matter is composed of small particles (atoms, molecules, or ions). 2. They are in constant, random motion. 3. They constantly collide with each other and with the walls of their container.

STATES OF MATTER Based on particle arrangement Based on energy of particles Based on distance between particles

SOLID A solid is matter that has definite size and shape. Example: Put a pen in a box. It stays the same.

LIQUID A liquid takes the shape of any container. Example: Pour juice into a glass. The juice will take on the shape of the glass.

GAS Gas is matter that has no definite shape. Gases take the shape of whatever container they are in . Example: The air all around us is a gas.

Phase Properties Particle Properties Phase Proximity Energy Motion Volume Shape Solid close little vibrational definite definite Liquid close moderate rotational definite indefinite Gas far apart a lot translational indefinite indefinite

PHYSICAL CHANGES

Physical changes in matter A Physical change is a change in how matter looks. Tear Cut Folded Written Liquid Solid Gas Mixture Solution

PHASE CHANGES Melting Freezing Solid to liquid Description of Phase Change Term for Phase Change Heat Movement During Phase Change Solid to liquid Melting Heat goes into the solid as it melts. Liquid to solid Freezing Heat leaves the liquid as it freezes.

PHASE CHANGES Liquid to gas Gas to liquid Condensation Solid to gas Description of Phase Change Term for Phase Change Heat Movement During Phase Change Liquid to gas Boiling and evaporation Heat goes into the liquid as it vaporizes. Gas to liquid Condensation Heat leaves the gas as it condenses. Solid to gas Sublimation Heat goes into the solid as it sublimates.

STATES OF MATTER SOLID LIQUID GAS PLASMA Tightly packed, in a regular pattern Vibrate, but do not move from place to place Close together with no regular arrangement. Vibrate, move about, and slide past each other Well separated with no regular arrangement. Vibrate and move freely at high speeds Has no definite volume or shape and is composed of electrical charged particles

MELTING AND BOILING

On the Molecular Level When molecules absorb heat energy, they will start to move faster. When the molecules have reached a certain speed, the energy that they absorb will be used to break the attractive forces between them.

On a Molecular Level When the energy absorbed is used to break the attractive forces between them, there is no increase in speed. Which means the energy absorbed can only be used for either one of the purpose (break attractive forces OR increase in speed). Only one change is taking place at any time.

So what do we see? When the energy is used to increase the speed of the molecule, we see a rise in temperature of the substance. When the energy is used to break attractive forces between molecules, we see the substance changing in state. This energy which brings about a change in state is known as LATENT HEAT

Changes in States Gas Solid CONDENSATION Loss in heat Boiling Liquid FREEZING (solidification ) Gain in heat Melting Solid

The graph shows how the temperature changes with time as a substance is heated at a constant rate. There are obvious horizontal flat sections of the graph at the melting and boiling point.

The graph shows how the temperature changes with time as a substance is heated at a constant rate. There are obvious horizontal flat sections of the graph at the melting and boiling point. Above the boiling point the substance is a gas. Above the melting point the substance is a . liquid Below the boiling point the substance is a liquid. Below the melting point the substance is a solid.

The process of melting requires extra energy - it is endothermic. At the melting point, although the substance is still being heated, there is a time when the temperature does not change and the graph is horizontal. During this time, all the extra heat which is being added goes to overcome the force of attraction (the bonds) between the particles of the solid as it turns into a liquid.

At the boiling point, although the substance is still being heated, the temperature does not change for a time and the graph becomes horizontal. During this time the extra heat that is being added goes to overcome the force of attraction  between the particles of the liquid as it turns into a gas. The process of boiling needs extra energy - it is endothermic.

MELTING AND SOLIDIFICATION When a solid changes to a liquid on heating, we call it melting. In this instance, heat is ABSORBED by the substance. When a liquid changes to a solid on cooling, we call it solidification (freezing) In this instance, heat is LOST by the substance.

MELTING AND SOLIDIFICATION In both cases, the heat that is absorbed or lost is known as the latent heat of fusion. When this latent heat is absorbed or lost, there is no change in temperature. This means when a substance is undergoing a change in state, the temperature will remain constant.

The Temperature-time Graph This part of the graph shows a constant temperature which means this is when the substance is changing state temperature time

Boiling AND condensation When a liquid changes to a gas on heating, we call it boiling. In this instance, heat is ABSORBED by the substance. When a gas changes to a liquid on cooling, we call it condensation. In this instance, heat is LOST by the substance.

Changes in States Gas Loss in heat Boiling Gain in heat Melting Liquid CONDENSATION Loss in heat Boiling Liquid FREEZING (solidification) Gain in heat Melting Solid

Boiling AND condensation In both cases, the heat that is absorbed or lost is known as the latent heat of vaporization. When this latent heat is absorbed or lost, there is no change in temperature. This means when a substance is undergoing a change in state, the temperature will remain constant.

Specific Latent Heat Recall that the energy absorbed or released causing a change in state is known as latent heat. Example: latent heat of fusion latent heat of vaporization