Section 1: States of Matter How can you describe the motion of particles in a solid? How can you describe the motion of particles in a liquid? How can you describe the motion of particles in a gas?

SOLIDS: A solid has a definite shape and a definite volume. What are some examples?

Solids The particles in a solid are closely locked in position and can only vibrate, as they do not have enough energy to slide past one another.

There are 2 types of solids: Crystalline Solids Amorphous Solids

Crystalline Solids: Particles form a regular repeating pattern. These patterns create crystals. Examples: Salt, Sugar, Snow, Quartz Melts at a specific temperature

Amorphous Solids: Particles are not arranged in a regular pattern. Examples: Plastic, Rubber, Glass, Butter Does not melt at a distinct temperature, may become softer or change into other substances.

LIQUIDS: A liquid has a definite volume but not a definite shape. It takes on the shape of its container. What are some Examples?

Liquids In general, particles in a liquid are packed almost as closely as a solid, but the particles move freely. Compared to particles in a solid, the particles in a liquid are more loosely connected and can collide with and move past one another. This is why a liquid flows and has no definite shape.

Properties of Liquids: Surface Tension: Result of an inward pull among the molecules of a liquid that brings the molecules on the surface closer together Causes water to bead up and insects to walk on water Viscosity: A liquid’s resistance to flowing Depends on size and shape of particles and attraction between them High viscosity = slow flow, like honey Low viscosity = quick flow, like water

GASES: A gas does not have a definite shape or a definite volume. Gas particles can spread apart or be squeezed together depending on the container. What are some examples?

Gases In gases, the atoms and molecules are free to move independently, colliding frequently.

FLUIDS: Fluid means a “substance that flows.” Both liquids and gases are considered fluids.

LET’S REVIEW! Crystalline Solid Amorphous Solid In Which type of Solid do particles form a regular repeating pattern? Crystalline Solid What type of solid is butter? Amorphous Solid

LET’S REVIEW! Solid, Liquid, Gas Liquid What are the 3 States of Matter? Solid, Liquid, Gas Which state of matter has a definite volume, but no shape of its own? Liquid

LET’S REVIEW! Solids Low What state of matter is not considered a fluid? Solids Does juice have a high or low viscosity? Low

Section 2: Changes of State What happens to a substance during changes between solid and liquid? What happens to a substance during changes between liquid and gas? What happens to a substance during changes between solid and gas?

Thermal Energy Gases have the most thermal energy, then liquids, then solids. So changing from a solid to a liquid takes an increase in thermal energy, whereas going from liquid to solid is a decrease in thermal energy. A change in thermal energy means a change in molecular motion. Remember that particles of gases are the most free, then liquids, then solids.

Changes Between Solid and Liquid The change in state from a solid to a liquid is called melting.

Melting Solid  Liquid Occurs at a characteristic temperature called a melting point When a substance melts, the particles in the solid vibrate so fast that they break free from their fixed positions. Increased thermal energy causes the particles to vibrate faster and temperature to increase. Once the melting point temperature is reached, energy causes particles to break free and collide with one another, thus becoming a liquid. Physical change, not chemical change

Changes Between Solid and Liquid The change from a liquid to a solid is called freezing.

Freezing Liquid  Solid Occurs at a characteristic temperature called a freezing point (should be same as melting point) When a substance freezes, the particles in the liquid move so slowly that they begin to take on fixed positions. Decreased thermal energy causes the particles to lose energy and move more slowly. Eventually, the liquid becomes a solid. Not always at cool temperatures, Example: Candle wax, butter, chocolate Physical change, not chemical change

Changes Between Liquid and Gas The change from a liquid to a gas is called vaporization.

Vaporization Liquid  Gas Takes place when the particles in a liquid gain enough energy to move independently, forming a gas. When a substance freezes, the particles in the liquid move so slowly that they begin to take on fixed positions. Freedom of motion increases Physical process, not chemical 2 main types of vaporization: Evaporation and Boiling

Vaporization EVAPORATION: Vaporization that takes place only on the surface of a liquid. Example: a shrinking puddle Vaporization that takes place both below the surface and at the surface of a liquid. Bubbles form below surface and rise and break the surface. Temperature a liquid boils at is called its boiling point. Boiling point of a substance depends on the pressure of the air above it. Example: at sea level water boils at 100°C, but in mountains where air pressure is lower, it boils at 95°C BOILING:

Let’s look at these pictures again:

Changes Between Liquid and Gas The change from a gas to a liquid is called condensation.

Condensation Gas  Liquid During condensation, the particles in a gas lose enough thermal energy to forma liquid. Gas particles cannot overcome attractive forces between them, freedom of motion decreases, and they condense into a liquid. Example: clouds forming, breath on mirror Physical process, not chemical

Changes Between Solid and Gas The change from a solid to a gas is called sublimation. Does anyone know what this a picture of?

Sublimation Solid  Gas Occurs when surface particles of a solid gain enough energy that they form a gas During sublimation, particles of a solid do not pass through the liquid state as they form a gas Freedom of motion of particles increases Physical process, not chemical Example: Dry ice, disappearing of snow in temperatures below freezing

Let’s make a prediction!! If you allowed the dry ice to stand at room temperature for several hours, what would be left in the glass dish? Why? Let’s make a prediction!! Nothing would be left, because all of the carbon dioxide would sublimate and mix with the air.

Let’s Review!! True or False: All of the processes we talked about today were physical processes. What physical state is skipped during the sublimation of a substance? True! All phase changes involve only physical processes, no chemical. The liquid state.

Let’s Review!! True or False: The reverse of vaporization is melting. Evaporation is going from what state to what state? False! Vaporization is Liquid  Gas, so the reverse must be Gas Liquid, or condensation. (Melting is Solid  Liquid) Liquid  Gas

3-3 Notes Part I

Section 3: The Behavior of Gases What types of measurements are useful when working with gases? How are the volume, temperature, and pressure of a gas related?

Measuring Gases When working with a gas, it is helpful to know its volume, temperature, and pressure. Let’s think back to chapter 1 and redefine some of these terms!

Volume Volume is the amount of space that matter fills. Since gas particles move to fill up the space available, the volume of a gas is the same as the volume of it’s container. Units for Volume = cm3, mL, L, etc.

Temperature Temperature is a measure of the average energy of motion of the particles of matter. The faster the particles are moving, the more energy they have, and the higher the temperature they have. Units for temperature = K, °C, °F

Pressure Gas particles are constantly moving and pushing against the walls of their container. The pressure of the gas is the force of its outward push divided by the area of the walls of the container. Units for Pressure = pascals (Pa), or kilopascals (kPa). 1 kPa = 1,000 Pa

WHY? Pressure (continued) The firmness of a gas filled object comes from the pressure of the gas. Example: Air inside a fully pumped basketball has a higher pressure than the air outside, because there is a greater number of gas particles per unit volume inside the ball than in the air outside. WHY? Who knows what would happen if you poked a hole in the basketball?

A Change in Pressure Due to high pressure inside the ball, gas particles hit the inner walls of the ball more often, therefore reach the hole more often and escape. A punctured basketball deflates as gas particles begin to escape. The pressure inside drops until it equals the pressure outside.

Pressure and Volume If temperature is held constant, then gas pressure and volume are inversely proportional to each other. This means as one goes up, the other goes down. Example: If the volume is tripled, pressure would be 1/3 of what is was. This concept is described by Boyle’s Law.

Boyle’s Law Scientist Robert Boyle conducted experiments on air pumps to show that gas volume and pressure were related in the 1600s. Boyle’s law says that when the pressure of a gas at constant temperature is increased, the volume of the gas decreases. And when pressure decreases, volume increases.

Boyle’s Law As weights are added, the gas particles occupy a smaller volume. The pressure increases.

Graphing Boyle’s Law: This is what a basic graph of Boyle’s Law should look like. It should show a nonlinear trend. At any point on the curve, you should be able to multiply the 2 variables and get the same product. 70 X 20 = 1400 50 X 28 = 1400 This is because the relationship between the 2 variables (Pressure and Volume) is that they are inversely proportional.

3-3 Notes Part II

Temperature and Volume When pressure remains constant, then temperature and volume are said to be directly proportional to each other. This means that as temperature increases, volume increases. And as temperature decreases, volume decreases. This concept is explained by Charles’ Law.

Charles’ Law Jacques Charles was a French scientist in the 1700s who discovered the relationship between the temperature and volume of a gas. Charles’ Law states that when the temperature of a gas is increased at constant pressure, its volume increases. And when the temperature of a gas is decreased at constant pressure, its volume decreases.

Charles’ Law When the temperature of a gas increases at constant pressure, its volume increases.

Graphing Charles’ Law: This is what a basic graph of Charles’ Law should look like. The graph should show a linear trend (straight line) that passes through the origin. This is because the relationship between the 2 variables (volume and temperature) is that they are directly proportional to each other. Graphing Charles’ Law:

Pressure and Temperature When the temperature of a gas at constant volume is increased, the pressure of the gas increases. When the temperature is decreased the pressure of the gas decreases. Constant volume means that the gas is in a closed, rigid container.

Pressure and Temperature When a gas is heated, the particles move faster and collide more often with each other and with the walls of their container. The pressure of the gas increases.

QUIZ!! You are having a quiz next class over 3-3. STUDY! STUDY! STUDY!