Chapter 3. Solids, Liquids, and Gases

Transcription

1 Chapter 3 Solids, Liquids, and Gases

2 Section 1: States of Matter Learning Objectives: Describe the characteristics of a solid Describe the characteristics of a liquid Describe the characteristics of a gas

3 is anything that has mass and.,, and may be elements, compounds, or mixtures. A has a definite shape and a definite. The that make up a solid are packed together.

4 Each particles is tightly in. This, arrangement of particles causes a solid to have a definite and. Solids are made up of crystals called solids. Examples: Salt Sugar

5 When a crystalline solid is heated, it at a specific temperature. In solids, particles are not arranged in a regular pattern. Examples: Rubber

6 Amorphous solids melt at a distinct temperature. May become softer or into other substances.

7 A has a definite volume but no shape of its own. A liquid has. Particles in a liquid are packed as closely as in a solid but they. Example: Marbles in hand

8 A liquid is also called a meaning a substance that flows because the particles allow a to from place to place. Properties of Liquids: Surface Tension

9 is the result of an pull among the of a liquid that brings the molecules on the surface closer. Example: Water droplets on a leaf (acts as a skin) Sewing needle

10 is the liquid s to flowing. A liquid s viscosity depends on the and of it s particles and the between the particles. Liquids with high viscosity flow. Example: Honey

11 Liquids with viscosity flow. Examples: Water

12 is also a fluid. Gas volume easily. Inside a closed container, gas particles will or be together. Example: Deep breath in: chest expands, lungs fill with air Air is a of gases that act as gas. Air moves from your mouth to your windpipe to your lungs. In each place, the air has a shape.

13 If you could see the particles that make up, you would see them. Particles are no longer limited by the. As they move, spread apart, filling all space available. Gas has neither definite nor definite.

14 Section 2: Changes of State Learning Objectives: Explain what happens to a substance during changes between solid and liquid Explain what happens to a substance during changes between liquid and gas Explain what happens to a substance during changes between solid and gas

15 Particles of a liquid have more energy than particles of the same substance in form. As a, the particles of this same have even more thermal energy. A substance state when its thermal energy or decreases sufficiently. A change from to involves an in thermal energy.

16 A change from to solid involves a in energy. The change in state from solid to liquid is called. is when pure substances melts at a temperature. Melting point of pure water is.

17 Formula: Celsius to Fahrenheit Fahrenheit to Celsius

18 Thermal energy makes water molecules faster, raising their. At its, the particles of a substance are vibrating so fast that they free from their fixed positions.

19 The change of a to a is called freezing. At its freezing temperature, the particles of a liquid are moving so that they begin to form patterns. In the freezer, the liquid water energy to the cold air. The water move more and more slowly as they lose energy.

20 The change from liquid to gas is. Vaporization takes place when the particles in a gain enough to form a gas. There are two main types of vaporization: Evaporation is when vaporization takes place only on the of a liquid.

21 Example: Shrinking puddle gains energy from the ground, air, or sun. The added energy enables some of the water on the surface of the puddle to or. occurs when a liquid changes to a gas its as well as at the surface. The temperature at which a liquid boils is.

22

23 Chemists use boiling points to help identify an unknown substance. Boiling point depends on the of the air above it. The the pressure, the energy needed for the particles of the liquid to escape into the air. At sea level, boiling of water is C ( 0 F). In the mountains, air pressure is lower, so is water s boiling point. In Denver, elevation is 1600 m above sea level, water boils at F ( 0 C).

24 The opposite of vaporization is. Observing condensation by breathing onto a mirror. When warm in your breath reaches the surface of the mirror, the water vapor into liquid droplets. Condensation occurs when in a gas enough energy to form a.

25

26 Example: Clouds form when water vapor in the atmosphere condenses into liquid droplets. When droplets become too heavy, they fall to the ground in the form of rain. Water Vapor: Can t see gas Is not the over kettle of boiling water Not clouds or fog (tiny droplets of liquid water suspended in air

27

28 occurs when the surface particles of a solid gain enough energy that they form a. During sublimation, particles of a solid pass through the state as they form a gas.

29 Example: Dry ice (Solid CO 2 ) Can t exist as liquid at ordinary atmospheric pressures CO 2 changes directly into a instead of melting and absorbs. Keeps temperature Cools in nearby air Water vapor then into a liquid forming a fog

30 Section 3: Gas Behavior Learning Objectives: List the types of measurements used when working with gases Explain how the volume, temperature, and pressure of a gas are related.

31 Gases easily or When working gas you should know: Volume Pressure is the amount of space that matter fills and is measured in (cm 3 ), (ml), and liters (L).

32 The volume of a is the same as the of its container. Temperature is a measure of the energy of random motion of the particles of a substance. The the particles are moving, the their energy, and the the temperature. Thermometer = speedometer for molecules

33 The of the gas is the force of its outward push divided by the area of the walls of the container. Pressure is measured in units of (Pa) or kilopascals (kpa). 1 kpa = Pa (Metric system scale)

34 Formula: Pressure = Force (Newtons) Area (Meters 2 ) Firmness of gas-filled object comes from of gas. Example: Air inside fully pumped basketball has a higher pressure than the air outside. Higher pressure is due to greater (number of particles in a given unit of volume) of gas particles inside When air leaks, the pressure, ball becomes softer

35

36 Example 1: A machine exerts a force of 252 N on a piston having an area of m 2. What is the pressure on the piston in Pa? Example 2: A trash compactor exerts a force of 5,600 N over an area of m 2. What pressures does the compactor exert in Pa?

37 Boyle s Law Measured the volumes of gases at different pressures When the pressure of a gas at constant temperature is, the volume of the gas. When the pressure is, the volume. Least pressure, greatest volume Increasing pressure, decreasing volume Greatest pressure, least volume

38 Gas particles travel individually and at high speeds. The the gas particles move, the more frequently they with the walls of their container and the the force of the collisions. When the temperature of a gas at constant volume is, the of the gas increases. When the temperature is, the pressure of the gas.

39 Example: Tires on an 18-wheel truck

40 Charles s Law Relationship between and of a gas that is kept at constant pressure Changeable volume allows the pressure to remain constant Temperature of a gas is at constant volume pressure, its increases. When temperature of a gas is decreased at constant pressure, its volume decreases.

41 Charles s Law Higher temperature, greater volume. Lower temperature, smaller volume

42 Section 4: Graphing Gas Behavior Learning Objectives: Identify the type of relationship shown by the graph for Charles s Law Identify the type of relationship shown by the graph for Boyle s Law

43 A is a diagram that tells how two variable are related. Graph consists: Horizontal line (x-axis) Variable Vertical (y-axis) Variable Divided into equal units

44 Law relates to the temperature and of a gas that is kept at a pressure. When a graph of two variables is a straight line passing through the origin, the variables are said to be to each other. Charles s Law shows that the is directly proportional to its kelvin temperature under constant pressure.

45 When a graph of two variables forms a, the variables are said to. shows that the pressure of a gas varies inversely with its volume at constant temperature.

46 kpa Charles s Law Boyle s Law ml