2. States of Matter

3. 3-1 Solids, liquids and gases Materials can be classified as solids, liquids, or gases based on whether their shapes and volumes are definite or variable

4. Solids Solid is the state of matter in which materials have a definite shape and a definite volume Definite = the shape and volume will not change ( ex: a pencil) Particles in a solid are packed tightly together.

5. Liquids Liquid is the state of matter in which a material has a definite volume but not a definite shape Ex: juices in different shaped bottles Particles are close together but have a little room to move

6. Gases Gas is the state of matter in which material has neither a definite shape nor a definite volume Gas takes the shape and volume of its container

7. Kinetic Theory Kinetic energy is the energy an object has due to its motion The faster an object moves, the greater the kinetic energy The kinetic theory of matter says that all particles of matter are in constant motion

8. Explaining the Behavior of Gases The particles in a gas are never at rest. There are forces of attraction among the particles in all matter Particles in a gas are moving fast and the attractions are too weak to have an effect

9. Kinetic Theory of Gases The constant motion of particles in a gas allows a gas to fill a container of any shape or size Ex: air in a tire

10. Three Key Points to Kinetic Theory of gases 1.Particles in a gas are in constant, random motion 2.The motion of one particle is unaffected by the motion of other particles unless the particles collide 3.Forces of attraction among particles in a gas can be ignored under ordinary conditions

11. Explaining the Behavior of Liquids A liquid takes the shape of its container because particles in a liquid can flow to new locations. The volume of a liquid is constant because forces of attraction keep the particles close together. Particles in a liquid are more closely packed than gases

12. Explaining the Behavior of Solids Solids have a definite volume and shape because particles in a solid vibrate around fixed locations Vibration is a repetitive back and forth motion Strong attractions among atoms restrict their motion.

13. Teacher Demo Which container has the largest volume of water?

14. Beaker Breaker Partner Activity 1.Explain how the behavior of popcorn in a popcorn popper can be used as an analogy for the motion of gas particles

15. Beaker Breaker Activity A hazardous chemical is leaking from a tank truck. Rescue workers need to evacuate people who live near the accident. Why are more people likely to be affected if the chemical is a gas, rather than a liquid?

16. Beaker Breaker 1.Explain why a solid has a definite shape and volume 2.How is a gas able to fill a container of any size or shape?

17. 3-2 The Gas Laws Pressure is the result of the force distributed over an area. Ex: A puck hitting glass Collisions between particles of a gas and the walls of the container cause the pressure in a closed container of gas. The more frequent the collisions, the greater the pressure of the gas.

18. Factors that Affect Gas Pressure Factors that affect the pressure of an enclosed gas are its Temperature Volume Number of Particles

19. Temperature Raising the temperature of a gas will increase its pressure if the volume of the gas and the number of particles are constant Temp and pressure increase Volume and number of particles are constant Ex. Tires after driving

20. Volume Reducing the volume of a gas increases its pressure if the temperature of the gas and the number of particles are constant Volume decrease/Pressure increase Temp and number of particles are constant

21. Number of Particles Increasing the number of particles will increase the pressure of a gas if the temperature and volume are constant Increase # particles/increase pressure Temp and volume are constant Ex Tire will burst

22. Charles’s law States that the volume of a gas is directly proportional to its temperature in Kelvins if the pressure and the number of particles is of the gas are constant. V 1 = V 2 T 1 T 2

23. Boyle’s Law Boyle’s law states that the volume of a gas is inversely proportional to its pressure if the temperature and the number of particles are constant P 1 V 1 = P 2 V 2

24. Combined Gas Law The relationship described by Boyle’s Law and Charles’s Law can be described by a single law called the combined gas law. P 1 V 1 = P 2 V 2 T 1 T 2

25. Math Problems Practice Page 80 number 1, 2 and 3

26. Beaker Breaker 2 liters of hydrogen gas are stored at a pressure of 100kPa. If the temperature does not change, what will the volume of the gas be when the pressure is decreased to 25kPa? Show your work by using the gas laws we learned yesterday

27. 3-3 Phase Changes A phase change is the reversible physical change that occurs when a substance changes from one state of matter to another

28. 6 common phase changes 1.Melting 2.Freezing 3.Vaporization 4.Condensation 5.Sublimation 6.Deposition

29. Temperature and Phase changes The temperature of a substance does not change during a phase change

30. Energy and Phase Changes Energy is either absorbed or released during a phase change During an endothermic change, the system absorbs energy from its surroundings. Heat of fusion is the energy a substance must absorb in order to change from a solid to a liquid During an exothermic change, the system releases energy to its surroundings

31. Melting and Freezing The arrangement of molecules in water becomes less orderly as water melts and more orderly as water freezes Melting is completed when all the molecules have enough energy to move. Freezing is completed when all the molecules have been drawn into an orderly arrangement.

32. Vaporization and Condensation The phase change in which a substance change from a liquid to a gas is vaporization The heat of vaporization is the energy a substance must absorb in order to change from a liquid to a gas. Evaporation takes place at the surface of a liquid and occurs at temperatures below the boiling point

33. Evaporation Evaporation takes place at the surface of a liquid and occurs at temperatures below the boiling point Vapor pressure is the pressure caused by the collisions of this vapor and the walls of the container. When the vapor pressure becomes equal to the atmospheric pressure, water boils

34. Condensation Condensation is the phase change in which a substance changes from a gas or vapor to a liquid Ex: dew on grass

35. Sublimation and Deposition Sublimation is the phase change in which the substance changes from a solid to a gas Ex :Dry Ice When a gas or vapor changes directly into a solid without first changing to a liquid is called deposition Ex: Frost on windows

36. Beaker Breaker 1.Name two of the common phase changes. 2.The temperature of a substance does _______change during a phase change

37. 1. Determine the Independent Variable A. The independent variable is chosen by the experimenter. It is the condition that he/she chooses to vary (change). B. The independent variable is graphed on the x-axis (horizontal).

38. Dependent Variable A. The dependent variable depends upon the independent variable. B. The dependent variable is graphed on the y-axis(vertical).