Solids, Liquids & Gases

1. Solids, Liquids & Gases

2. Standards • Be able to identify the four states of matter based on volume, shape, and particle arrangement • On a state of change graph, be able to identify heat of fusion and heat of vaporization • Be able to calculate density, given mass and volume

3. What is matter? Anything that has mass and takes up space

4. Kinetic Theory I. Kinetic theory – explains how particles in matter behave.

5. A. Based on a few assumptions • All matter is composed of small particles • Particles are in constant, random motion • Particles collide with each other and walls of their containers

6. B. Thermal energy – total energy of a material’s particles; causes particles to vibrate in place. Lower temperature means less thermal energy which means particles move slower

7. C. Average kinetic energy – temperature of the substance, or how fast the particles are moving; the higher the temp, the faster the movement.

8. D. States of Matter Ex. Sporting event

9. 1. Solid state –particles are closely packed together in a specific type of geometric arrangement.

10. Solid State a.Strong attraction between particles b.Definite shape c.Definite volume d.Particlesvibrate in place

12. 2. Liquid state – a solid begins to liquefy at the melting point as the particles gain enough energy to overcome their ordered arrangement

13. Liquid State • Attractive forces strong enough to keep particles clinging together • Definite volume • No definite shape

15. Heat of fusion - energy required to reach the melting point. Melting point – the temperature at which a solid begins to liquefy.

16. 3. Gaseous state – a liquid’s particles have enough energy to escape the attractive forces of the other particles in the liquid

17. Gases • No fixed volume • No fixed shape • Attractive forces are overcome between molecules

20. E. Vaporization • Process of particles entering the gas state is known as vaporization • Vaporization occurs in two ways: 1. evaporation 2. boiling

21. 1. Evaporation • Evaporation – vaporization that occurs at the surface of a liquid • Evaporation occurs at temperatures below boiling point • Boiling point – the temperature at which a liquid begins to vaporize. • Particles have to have enough kinetic energy to evaporate

22. 2. Boiling – occurs throughout the liquid. • At the boiling point, the pressure of a liquid’s vapor is equal to the pressure of the atmosphere, and the liquid becomes a gas • Heat of vaporization is the energy required for a liquid at boiling point to change to a gas

23. Heating Curves • Heating curve of a liquid shows the temperature change of water as thermal energy or heat is added

24. F. Diffusion • Diffusion – the spreading of particles throughout a given volume until they are uniformly distributed. • Can occur in solids and liquids, but mostly in gases • Ex. Air freshener

26. 4. Plasma – state of matter consisting of high-temp gas with balanced (+) and (-) charged particles.

29. Why are there lines/seams in concrete bridges, driveways, or sidewalks?

30. II. Thermal expansion – increase in the size of a substance when the temperature increases.

31. 1. The size of a substance will then decrease when the temp decreases and vice versa. • Bimetallic strip

32. 2. Expansion & contraction occur in most solids, liquids, and gases

33. 3. Exceptions A. Water expands as it becomes a solid because it has a polar bond ex. potholes

35. When freezing, water molecules arrange themselves based on the charge of molecules. • This leaves empty spaces in the molecule. • Empty spaces are larger in ice than liquid

36. Other exceptions: B. Amorphous solids – lack the tightly ordered structure found in crystals. • Do not have definite temp at which they change from solid to liquid • Ex. Glass, plastic

37. C. Liquid crystals do not lose their ordered arrangement completely upon melting • Used in liquid crystal displays in watches, clocks, calculators & some notebook computers

39. Questions • How can a frozen, solid ice cube have motion? • Yes it can have motion. It has motion by vibrating in place. • What causes the particles to have motion? • Thermal energy causes them to vibrate. • What happens to the thermal energy when temperature is lowered? As a result do the particles move faster or slower? • When temperature is lowered, the particles have less thermal energy, and vibrate more slowly.

40. Questions • Which will move slower? • A) molecules of frozen water at 0C • B) molecules of water at 100C • Which has lower average kinetic energy? • “A” has lower average kinetic energy because it is moving slower • How are kinetic energy and temperature related? • Temperature is the average kinetic energy of the molecules of a substance

41. MORE Questions • What is heat of fusion? • Amount of energy needed to go from solid to liquid phase • Why do liquids flow? • Particles have gained enough kinetic energy to partially escape the attractive forces in the solid • How does external pressure affect the boiling point of a liquid? • The higher the atmospheric pressure, the higher the boiling point

42. Even MORE Questions • How do liquids become a gas? • Particles in liquid are constantly moving. Some are moving faster and have more kinetic energy. Particles move fast enough to break attractive forces of other particles and enter gas state.