Unit 2: Nature of Matter and Kinetic Theory

1. Unit 2: Nature of Matter and Kinetic Theory

2. Part 1: The Nature of Matter

3. How do we classify matter? • structure = composition • what matter is made of • how matter is organized. properties= characteristics and behavior of matter (includes changes that matter undergoes). What color is it? Is it solid, liquid or gas Is it reactive?

4. Examples of physical properties : • solubility, - dissolves in water? • melting point, boiling point • color, • density, • electrical conductivity, • physical state (solid, liquid, or gas).

5. physical change - change in matter that does not involve a change in the chemical identity • Change of state is a physical change:

6. Classifying Matter Classify by purity Is it a pure substance or mixture? Pure substance = sample of matterthat has definite chemical and physical properties, can be either an element or a compound

8. Element or Compound? compound = pure substance that can be broken down into simpler substances. salt element = substance that cannot be broken down into simpler substances. gold

9. Compounds Are More Than One Element formula = combination of the chemical symbols that show what elements make up a compound and the number of atoms of each element

10. silver + bromine = silver bromide Compounds Are More Than One Element ****The properties of the compound are different from the properties of the elements that compose the compound.

11. Pure Substance or Mixture? Mixture = made up of different kinds of matter the basic identity of each substance is not changed = no fixed composition

12. Pure substance or a mixture? • Homogeneous mixtures are the same throughout. • Also known as a solution.

13. When you dissolve sugar in water, sugar is the solute—the substance being dissolved. • The substance that dissolves the soluteis the solvent. in this case it is water • solute + solvent = solution • When the solvent is water, the solution is called an aqueous solution.

14. Pure Substance or Mixture? heterogeneous mixture is one with different compositions, depending upon where you look

16. Matter Mixture Pure Substance homogenous element heterogeneous compound

17. a substance must be separated chemically • a mixture can be separated physically

18. An example of a pure substance in everyday life is _____. • pond water • b. a cola drink • sugar • d. concrete c. sugar

19. A soft drink is an example of a(n) _____. • compound • heterogeneous mixture • element • homogeneous mixture d. homogenous mixture

20. Identify each of the following as either a compound or a mixture. mixture A. sand B. water compound C. juice mixture

21. In ocean water, salt is a(n) _____. • alloy • b. solution • c. solute • d. solvent c. solute

22. pure substance? element or compound?a mixture? Heterogeneous or homogenous Aluminum foil Pure substance, element

23. pure substance? element or compound?a mixture? Heterogeneous or homogenous • bowl of cereal mixture, heterogeneous

24. pure substance? element or compound?a mixture? Heterogeneous or homogenous • whipped cream Mixture, homogenous

25. pure substance? element or compound?a mixture? Heterogeneous or homogenous • oil and vinegar dressing Mixture, heterogeneous

26. pure substance? element or compound?a mixture? Heterogeneous or homogenous • aspirin - acetylsalicylic acid Pure substance, compound

27. pure substance? element or compound?a mixture? Heterogeneous or homogenous • orange juice with pulp Mixture, heterogeneous

28. pure substance? element or compound?a mixture? Heterogeneous or homogenous • gold Pure substance, element

29. pure substance? element or compound?a mixture? Heterogeneous or homogenous • salt Pure substance, compound

30. pure substance? element or compound?a mixture? Heterogeneous or homogenous • peanut butter Mixture, homogenous

31. Chemical Properties • Chemical properties are those that can be observed only when there is a change in the composition of the substance. • Rusting is a chemical reaction in which iron combines with oxygen to form a new substance, iron oxide. • Examples of chemical property: • flammability • reactivity

32. A chemical property always relates to a chemical change - the change of one or more substances into other substances. Chemical Changes chemical change = chemical reaction.

33. Clues that a chemical change has occurred:

34. Below are listed changes that can be observed in everyday life. Tell whether it is a physical change or a chemical change. • an icicle melting • charcoal burning • magnetizing a piece of steel • iron rusting • rubbing alcohol evaporating from the skin physical change chemical change physical change chemical change physical change

35. Chemical Reactions chemical change involves only a rearrangement of the atoms. Atoms DO NOT just appear or disappear. ******Law of Conservation of Mass****** In a chemical change, matter is neither created nor destroyed.

36. Chemical Reactions and Energy • All chemical changes also involve some sort of energy change. • Energy is either taken in or given off as the chemical change takes place. Energy is the capacity to do work. • Work is done whenever something is moved.

37. Chemical Reactions and Energy • Energy is also produced and released in the form of heat and light. Chemical reactions that GIVE OFF heat energy are called exothermic reactions.

38. Chemical Reactions and Energy • Chemical reactions that ABSORB heat energy are called endothermic reactions.

39. Classify each of the following as a chemical or physical property. physical property A. density B. reactivity chemical property physical property C. color physical property D. melting point

40. Part 2: The Kinetic Theory • States of Matter • solid • liquid • gas • plasma

41. Intermolecular Forces (IMF) • Attractive forces between molecules. • Much weaker than chemical bonds within molecules.

42. The Kinetic Theory of Matter 1. Matter is composed of PARTICLES. 2. Particle movement is rapid, constant, and random (Brownian motion)

43. The Kinetic Theory of Matter 3.All collisions are perfectly ELASTIC (NO energy lost).

44. Kinetic theory of matter Kinetic energy (K.E.) = energy of motion • gases have the least restriction on motion • have the most K.E. • solids have the most restriction on motion • have the least K.E.

45. Kinetic model of gases • Gases: matter with variable shape and variable volume • Gas particles move in a straight line until they collide with container or each other

46. Kinetic model of liquids • Liquids: matter with variable shape and definite volume • Particles slide past each other but are so close together they do not move in a straight line

47. Kinetic model of solids • solids: matter with definite shape and definite volume • Particles cannot move past each other, they are in constant motion bouncing off neighbors

48. Other forms of matter • Plasmas - gaseous mixture of ions -exists at high temperatures • most common form of matter in the universe but least common on Earth itself

49. Plasmas continued • an ionized gas that conducts electricity -forms at very high temps when matter absorbs energy and breaks apart • The sun is made of plasma - also found in fluorescent lights

50. Temperature and kinetic energy • temperature—the measure of the average K.E. of particles in a sample • Kelvin (K) – SI base unit of temperature; measures average K.E.