Pure Substances Mixtures States of Matter Physical and Chemical Changes

1. Matter and Change Pure Substances Mixtures States of Matter Physical and Chemical Changes

2. Everything that has mass and volume is called matter. What is matter?

3. Sort your matter! • Cards have the name of a specific kind of matter on the front and what it’s made of on the back • Group your cards according to similarities in the ingredients of each kind of matter

4. Substances - One Ingredient Characteristics Include • A substance is matter of a particular kind • Fixed composition • Cannot be separated into simpler substances by physical methods (physical changes) • Properties do not vary

5. More specifically… • Substances can be broken down into two groups • Divide your substance group into two groups

6. What are "substances"? Substances can be identified as either an element or compound

7. Compounds (made up of molecules) Can be decomposed into simpler substances by chemical changes always in a definite ratio Elements (made up of individual atoms) Cannot be decomposed into simpler substances by chemical changes What is a pure substance?

8. Pictures of atoms and molecules

9. What is a mixture? Mixtures are two or more substances that are NOT chemically combined. They are mixed

10. Characteristics of Mixtures • Components (parts of the mixture) retain their characteristic properties (red color is still red color when mixed) • May be separated into pure substances by physical methods

11. 2 types of mixtures • Take your remaining cards and group them into two groups based on their compositions.

12. Heterogenous Mixtures • Do not have same composition throughout • Components are distinguishable • Can be separated by physical means Examples: fruit salad, vegetable soup, glass of ice water, etc.

13. Phases in Heterogeneous Mixture • Phases are the individual substances that are combined to make up the mixture. • Can include different states of matter of the same material, ex. Ice & water • Phase Boundary/Interface – where two phases touch

14. Homogenous Mixtures • Have the same composition throughout • Components are indistinguishable (Look the same throughout ) • can be separated by physical means (distillation, centrifuge, gravimetric filtering, etc.).

15. Homogenous Mixtures • Examples: salt water, solutions, Kool-Aid • Also called solutions

16. What are solutions? Solutions are homogenous mixtures They are easily separated by distillation or evaporation. Examples: sugar water, salt water

17. Solutions • Solute – substance being dissolved • Solvent – substance doing the dissolving. Usually water. • Concentrated – high solute to solvent ratio • Dilute – Low solute to solvent ratio • Precipitate – solid that forms from two solutions.

19. Solubility – How much solute will dissolve in a certain amount of solvent. See Fig 3.7 • Unsaturated – more can be dissolved • Saturated – no more will dissolve • Supersaturated – more than should be dissolved at that temperature is dissolved in the solution. Very unstable and will precipitate easily

20. What are colloids? Colloids are solutions. They can be described as a substance trapped inside another substance. They can be identified by their characteristic scattering of light. For example: air trapped inside the fat molecules in whipped cream.

21. States of Matter • Solids • Liquids • Gases • Plasma • Others

22. Solids, Liquids, Gases

23. Solids • Have a definite shape • Have a definite volume particles are packed tightly together • Almost incompressible • Expand only slightly when heated

24. Liquids • Can flow • Takes the shape of its container • Has a fixed volume • Almost incompressible • Expand when heated

25. Gases • Particles are far apart • Take the shape and size of their container • Expand to fill any space • Are easily compressed

26. What is the difference between a gas and a vapor? • The term gas is used for substances that are in a gaseous state at room temperature. • The term vapor is used for describing the gaseous state of a substance that is usually a solid or liquid at room temperature.

28. Physical properties? • Physical properties are those that we can determine without changing the identity of the substance we are studying.

29. Melting point Boiling point Vapor pressure Color State of matter Density Electrical conductivity Solubility Adsorption to a surface Hardness Physical properties

30. Chemical properties? • Chemical properties describe the way a substance can change or react to form other substances.

31. Comparison of Physical and Chemical Properties

32. Intensive and Extensive Properties • Physical and chemical properties may be intensive or extensive.

33. What are intensive properties? • Intensive properties such as density, color, and boiling point do not depend on the size of the sample of matter and can be used to identify substances.

34. What are extensive properties? • Extensive properties such as mass and volume do depend on the quantity of the sample.

35. What is a physical change? • When the substance changes state but does not change its chemical composition.

36. Melting Boiling Freezing Condensing Dissolving Cutting Examples of Physical Changes

37. What are chemical changes? • A chemical change occurs when a substance changes into something new. • A new substance has new properties

38. Reaction with acids Reaction with bases (alkalis) Reaction with oxygen (combustion) Ability to act as oxidizing agent Ability to act as reducing agent Reaction with other elements Decomposition into simpler substances Corrosion Examples of Chemical Changes

39. Signs of a Chemical Change • Formation of a gas - bubbles • Color change • Precipitate formed • Change in heat – hot or cold (not always definitive) • Physical properties of substance change (no longer soluble, texture changes, etc.)

40. Law of Conservation of Matter There is no observable change in the quantity of matter during a chemical reaction or a physical change. In other words, matter cannot be created nor destroyed. It is just converted from one form to another

42. On earth we live upon an island of "ordinary" matter. The different states of matter generally found on earth are solid, liquid, and gas. We have learned to work, play, and rest using these familiar states of matter. Sir William Crookes, an English physicist, identified a fourth state of matter, now called plasma, in 1879.

43. Plasma temperatures and densities range from relatively cool and tenuous (like aurora) to very hot and dense (like the central core of a star). Ordinary solids, liquids, and gases are both electrically neutral and too cool or dense to be in a plasma state. The word "PLASMA" was first applied to ionized gas by Dr. Irving Langmuir, an American chemist and physicist, in 1929.

44. Star formation in the Eagle NebulaSpace Telescope Science Institute, NASA (below) (Above) X-ray view of Sun from Yohkoh, ISAS and NASA

45. Plasma radiation within the Princeton Tokamak during operation.

46. Laser plasma interaction during inertial confinement fusion test at the University of Rochester.

47. Both inertial and magnetic confinement fusion research have focused on confinement and heating processes with dramatic results. The next stage of operating power reactors will produce about 1 GW of power and operate at 120 million degrees Kelvin.

48. Plasma can be accelerated and steered by electric and magnetic fields which allows it to be controlled and applied. Plasma research is yielding a greater understanding of the universe. It also provides many practical uses: new manufacturing techniques, consumer products, and the prospect of abundant energy.

49. Products manufacturedusing plasmas impact our daily lives:

50. EXAMPLES: • Computer chips and integrated circuits • Computer hard drives • Electronics • Machine tools • Medical implants and prosthetics • Audio and video tapes • Aircraft and automobile engine parts • Printing on plastic food containers • Energy-efficient window coatings • High-efficiency window coatings • Safe drinking water • Voice and data communications components • Anti-scratch and anti-glare coatings on eyeglasses and other optics