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Matter and Change

Matter and Change. Chapter 3. Diatomic. Two atoms of the same element bonded together. Phase. A sample of matter that looks the same. Substance . A form of matter that has a uniform and unchanging composition…aka a pure substance. The 3 Physical States of Matter. Solid Liquid Gas.

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Matter and Change

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  1. Matter and Change Chapter 3

  2. Diatomic • Two atoms of the same element bonded together

  3. Phase • A sample of matter that looks the same

  4. Substance • A form of matter that has a uniform and unchanging composition…aka a pure substance

  5. The 3 Physical States of Matter • Solid • Liquid • Gas

  6. Solid • Definite shape and volume • Atoms/molecules held rigidly in place • Non-compressible

  7. Liquid • No definite shape; takes the shape of its container; Non-compressible • Definite volume • Molecules are farther apart than those of a solid, allowing molecules to flow past one another

  8. Gas • No definite shape nor volume • Gases take the shape & volume of their container • Gases are mostly empty space • Compressible

  9. What is the physical state of each of the following at room temperature? • gold • gasoline • helium • bromine • lithium • nitrogen

  10. The 3 Chemical Classes of Matter • Element • Compound • Mixture

  11. 1. Element • A substance that can’t be reduced to a simpler form • The building blocks of all substances • Made up of only one type of atom

  12. 3 Types of Elements • Metals: to the left of the “stair-step;” the majority of the elements • Non-metals: to the right of the “stair-step” • Metalloids: non-metals on the stair step having metal and non-metal properties

  13. 2. COMPOUNDS • formed when 2 or more different elements join chemically in a definite pattern/ arrangement • Can be made or separated by chemical reactions

  14. 2 Types of Compounds • ionic compounds: made up of a metal and a non-metal portion • covalent compounds: composed of non-metals

  15. Which of these are elements and which of these are compounds? • Hg • NaCl • O2 • H2O • S8

  16. 3. Mixtures • 2 or more distinct substances mixed together with variable composition • may have distinct phases • can be separated by physical methods • Distillation • Filtration • chromotography

  17. 2 Types of Mixtures • Homogeneous • Heterogeneous

  18. Homogeneous Mixture: aka Solution (sol’n) • Has a constant composition throughout • always has a single phase • can be any state of matter

  19. Give me some examples of solutions in each of the 3 states of matter. gas: Air nitrous oxide(dentist) liquid: salt water 7-up solid: gold ring, metal alloys

  20. Heterogeneous Mixture • A mixture that does not blend smoothly throughout • 2 or more distinct phases are visible

  21. What are some examples of a heterogeneous mixture?

  22. Which of the 3 are substances? • Elements • Compounds • Mixtures

  23. Classify each of the following as elements, compounds, or mixtures. • Silver • pine tree • Carbon dioxide • orange juice • oxygen • iced tea • air • water

  24. Separating Mixtures • Filtration • Distillation • Crystallization • Chromatography

  25. 1. Filtration • Filtration: a technique that uses a porous barrier to separate a solid from a liquid. • Separates heterogeneous mixtures of solids and liquids

  26. Filtration

  27. 2. Distillation • A separation technique that is based on differences in the boiling points of the substances involved • A mixture is heated until the substance with the lowest boiling point boils to a vapor that can then be condensed into a liquid and collected.

  28. Distillation

  29. 3. Crystallization • A separation technique that results in the formation of pure solid particles of a substance from a solution containing the dissolved substance. • ie. Rock candy

  30. Crystallization

  31. 4. Chromatography • A technique that separates the components of a mixture based on the tendency of each to travel across the surface of another material.

  32. Chromatography

  33. Physical Properties of Matter • Physical properties are characteristics that can be observed or measured without changing the sample’s composition • intensive properties: are independent of sample size. • ie. density, color, boiling point • extensive properties are dependent on the amount of material present. • ie. mass and volume

  34. Physical Changes of Matter • Changes that alter a substance without changing its chemical composition • ie. Changes in physical state

  35. Sublimation: solid to gas phase For example: Dry ice

  36. Boiling: liquid to gas

  37. How can you change the physical appearance without changing the state

  38. Chemical Properties of Matter • Chemical properties are only observed in chemical reactions • Reactivity: the tendency of a substance to undergo a particular chemical reaction when exposed to an agent.

  39. Examples • 2H2O reactivity to electric current→ 2H2(g) + O2(g) • H2O reactivity to alkali metals→ H2(g) [Cesium in water causes explosion] • Fe reactivity to O2 + H2O (fog)→ Fe2O3(rust) Iron Oxide (you leave your bike out in the fog and it rusts)

  40. Rubidium,Cesium, & Francium in water • http://www.youtube.com/watch?v=jJGqC4vXBms

  41. Chemical Change • A process that involves one or more substances changing into new substances

  42. Reactants: the starting materials in a chemical reaction • Products:the newly formed substances from a chemical reaction

  43. 4 Indicators of Chemical Change: (often accompany chemical change) • color change • precipitate formation • gas evolution • heat evolution or heat absorption

  44. 2 Types of Reactions • Exothermic: Heat is released/given off during a chemical reaction • Endothermic: Heat is absorbed during the chemical reaction

  45. DEMOS: Examples of Chemical Change

  46. Gas Formation • Zn + 2 HCl → H2 (g) + ZnCl2

  47. Color Change and Precipitate Formation • 2 KI + Pb(NO3)2→ 2 KNO3 + PbI2 (s) • http://www.youtube.com/watch?v=RE-dFN7U91M&feature=player_detailpage

  48. Conservation of Mass • In a chemical reaction, matter is neither created nor destroyed, but it can change from one form to another. • Mass of Reactants= Mass of Products • → Material Balance

  49. Conservation of Mass • From a lab experiment designed to separate water into hydrogen and oxygen, a student collected 10.0 g of hydrogen and 79.4 g of oxygen. How many grams of water were originally present?

  50. Chemistry • is the study of the composition of substances and the changes they undergo. • In chemistry, a specific language is used when referring to elements.

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