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Page 64 Nov. 5, 2012 Focus : Chemical and Physical Properties / Changes

Page 64 Nov. 5, 2012 Focus : Chemical and Physical Properties / Changes Objective : pre-test, define physical and chemical property, physical and chemical change HW : article, data – analysis - graph due Warm-Up : Is Humpty Dumpty falling off the wall and cracking on the ground a

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Page 64 Nov. 5, 2012 Focus : Chemical and Physical Properties / Changes

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  1. Page 64Nov. 5, 2012 Focus: Chemical and Physical Properties / Changes Objective: pre-test, define physical and chemical property, physical and chemical change HW: article, data – analysis - graph due Warm-Up: • Is Humpty Dumpty falling off the wall and cracking on the ground a physical or chemical change? • Explain your answer.

  2. Pre-Assessment / Formative • Name • November 5, 2012 • Block • Title: Formative of Objectives 6.P.2.3, 6.P.3.1, 6.P.3.3 No more than 25 minutes

  3. Homework pg. 63 • Science Fair Project • Article and questions • Bring back card for My Energy Kit

  4. Physical versus Chemical Properties

  5. Reviewing MATTER • Matter: anything that has mass and takes up space • Mass – the amount of matter in something • Volume – the amount of space something occupies • Which of the following is matter? • A car? • A box? • You?

  6. What is a property? • Property: a characteristic of a substance that can be observed

  7. http://www.gpb.org/chemistry-physics/chemistry/201

  8. States, Boiling Point, Melting Point, and Solubility Solid Liquid Gas

  9. Defining States of Matter • States of matter are NOT defined by what they are made of. • Example: solids can be elements (gold), compounds (Salt = NaCl), or mixtures (butter) Element (Au) Compound (NaCl) Mixture (Milk, Salt, etc)

  10. Defining States of Matter • States of matter are defined by whether they hold SHAPE and VOLUME Element (Au) Compound (NaCl) Mixture (Milk, Salt, etc) ALL KEEP THE SAME SHAPE AND VOLUME = Solids

  11. Defining States of Matter • Solids – have a definite SHAPE and VOLUME. Element (Au) Compound (NaCl) Mixture (Milk, Salt, etc) ALL KEEP THE SAME SHAPE AND VOLUME

  12. Particle View of a Solid • Particles in a solid are PACKED CLOSELY together and they are in a FIXED POSITION. Particles vibrate in place

  13. Liquids • Liquids – has definite VOLUME but no defined SHAPE 100 ml

  14. Particle View of a Liquid • Packed CLOSELY (like a solid), but move FREELY around each other (must stay in contact).

  15. Gases • Gases - do NOT have definite SHAPE or VOLUME. Bromine gas fills up the entire volume of the container

  16. Particle view of a Gas • Particles can MOVE FREELY and will either fill up or squeeze into available space.

  17. Changes in States of Matter • Thermal Energy – heat energy. • More thermal energy = More particle movement

  18. Changing States Increase Thermal Energy (Heat up) Solid Gas Liquid Decrease Thermal Energy (Cool off)

  19. Melting point • Melting - change from solid to liquid • Melting point - SPECIFIC temperature when melting occurs. • Each pure substance has a SPECIFIC melting point. • Examples: • M.P. of Water = 0°C (32°F) • M.P. of Nitrogen = -209.9 °C (-345.81998 °F) • M.P. of Silver = 961.93 °C (1763.474 °F) • M.P. of Carbon = 3500.0 °C (6332.0 °F)

  20. Melting Point • Particles of a solid vibrate so fast that they break free from their fixed positions. Increasing Thermal Energy Solid Liquid Melting point

  21. Vaporization • Vaporization – change from liquid to gas • Vaporization happens when particles in a liquid gain enough energy to form a gas. Increasing Thermal Energy Gas Liquid Boiling point

  22. Two Kinds of Vaporization • Evaporation – vaporization that takes place only on the surface of the liquid • Boiling – when a liquid changes to a gas BELOW its surface as well as above.

  23. Boiling Point • Boiling Point – temperature at which a liquid boils • Each pure substance has a SPECIFIC boiling point. • Examples: • B.P. of Water = 100°C (212°F) • B.P. of Nitrogen = -195.79 °C (-320.42 °F) • B.P. of Silver = 2162 °C (3924 °F) • B.P. of Carbon = 4027 °C (7281 °F)

  24. Boiling Point and Melting Point Boiling point Melting point

  25. Solubility • Maximum amount of a substance that can be dissolved in a liquid (at a specific temperature). Water (H20) at 20°C Salt (NaCl)

  26. Solubility • Solute – substance being dissolved • Solvent – liquid substance that solute is dissolved into Water (H20) at 20°C Salt (NaCl)

  27. Solubility Salt • Solute – ?????? • Solvent – ????? Water Water (H20) at 20°C Salt (NaCl)

  28. Solubility can change • Increased Temp = Increased Solubility • Different substances have different solubility curves

  29. Physical Property Physical property: a property that can be observed without changing the identity of the substance. • Examples: • luster • malleability: the ability to be hammered into a thin sheet • ductility: the ability to be stretched into a wire • melting point • boiling point • density • solubility • specific heat

  30. Special Physical Properties • Melting point: the temperature at which a substance changes from a solid to a liquid at a given pressure water = 0oC • Boiling point: the temperature at which a substance changes from a liquid to a gas at a given pressure water = 100oC

  31. Chemical Properties • Chemical property: a property that can only be observed by changing the identity of the substance • Examples: • flammability • ability to rust • reactivity with vinegar

  32. Chemical Properties & Physical and Chemical Changes

  33. Physical changes are those changes that do not result in the production of a new substance.  If you melt a block of ice, you still have H2O at the end of the change.   

  34. If you break a bottle, you still have glass.  Painting your nails will not stop them from being fingernails.  Some common examples of physical changes are: melting, freezing, condensing, breaking, crushing, cutting, and bending.

  35. Some, but not all physical changes can be reversed. You could refreeze the water into ice, but you cannot put your hair back together if you don’t like your haircut!

  36. Special types of physical changes where any object changes state, such as when water freezes or evaporates, are sometimes called change of state operations.

  37. CHEMICAL PROPERTIES Chemical properties can ONLY be observed AS the substances are changing into different substances.

  38. Chemical changes, or chemical reactions, are changes that result in the production of another substance. 

  39. FLAMMABILITY: A material’s ability to BURN in the presence of OXYGEN

  40. REACTIVITY:How readily (easily) a substance combines chemically with other substances.

  41. When you burn a log in a fireplace, you are carrying out a chemical reaction that releases carbon.  When you light your Bunsen burner in lab, you are carrying out a chemical reaction that produces water and carbon dioxide. 

  42. Common examples of chemical changes that you may be somewhat familiar with are; digestion, respiration, photosynthesis, burning, and decomposition. 

  43. Physical or Chemical Change? • Painting Wood • PHYSICAL

  44. Physical or Chemical Change? • Burning Paper • CHEMICAL

  45. Physical or Chemical Change? • Digestion of food • CHEMICAL

  46. Physical or Chemical Change? • Sugar dissolving in water • PHYSICAL

  47. Physical or Chemical Change? • Iron turning red when heated • PHYSICAL

  48. Physical or Chemical Change? • Evaporation • PHYSICAL

  49. Physical or Chemical Change? • A pond freezing in winter • PHYSICAL

  50. Physical or Chemical Change? • Melting ice • PHYSICAL

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