CHAPTER 2: SOLIDS, LIQUIDS AND GASES

1. CHAPTER 2: SOLIDS, LIQUIDS AND GASES

2. oil liquid water wood solid rock lava gas air sand What is our world made of ?

3. 1.States of Matter liquid gas solid

4. Properties of Solids • Definite shape • Definite volume • Hard to compress • Do not flow

5. Types of solids • Solids that are made up of crystals are called crystalline solids. • I.e.: salt, sugar, snow… • Amorphous solids:The particles are not arranged in a regular pattern. • They don’t melt at a distinct temperature, they may become softer or change into other substances. • I.e.: plastics, rubber and glass

6. The pictures below show the arrangement of solid particles Please identify the types of solid.

8. Properties of Liquids • No definite shape • Definite volume • Flow easily • Hard to compress

9. Properties of liquids • Surface tension is the result of an inward pull among the molecules of a liquid that brings the molecules on the surface closer together.

10. Fluid : a substance that flows • Another property of liquids is viscosity . • Viscosity depends on the size and shape of its particles and the attraction between the particles.

11. Properties of Gases • No definite shape • No definite volume • Easy to compress • Spread out to fill all available space - diffusion

12. Change of State Melting Evaporating Gas Solid Liquid Condensing Freezing Energy

13. 2. Change of State Changes Between Solid and Liquid • The temperature at which the solid melts – melting point Particles vibrate more Vibrating a little Solid melted to form liquid

14. The melting point is the temperature at which the solid and liquid states of a substance exist together

15. Changes Between Liquid and Gas Particles have enough energy to escape Particles in liquid state Particles move faster

16. The boiling point is the temperature at which evaporation begins to occur throughout the liquid, i.e. Bubbles of vapour form inside the liquid

17. Temperature Scale For Water

18. Change of State - Evaporation What happens if there are puddles on the road on a sunny day? Sun gives some particles near surface extra energy Particles have enough energy to overcome forces holding them together Break away from liquid & go into the air Some liquid has evaporated to form a gas

19. Evaporation is the changing of a liquid to a vapour that take place only on the surface of a liquid.

20. Vaporization: The change from a liquid to a gas Evaporation Vaporization Boiling

21. Question • What are the ideal conditions when hanging out clothes to dry?

22. Dry, warm and windy • Evaporation is helped by the wind • The wind blows away the particles that have already evaporated • This makes room for more particles to evaporate

23. Evaporation V Boiling Point Liquid doesn’t have to be heated to its boiling point for evaporation to occur – evaporation from surface of liquid is always taking place

25. Changes from the Gas to the Liquid: Condensation • When gas cooled. • Particles slow down, become closer to each other. • Liquid formed eventually.

26. Condensation

27. Questions • On a cold morning if you breath on the window of the car what happens? • What happens to the mirror in the bath room when you have a hot shower? • Why do they happen? • Why does butter spread more easily if it is warmed slightly? • Why do ice cubes added to a glass of lemonade slowly disappear?

28. Condensation • Steam (gas) cooled when it hits the cold mirror • Particles slow down, become closer to each other • Liquid formed eventually

29. Math Analyzing Data P53 • 1.Time on the x-axis, temperature on the y-axis. • 2.The temperature is rising from 0 ℃ to 100 ℃ • 3. Segment B: melting point of ice; • Segment D: boiling point of water • 4. Melting and Boiling • 5.Water molecules in segment E have more thermal energy because they are at a higher temperature.

30. Changes Between Solid and Gas: Sublimation • Some substances when heated change directly from solid to gas (sublimation) • Iodine and solid carbon dioxide (dry ice)

31. Particle Arrangement Liquid Gas Solid

32. 3.GAS BEHAVIOUR • When working with a gas, it is helpful to know its volume, temperature and pressure • Volume: amount of space that matter fills (cm3, ml or L) • Temperature: measure of the average energy of random motion of the particles of a substance. The faster the particles are moving, greater energy and higher temperature. • Pressure: (particles collide with one another and with the walls of their container). Force of its outward push divided by the area of the walls of the container • Pressure= Force/Area Unit: Pascal (Pa), atmosphere (atm), mmHg (millimeters of Mercury)

33. PRESSURE AND VOLUME • Boyle’s law • When the pressure of a gas at constant temperature is increased, the volume of the gas decreases. When the pressure is decreased, the volume increases. • Relationship between volume and pressure • I.e.: Balloons in the atmosphere and bicycle pump • Pressure and volume graph

34. PRESSURE AND TEMPERATURE • When the temperature of a gas at constant volume is increased, the pressure of the gas increases. And the opposite. • I.e.: Trucks tires in summer (reduce the pressure) • Pressure and temperature graph • VOLUME AND TEMPERATURE • Charles’s Law • When the temperature of a gas is increased at constant pressure, its volume increases. When the temperature of a gas is decreased at constant pressure, its volume decreases • I.e.: Balloon in the oven and freezer • Volume and temperature graph