Chapter 3 Phases of Matter Physical Science

Transcription

1 Chapter 3 Phases of Matter Physical Science CH 3- States of Matter 1

2 What makes up matter? What is the difference between a solid, a liquid, and a gas? What kind of energy do all particles of matter have? Kinetic theory Kinetic Theory 3 Parts 1. All matter is made of tiny particles. 2. These tiny particles are always in motion. The higher the temperature, the faster the particles move. 3. At the same temperature, more massive (heavier) particles move slower Animation CH 3- States of Matter 2

3 Kinetic Molecular Theory: This motion is different for the 3 states of matter. Copyright 2010 Ryan P. Murphy Kinetic theory State the three parts of Kinetic Theory 6 CH 3- States of Matter 3

4 States of Matter States of Matter When a substance changes from one phase of matter to another, the identify of the substance does NOT change. Water freezes to a solid and melts to a liquid, but it is still just water. Microscopic view of matter CH 3- States of Matter 4

5 Activity! Describing Solid-Liquid-Gas Please fill out the following spreadsheet and then collect data. Find it or write (?) Solid Liquid Gas Volume L*W*H Shape Mass Copyright 2010 Ryan P. Murphy Activity! Describing Solid-Liquid-Gas Possible Answers! Solid Liquid Gas Volume Easy to find in ml or cm3 Easy to find. Use graduated cylinder ml Difficult to find in a classroom. Shape Many different forms. Easy to mold. Takes shape of the container. No Shape Mass Generally Heavy / Weigh in grams Easy to find. Generally Heavy / Weigh in grams. Lighter in mass / Harder to weigh in a classroom Copyright 2010 Ryan P. Murphy CH 3- States of Matter 5

6 States of Matter SOLIDS Characteristics of Solids Solids have a definite shape and volume The particles are held closely together by strong attractions Packed close together Vibrate in place. Don t flow Fill in the blanks Solids have a rigid structure. They do not need a container to maintain shape. But they can still vibrate in place. CH 3- States of Matter 6

7 Characteristics of Solids Definite volume and a definite shape. Particles are packed close together in relatively fixed positions. Particles are held by strong attractive forces between them. Particles vibrate about in a fixed position. States of Matter LIQUIDS Characteristics of Liquids 1. Has a definite volume but no definite shape. Volume remains the same, but shape changes. 2. Take shape of container. 3. Particles are held close together but can flow freely. 4. The particles in a liquid move much faster than in a solid. This allows the particles of a liquid to temporarily overcome the attractive forces between them. CH 3- States of Matter 7

8 Liquids can fill the bottom of their container. Particles are close together, but not as close as particles in a. solid CH 3- States of Matter 8

9 Characteristics of Liquids Definite volume and not definite shape. Particles are close together Takes shape of container Particles flow freely and slide past each other GASES States of Matter Characteristics of Gases CH 3- States of Matter 9

10 gas A expands to fill any available space. Gases can exert pressure on their container. These particles are approximately 10 times farther apart than those of a liquid or solid. Characteristics of Gases Gases Attractive forces between gas particles are much weaker than those in liquids and solids. Gases Particles move very rapidly and are at great distance from one another. Gases No definite shape nor definite volume. CH 3- States of Matter 10

11 States of Matter PLASMA Characteristics of Plasma High-energy plasma collides with gas particles. Ionized gas that emits electrons. PLASMA States of Matter Plasmas are similar to gases but have some properties that are different. Example: plasmas conduct electric current, while gases do NOT! The glow of fluorescent light is caused by artificial plasma which is formed by passing electric currents through gases. CH 3- States of Matter 11

12 Energy s Role Energy is the ability to change or move matter, or to do work. The energy of motion is called kinetic energy Because atoms and molecules are always in motion, all particles of matter have kinetic energy. CH 3- States of Matter 12

13 Energy s Role Gas Which is a solid, which is a liquid, and which is a gas? Solid Liquid CH 3- States of Matter 13

14 Identify as a Solid, Liquid, Gas, Plasma Copyright 2010 Ryan P. Murphy CH 3- States of Matter 14

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19 Chapter 3.2 Changes of State What happens when a substance changes from one state of matter to another? What happens to mass and energy during physical and chemical changes? Energy and Changes of State The identity of a substance does not change during a change in state The ability to change or move matter As you add energy to a liquid, the temperature goes up separating molecules Some changes of state require energy Melting, evaporation and sublimation CH 3- States of Matter 19

20 Energy and Changes of State The change of state from a liquid to a gas Boiling Point- The temperature at which a liquid boils. The temperature of boiling water is 100 o C on the celsius scale and 212 o F on the Fahrenheit scale. The temp in the room is about 22 C and 70 F. Are the following temperatures hot or cold? 65 F CH 3- States of Matter 20

21 Sublimation The process in which a solid changes directly into a gas Ex. Dry ice (Carbon dioxide in the solid form) changes directly from a solid to a gas Video Clip Melting Point The temperature at which a substances changes from solid to liquid. 32 degrees F 0 degrees C Melting point depends on the pressure. CH 3- States of Matter 21

22 Energy is released in some changes of state Freezing and condensation Name the physical phase change Melting Freezing Sublimation Evaporation Condensation Copyright 2010 Ryan P. Murphy CH 3- States of Matter 22

23 Melting sublimation Boiling or Solid Liquid evaporation Gas Freezing Condensation CH 3- States of Matter 23

24 Why are the arrows on each side of the graph the same length? Look at the vertical lines. What is the energy doing if it is not increasing the temperature? 47 Energy of System CH 3- States of Matter 24

25 Please sketch the following into your notes Copyright 2010 Ryan P. Murphy Joke of the Day What is the name of the first electricity detective? Sherlock Ohms CH 3- States of Matter 25

26 Energy Deposition Sublimation Energy Copyright 2010 Ryan P. Murphy Copyright 2010 Ryan P. Murphy CH 3- States of Matter 26

27 The temperature of a substance does not change during a change of state. For example, if you add energy to ice at 0 o C, the temperature will NOT rise until all of the ice has melted. When energy is added Move up a step. When energy is removed Go down a step. Boiling Water Vapor 100 Temperature ( o C) 0 Ice Water Heat added Melting Copyright 2010 Ryan P. Murphy CH 3- States of Matter 27

28 Latent Heat: The energy absorbed or released when a substance changes its physical state. Temperature ( o C) Latent Heat Boiling Water Latent Heat Water Vapor Ice Melting Heat added Copyright 2010 Ryan P. Murphy Conservation of Mass and Energy Mass cannot be created or destroyed. Matter can change form, and turn into different forms, but the TOTAL mass stays the same. Gas has mass! CH 3- States of Matter 28

29 Conservation of Mass and Energy The Law of conservation of energy Energy cannot be created or destroyed. Energy can convert from one form to another, but the TOTAL energy, before and after the change, is the same. Conservation of Mass and Energy Law Conservation of Matter In any physical or chemical change, matter is neither created nor destroyed Matter can be changed from one form to another. Heat Copyright 2010 Ryan P. Murphy CH 3- States of Matter 29

30 Law Conservation of Matter Copyright 2010 Ryan P. Murphy Chapter 3.3 Fluids How do fluids exert pressure? What force makes a rubber duck float in a bathtub? What happens when pressure in a fluid changes? What affects the speed of a fluid in motion? CH 3- States of Matter 30

31 Fluids A nonsolid state of matter in which the atoms or molecules are free to move past each other. Liquids and gases are fluids, because their particles can move past each other. Pressure Pressure is the amount of force exerted on a given area of surface. Fluids exert pressure evenly in all directions. How does the pressure change if you remove some of the air? CH 3- States of Matter 31

32 Pressure Pressure = force area P = F A The SI unit of pressure is the pascal. One pascal (1 Pa) is the force of one newton exerted over an area of one square meter (1N/m 2 ). The newton is the SI unit of force. Blaise Pascal Buoyant Force Buoyancy is the force with which a more dense fluid pushes a less dense fluid substance upward. How does this relate to me? Buoyancy tells me whether or not an object will float. All fluids exert an upward buoyant force on matter. Archimededs principle is used to find buoyant force. CH 3- States of Matter 32

33 Archimedes Principle Buoyant Force The buoyant force on an object in a fluid is an upward force that equals the weight of the fluid that the object displaces. Archimedes Principle Explains why a steel ship floats! 66 CH 3- States of Matter 33

34 Buoyant Force Density An object will float or sink based on its density. You can determine if a substance will float or sink by comparing densities. Pascal s Principle A change in pressure at any point in an enclosed fluid will be transmitted equally to all parts of the fluid. P=force/ area Hydraulic devices are based on Pascal s Principle. CH 3- States of Matter 34

35 Fluids In Motion Fluids move faster through small areas than through larger areas. Rates at which they flow also varies. Viscosity is the resistance of a fluid to flow. Stronger attraction between particles, the more viscous How does this relate to me? Viscosity tells me how thick a liquid or gas is. Which has a greater viscosity? Water or honey 70 CH 3- States of Matter 35

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37 Chapter 3.4 Behavior of Gases What are some properties of gases? How can you predict the effects of pressure, temperature, and volume changes on gases? Think about this. The gas in the toy balloon expands outward, as shown below. After this expansion, does the pressure of the gas a. increase? b. decrease? c. remain unchanged? Volume goes up Pressure goes down The temperature of the water vapor in the pressure cooker increases. Does the pressure of the gas a. increase? b. decrease? c. remain unchanged? Temperature increases Pressure increases CH 3- States of Matter 37

38 Properties of Gases Have low densities and are compressible. Mostly empty space. Gases fill containers uniformly and completely. Gases diffuse and mix rapidly. Gases Laws The gas laws will help you understand and predict the behavior of gases in specific situations. Boyle s Law (relates pressure to volume) Gay-Lussac s Law (relates pressure to temperature) Charles s Law (relates temperature to volume) CH 3- States of Matter 38

39 Boyle s Law Boyle s law relates the pressure of a gas to its volume. For a constant temperature, as the pressure goes up the volume goes down. As the volume goes up the pressure goes down. Pressure Temperature is constant Volume Gases Laws Robert Boyle ( ). Son of Earl of Cork, Ireland. Boyle s Law A bicycle pump is an example. Gases Laws As the volume of the air trapped in the pump is reduced, its pressure goes up, and air is forced into the tire. CH 3- States of Matter 39

40 Boyle s Law Gases Laws (pressure 1 ) (volume 1 ) = (pressure 2 ) (volume 2 ) P 1 V 1 = P 2 V 2 The gas in a balloon has a volume of 7.5 L at kpa. In the atmosphere, the has expands to a volume of 11 L. Assuming a constant temperature, what is the final pressure in the balloon? V 1 = P 1 = V 2 = P 2 =? V 1 = 7.5 L P 1 = kpa V 2 = 11 L P 2 =? P 1 V 1 = P 2 V 2 P 2 = P 1 V 1 V 2 P 2 = (100.0 kpa)(7.5 L) 11 L P 2 = 68 kpa Gases Laws Gay-Lussac s Law Relates gas pressure to temperature. The pressure of a gas increases as the temperature increases. If the volume of the gas does not change. The pressure decreases as the temperature decreases. Volume is constant Pressure Temperature P lower in winter than summer CH 3- States of Matter 40

41 Charle s Law Gases Laws Charles s law relates temperature to volume. For a fixed amount of gas at a constant pressure, the volume of the gas increases as the gas s temperature increases. Likewise, the volume of the gas decreases as the gas s temperature decreases. Pressure is constant Volume Temperature Charles s Law CH 3- States of Matter 41