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Matter – Properties and Changes

Matter – Properties and Changes. Properties of Matter Changes of Matter Mixtures of Matter Elements and Compounds. PROPERTIES OF MATTER Types of Properties. Physical Properties - properties that can be observed and measured without changing the composition

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Matter – Properties and Changes

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  1. Matter – Properties and Changes Properties of Matter Changes of Matter Mixtures of Matter Elements and Compounds

  2. PROPERTIES OF MATTERTypes of Properties Physical Properties - properties that can be observed and measured without changing the composition examples – color, texture, hardness) types of physical properties 1) intensive - do not depend upon amount of the substance 2) extensive - depend upon amount of the substance

  3. Properties- Physical • Examples: length color mass volume density phase conductivity texture

  4. Properties of Matter • chemists use characteristic properties to tell substances apart and to separate them • some properties define a group of substances

  5. Types of Properties • Physical- characteristics that can be observed or measured without changing the identity of a substance • Ex. melting point, boiling pt • Chemical- relates to a substances ability to undergo changes that transform it into a different substance • Easiest to see when a chemical is reacting

  6. Physical Changes in Matter • change in a substance that doesn’t change the identity of the substance • Ex. grinding, cutting, melting, boiling • Includes all changes of state (physical changes of a substance from one state to another)

  7. Solid • definite volume • definite shape • atoms are packed together in fixed positions • strong attractive forces between atoms • only vibrate in place

  8. Liquid • definite volume • indefinite shape • atoms are close together • atoms can overcome attractive forces to flow

  9. Gases • indefinite volume • indefinite shape • atoms move very quickly • atoms are far apart • pretty weak attractive forces

  10. Changes of State

  11. Plasma • high temperature state in which atoms lose their electrons • Ex. the sun

  12. CHANGES IN MATTERTypes of Changes 1. physical - changes in which a substance is altered without changing composition a. examples- phase changes, cut into pieces 2. chemical - changes in which one or more substances change into new substances with new properties a. reactants – substances that react b. products - substances that are produced

  13. PROPERTIES OF MATTERTypes of Properties Chemical Properties - properties relating to the ability of substances to combine with or change into other substance (has a uniform and unchanging composition) examples 1) reaction with water 2) ability to combine with oxygen 3) reaction with acids

  14. Changes Chemical • Changes that result in a new substance • a.k.a chemical reaction Word equation: hydrogen + oxygen water reactants product copper + silver nitratesilver + copper nitrate reactants product

  15. Changes Chemical Formula Equation Cu + 2AgNO3 Cu(NO3)2 + 2Ag Pb(NO3)2 + 2KI  PbI2 + 2KNO3 (be able to identify reactants and products)

  16. Chemical changes Examples of chemical changes 1) digestion of food 2) burning (combustion) 3) fermentation 4) rusting 5) tarnishing of silver

  17. CHANGES IN MATTER Evidence of Chemical Changes 1. change in color and/or appearance 2. change in energy 3. change in odor 4) formation of a precipitate or a gas

  18. Energy Changes in Matter • when any change occurs, energy is always involved • energy can be in different forms (light, heat, etc.) • energy is never destroyed or created (law of conservation of energy)

  19. Energy changes related to chemical changes (reactions) • exothermic - energy is released (given off in the form of heat or light) - burning, explosion • endothermic - energy must be continuously added to keep the reaction going - electrolysis of water or salt

  20. Energy Changes in Matter • Exothermic Reaction- reaction that gives off energy (feels warm on outside) • Endothermic Reaction- reaction that uses up energy (feels cold on outside)

  21. MIXTURES A. Definitionof Mixture - combination of pure substances that retain their properties B. Types of Mixtures 1. heterogeneous - individual substances are distinct (composition is not uniform throughout) a. examples – sand, vegetable soup 2. homogeneous - individual substances are not distinct (uniform composition throughout) a. examples - solutions

  22. MIXTURES Types – homogeneous __________________________________________________________________________________________________________ type of solution examples __________________________________________________________________________________________________________ solid – liquid sugar water, salt water ___________________________________________ gas – liquid carbonated beverages ________________________________________________________ liquid – liquid alcohol, vinegar ________________________________________________________ gas – gas air _______________________________________________________ solid - solid alloys (metal + metal) ________________________________________________________

  23. MIXTURES Separating Mixtures 1. Filtration 2. Distillation 3. Crystallization 4. Chromatography

  24. Separation Techniques • Filtration- solid part is trapped by filter paper and the liquid part runs through the paper • Vaporization- where the liquid portion is evaporated off to leave solid

  25. Separation Techniques • Decanting- when liquid is poured off after solid has settled to bottom • Centrifuge- machine that spins a sample very quickly so that components with different densities will separate

  26. Separation Techniques • Paper Chromatography- used to separate mixtures because different parts move quicker on paper than other

  27. Elements

  28. ELEMENTS AND COMPOUNDSElement-a pure substance that cannot be broken down by simple means The periodic table organizes the 91 naturally occurring elements and scientifically created elements • A. Mendeleev created the original periodic table.

  29. Periodic Table

  30. Periodic Table • two rows below the periodic table are the lanthanide and actinide series • these rows fit after #57 and #89 • they are only at the bottom to keep the width of the chart smaller

  31. Types of Elements • Metals • an element that is a good conductor of electricity • at room temperature, most are solids • malleable- can be rolled or hammered into sheets • ductile- can be made into wire • high tensile strength- can resist breakage when pulled • most have silvery or grayish white luster

  32. Types of Elements • Nonmetals • an element that is a poor conductor of heat and electricity • many are gases at room temperature • some are solids: usually brittle, not malleable

  33. Types of Elements • Metalloids • an element that has some characteristics of metals and nonmetals • appear along staricase line • B, Si, Ge, As, Sb, Te • all are solids at room temperature • less malleable that metals but less brittle than nonmetals • are semiconductors

  34. Types of Elements • Noble Gases • generally unreactive gases • in far right column of periodic table

  35. ELEMENTS AND COMPOUNDSCompounds definition - a compound is a pure substance that is the combination of two or more different elements ie: NaCl – table salt Na- combustible solid and Cl – poisonous gas examples of compounds a. sodium bicarbonate NaHCO3 b. hydrochloric acid HCl c. sulfur dioxide SO2

  36. ELEMENTS AND COMPOUNDSCompounds examples of formation of compounds from elements (synthesis reactions) a. 2 Na + Cl2 -----> 2 NaCl b. 2 H2 + O2 ------> 2 H2O c. N2 + 3H2 ------> 2NH3

  37. ELEMENTS AND COMPOUNDSCompounds examples of decomposition of compounds to form elements a. 2NaCl  2Na + Cl2 b. 2 H2O  2H2 + O2

  38. The organization of Matter

  39. PURE SUBSTANCE MIXTURE yes no yes no Is the composition uniform? Can it be decomposed by chemical means? Matter Flowchart MATTER yes no Can it be separated by physicalmeans? Homogeneous Mixture (solution) Heterogeneous Mixture Compound Element

  40. The Law Conservation of Mass States that mass can neither be created nor destroyed. Mass of reactants = mass of products 28 g of Na + 28 g of Cl = 56 g of NaCl

  41. Law of Conservation of Mass and chemical changes- Mass reactants = Mass products (mass is neither created nor destroyed in chemical reactions) Lavoisier (1743 - 1794) experiment [ 216 g of HgO --> 200 g Hg + 16g O2 ] 216 grams of mercury oxide when heated will produce 200 grams of mercury and 16 grams of oxygen

  42. Law of Definite Proportions 1.Definition - a compound is always composed of the same elements in the same proportions by mass 2. examples a. water- H2O (always has a ratio of 1 gram of hydrogen to 8 grams of oxygen) b. ammonia - NH3 (always combine in a ratio of 14 grams of nitrogen to 3 grams of hydrogen)

  43. Law of Multiple Proportions 1. definition - when different compounds are formed by a combination of the same elements, different masses of one element will combine with the same relative mass of the other element in a ratio of small whole numbers

  44. Law of Multiple Proportions WATER (H2O) 2 grams of hydrogen combine with 16 grams of oxygen PEROXIDE (H2O2) 2 grams of hydrogen combine with 32 grams of oxygen The ratio that compares the amount of oxygen in water and peroxide is 1:2

  45. Law of Multiple Proportions SULFUR DIOXIDE (SO2) 32 grams of sulfur combine with 32 grams of oxygen SULFUR TRIOXIDE (SO3) 32 grams of sulfur combine with 48 grams of oxygen The ratio that compares the amount of oxygen in sulfur dioxide and sulfur trioxide is 2:3

  46. Periodic Table • Groups • also called families • vertical columns • numbered 118 • have similar chemical properties • Periods • horizontal rows • properties changes consistently across a period

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