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MATTER AND ENERGY

MATTER AND ENERGY.

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MATTER AND ENERGY

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  1. MATTER AND ENERGY Dark matter, matter we cannot see. Perhaps it doesn’t have or emit light. Scient..ists look at galaxy clusters and determine the amount of gravity holding the cluster together. From this information they can determine mass. They find there is a great deal more mass than they can account for from the visible material, thus the proposed existence of a “new” kind of matter, dark matter..

  2. MATTER PART I CLASSIFYING MATTER

  3. Matter is anything having mass and volume. The Study of matter and how it changes is Mass- the amount of matter in an object CHEMISTRY • Mass is measured with a balance, unit is grams • mass is related to weight but isn’t the same thing. • weight is dependent upon gravity. • mass never changes Volume- anything that takes up space, unit L, cm3, mL

  4. IS AIR MATTER? Does air have mass? YES, to both, so air is matter Does air have volume?

  5. What caffeine is made of… What caffeine is like… PROPERTIES OF MATTER Composition- what matter is made of. Water is made of hydrogen and oxygen (H2O), tea has caffeine Properties-what matter is like. For example, water can dissolve many substances and caffeine is a stimulant.

  6. Intensive properties UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: What are the differences between physical and chemical properties? Extensive properties Depends on the amount of matter present Volume, mass, amount of energy in a substance Does not depend on amount of matter present Melting point, boiling point, density, ability to conduct electricity and transfer energy as heat

  7. Chemical changes UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: What are the differences between physical and chemical properties? Physical changes Change that does not change the identity or chemical makeup of the substance Cutting, melting, drawing into wire, crushing, temperature and pressure changes Substance changes into new substance b/c chemical bonds have been broken or made Occurs on molecular level Noticed by temperature change, smell/odor, bubbles (gas), rust formation Reactants products

  8. THE BASIC UNIT OF MATTER IS AN ATOM There are over 118 varieties of atoms PERIODIC TABLE http://www.webelements.com/scandium/

  9. ELEMENTScontain only one type of atom. Ex: hydrogen (H) is an element that contains only hydrogen atoms, carbon (C) contains only carbon atoms, oxygen (O) contains only oxygen atoms, etc. Atoms of elements can combine together to form compounds. COMPOUNDS are neutral groups of atoms held together by chemical bonds. Ex: CO2, H2O, H2, O2

  10. mixture pure substance HOW DO WE CLASSIFY MATTER? Alloy rims/ mixture of two metals All matter is classified as either a pure substance or a mixture Pure gold/Pure substance 24 karat 18 karat End of introductory material. Return to index

  11. CLASSIFYING MATTER Pure substance-a type of matter where all samples, no matter how big or small, have the same properties…they behave in exactly the same way. • Elements • Compounds Elements contain one type of atom, thus they CANNOT be broken down into simpler substances by chemical means. • Elements consist of either: • single atoms, such as Carbon (C), or Sodium (Na) • groups of atoms of the same type (molecules), such as H2, O2, Br2, etc.

  12. ELEMENTS MONATOMIC ELEMENTS DIATOMIC ELEMENTS ALLOTROPES Atomic nitrogen N Molecular nitrogen N2 Ozone O3 Atomic hydrogen H Molecular hydrogen H2 Graphite, buckyball Atomic oxygen O Molecular oxygen O2 Carbon C ALLOTROPE-different forms of an element in same physical state

  13. COMPOUNDS Compounds are substances made up of 2 or more different elements that are chemically combined. CO2, H2O, HCl, Na2SO4 COMPOUNDS CAN BE BROKEN DOWN INTO SIMPLER SUBSTANCES BY CHEMICAL MEANS ONLY. COMPOUNDS HAVE DIFFERENT PROPERTIES THAN THE ELEMENTS THAT MAKE THEM UP. Click on the links below to watch videos of compounds broken down into the substances that make them up. • Example-hydrolysis of water: 2H2O  2H2 + O2 • water breaks down into the hydrogen and oxygen gas which make it up. • http://www.all-science-fair-projects.com/science_fair_projects/38/819/5db524216341764c1438c1f760fddff8.html • http://earth2tech.com/2008/07/31/mit-solar-energy-storage-breakthrough/ • Example-dehydration of sugar: C12H11O22 12C(s) + 11 H2O(g) • Sugar breaks down into carbon and water

  14. Sodium, Na, is a soft, shiny metal that can be cut with a butter knife. When in contact with moisture it will “explode”. Chlorine gas, Cl2, which is a green, poisonous gas once used as a chemical weapon in military operations. ELEMENTS TO COMPOUND COMBINED WITH… Will Form…

  15. TABLE SALT! Sodium metal and chlorine gas, under the right conditions, undergo a chemical change and combine to become….. 2 Na(s) + Cl2(g) 2 NaCl The final compound has properties different from the elements that formed it.

  16. REVIEW • We are studying CHEMISTRY, the study of ________and how it ________. • Matter is anything that has___ and takes up ___. • ___ are the basic building blocks of matter. • Matter can be classified as either a ___ or a ___. • Substances are either ___ or ___. Answers: 1. matter, changes 2. mass, space 3. atoms 4. pure substance, mixture 5. elements, compounds Return to index

  17. PURE SUBSTANCE MIXTURE ? ELEMENT COMPOUND Carbon (C) H2O THUS FAR WE HAVE REVIEWED MATTER AS PURE SUBSTANCES. NOW LETS DISCOVER MATTER AS MIXTURES MATTER

  18. MATTER AS MIXTURES Mixtures are combinations of 2 or more substances where each substance retains its individual properties. HOW ARE MIXTURES LIKE COMPOUNDS? THEY ARE MADE FROM TWO OR MORE SUBSTANCES HOW ARE MIXTURES DIFFERENT FROM COMPOUNDS? MIXTURES DO NOT FORM CHEMICAL BONDS.

  19. Classifying mixtures There are two types of mixtures: 1) HOMOGENEOUS 2) HETEROGENEOUS

  20. one phase • uniformly mixed • won’t settle out • small particles …a mixture that is the same throughout. A homogeneous mixture has a composition and properties that are identical regardless of the sample is Ways to identify a homogeneous mixture: HOMOGENEOUS A SOLUTION is another name for a homogeneous mixture

  21. not uniformly mixed • more than one phase • will settle out • larger particles is … a mixture that is visibly different throughout. Heterogenous mixtures have a composition and properties that differ in any given sample. Ways to identify a homogeneous mixture: HETEROGENEOUS

  22. HETEROGENEOUS MIXTURES There are special types of heterogeneous mixtures: • Suspensions-appear uniform when mixed but settle out. • Chocolate Quik • Muddy water • Pulpy oj • Oil & Vinegar dressing • Colloids-appear uniform but they do not settle out. However, their particles are too large to be classified as a homogeneous solution. • Gelatin • Milk • Smoke • Fog • mayonnaise

  23. TYNDALL EFFECT Colloids are evenly mixed, but their particles are too large to be considered homogeneous mixtures, which are also the same throughout. Colloids show the Tyndall Effect. The Tyndall effect is the scattering of light as a beam passes through a colloid. In each picture, the colloid on the left scatters the beam making it visible

  24. MixturesSummary

  25. Practice Problems • Tossed salad • Salt water • Kool-aid • Muddy water • OJ with pulp Determine whether each is a heterogeneous or homogeneous mixture: 6. Tea 7. Banana nut bread 8. Pizza 9. Blood 10. Brass Answers: 1. He 2. Ho 3. Ho 4. He 5. He 6. Ho 7. He 8. He 9. He 10. Ho Return to index

  26. Pure Substances Made of either elements or compounds that are chemically bonded. Cannot be separated by physical means. When combined they take on new properties different from the original elements. Examples: Glucose: C6H12O6 Table Salt: NaCl Oxygen Gas: O2 Carbon Dioxide CO2 Mixtures: Two or more substances mixed together but not chemically combined. Tea = Crushed Leaf + H2O Rocks = minerals + sediments + organic matter Sugar Water = Sugar + H2O Each component retains its own identity; it does not change into something else. Can be separated by physical means Examples: Sweet tea Trail mix Air (O2, N2, CO2, Ar) Now, lets put it all together and determine how to tell substances (compounds and elements) from mixtures.

  27. oxygen atoms hydrogen atoms hydrogen atoms Elements, Compounds, and Mixtures • Two types of atoms evenly mixed • Two types of atoms chemically combined • One type of atom • Two types of atoms mixed • An element • A solution • A compound • A mixture Two of the descriptions to the right apply to each bottle below. Determine the appropriate descriptions. d & h b & g c & e a & f 1_______ 2_______ 3_______ 4_______ Return to Index Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 68

  28. Classifying Matter Review: How matter is classified Matter Pure Substances Mixtures Homogeneous Heterogeneous Elements Compounds Rocky Road ice cream, muddy water Tea, kool-aid He, O H2O, NaCl

  29. Gatorade Homogenous mixture Fruit Loops Heterogeneous mixture Pure substance Gasoline Heterogeneous mixture Dirt Sugar Crystals Pure Substance Air Homogeneous mixture Granite Heterogeneous mixture More review Classify the following substances as:Pure substance, heterogeneous mixture, or homogeneous mixture Return to index

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