Chapter 8 Solids, Liquids, and Gases

1. Chapter 8 Solids, Liquids, and Gases

2. Objectives • 8.1Describe the four states of matter • 8.1 Use the kinetic theory of matter to explain the characteristics of solids, liquids, and gases • 8.1 Explain the thermal expansion of matter

3. Objectives • 8.2Describe how people use and pollute water • 8.2Discuss how people can save water and stop pollution • 8.3 Interpret state changes in terms of the kinetic theory of matter • 8.3 Account for the energy of the heats of fusion and vaporization in state changes

4. States of Matter • Solid • Fixed Volume, Fixed Shape, Incompressible, Strong Forces • Liquid • Fixed Volume, Flexible Shape, Incompressible, Weak Forces • Gas • Flexible Volume, Flexible Shape, No Forces

5. States of Matter • Dictated by • Temperature • Higher Temperatures favor Gas • Pressure • Higher Pressures favor solids • Forces present between matter • Large forces favor solids • Kinetic Theory of Matter: Tiny particles (that make up matter) are constantly in motion.

6. States of Matter • Which state of matter has the most energy at room temperature? • Is it the table (solid)? • Is it the water (liquid)? • Is it the air (gas)?

7. State of Matter • All states of matter have the same amount of energy • Temperature is a measure of kinetic energy. As long as two substances have the same temperature, they have the same amount of energy • The table molecules are larger, move slower • The air molecules are smaller, move faster

8. Solids • Two types • Crystalline Solids • Repeating Pattern • Amorphous Solids • No form, no repetition

9. Examples • Crystalline Solids • Salts, snowflakes • Amorphous Solids • Wax, plastics, glass • Some people consider these to be “thick liquids”

10. Liquids • Close together, but able to move freely around one another • Incompressible but able to change shape

11. Gases • Very far apart, no attraction to other molecules • Expand to fill volume • Very variable density (can be compressed) • To put the gas in perspective: Water as a liquid, compared to water as a gas. The liquid water is 1200x more dense

12. Plasma • State of matter where the particles become charged (ionized). • The nucleus is separated from some of the electrons • Most common state of matter in universe, (99%) of universe • The sun • Has to be very hot • Not in your stove, try a few million degrees

14. Thermal Expansion • As substances heat up, they increase in size • Kinetic Theory: If the molecules move more, they take up more space. • If a kid eats a donut, they take up more space… • Bridges (gaps), Thermometers (liquid expands), Houses creak at night (as they shrink in size)

15. Thermal Expansion • Leads to convection in boiling water • Leads to gases having very different densities • Think Hot Air Balloons • Caused the St.Louis Arch to not fit the first time • Called up the Fire Department

16. Water Pollution and Water Issues • How much water do we use on a daily basis? • What/who are the culprits for polluting water? • How clean is USA drinking water anyway? • Is there enough fresh water to go around? • Should our water usage be more regulated?

17. Phase Changes • When a substance changes state of matter, it is called a phase change • The molecules don’t change, they just change how they are bonded • If you boil water, you are not changing the water into another substance, it is still water • Does freezing take energy or release energy? • How do orange farmers keep the crops safe when it is cold?

18. Changes of States • Solid to Liquid  Melting • Solid to Gas  Sublimation • Dry Ice and Moth Balls • Liquid to Gas  Evaporation • Gas to Liquid  Condensation • Gas to Solid  Deposition • Frost • Liquid to Solid  Freezing

19. How much heat to evaporate? • Heat of Vaporization: Energy required to make a substance evaporate • Also energy released when condensing • Heat of Fusion: Energy required to make a substance melt • Also energy released when freezing

20. Lots of energy to evaporate • Why we feel cold after being in the pool

23. End Notes for Quiz 8.1 – 8.3

24. Objectives • 8.4Explain how a gas exerts pressure on its container • 8.4 State and explain how the pressure of a container of gas is affected when the volume is changed • 8.4 Explain the relationship between temperature and the volume of gas

25. Objectives • 8.5State Archimedes principle and predict whether an object will sink or float in water • 8.5 State Pascal's principle and describe the operation of a machine that uses Pascal's principle • 8.5 State Bernoulli's principle and describe a way that Bernoulli's principle is applied

26. F A P = Pressure • Pressure is the amount of force applied to an area. • Measured in Pascals

27. Weight of the Atmosphere • Varies on a regular basis • High and Low pressure • Varies by location • Mountains have less air on top • less pressure = lower BP • Some people claim that they can detect these changes… myth or fact?

28. Pressure • Increase Temperature: More Pressure • Increase the amount of molecules: More Pressure

29. What is the pressure (in PSI) • On your feet? • On an elephant’s feet? • On a high heel shoe?

30. Boyle’s Law • Boyle’s Law: A law which relates how volume and pressure of a gas are related • Pressure goes up, volume goes down

31. Boyle’s Law Examples • Pertinent to our breathing. • How big of a pressure difference do you think our chest cavities can create? • What is the volume of your lungs when fully inhaled? • What is the volume of your lungs when fully exhaled? • Explain how a vacuum works

32. Boyle’s Law Examples • Relevant to weather balloons • As the balloon rises, the pressure on the outside decreases, the balloon expands so that the pressure inside is the same as the outside • At approximately 15 km, the altitude is 1/10 of sea level, so the balloon will expand to a volume of 10x its original • Balloons pop at certain height

33. Boyle’s Law Examples • Relevant to deep sea divers • 10 m of water depth is equal approximately to the atmosphere • At high pressure, gas is forced into the blood stream easier. Later on, when you return, the gas in the vessels and arteries expands, called the Benz

34. Boyle’s Law Examples • Relevant to medicine • Hyperbaric chambers: High pressure container designed to help the body heal • Used by sports teams, used to treat premature babies, used for patients after heart attacks • Some Young Earth Creationists speculate that before the flood, pressure was larger allowing for large animals to exist • Used for bigger plants too (super green house)

35. Charles Law • Charles Law: A law which relates how volume and temperature of a gas are related • As Temperature goes up, the volume goes up • Think Hot Air Balloons. More volume = Less Density

36. Buoyancy • Buoyant Force: The ability of a fluid to exert an upward force on an object immersed in it • Based on Densities dictates how much lift you get

37. Archimedes Principle • Archimedes Principle: Buoyant force on an object is equal to the weight of the fluid displaced • If the object has a weight of 50 g, it will displace 50 g of water (if it floats)

38. Only works if you are floating

39. Pascal’s Principle • Pascal’s Principle: A principle which states that pressure exerted on a fluid is transferred to another location unchanged through the fluid

40. Mechanical Advantage

41. Bernoulli’s Principle • Bernoulli’s Principle: A principle which relates the velocity of a fluid and the pressure the fluid exerts

43. Venturi Effect • Venturi Effect: A special case of Bernoulli’s principle seen in windy cities