2. Chemistry I Honors Chapter 1 “Chemistry and You” SAVE PAPER AND INK!!! If you print out the notes on PowerPoint, print "Handouts" instead of "Slides“ in the print setup. Also, turn off the backgrounds (Tools>Options>Print>UNcheck "Background Printing")!

3. Welcome to the World of Chemistry!!

4. Why study Chemistry? Explain the natural world –Why? Prepare for a career –Directly- in a lab –Indirectly- problem solving and thinking skills Be an informed citizen –Vote –Don’t get scammed

5. The Nature of Matter Chemists are interested in the nature of matter and how this is related to its atoms and molecules. Gold Mercury

6. Chemistry & Matter We can explore the MACROSCOPIC world — what we can see —We can explore the MACROSCOPIC world — what we can see — to understand the Nanoscale worlds we cannot see.to understand the Nanoscale worlds we cannot see. We write SYMBOLS to describe these worlds.We write SYMBOLS to describe these worlds.

7. A Chemist’s View of Water H 2 O (gas, liquid, solid) MacroscopicMacroscopic SymbolicSymbolic NanoscaleNanoscale

8. A Chemist’s View 2 H 2 (g) + O 2 (g) --> 2 H 2 O(g) MacroscopicMacroscopic SymbolicSymbolicNanoscaleNanoscale

9. So What is Chemistry? The study of matter, its composition, properties, and the changes it undergoes. Pure science gathers knowledge for knowledge’s sake Applied science uses chemistry to attain certain goals, in fields like medicine, agriculture, and manufacturing (Technology)

11. Branches of Chemistry Analytical Chemistry -studies composition of substances. Organic Chemistry -compounds containing carbon Inorganic Chemistry -substances without carbon Biochemistry- Chemistry of living things Physical Chemistry studies behavior of substances –rates and mechanisms of reactions –energy transfers

12. Scientific Method - orderly way to solve problems 1.State the problem. 2.Gather information. (Research) 3.Form a hypothesis. (educated guess) 4.Test the hypothesis. (Experiment & make observations) 5.Analyze the data. 6.Form a conclusion. (Hypothesis was correct, incorrect, or inconclusive) 7. Communicate the results. (Publish)

13. Observation – Something you sense or a Something you sense or a measurement you make. FACTS!!! (Do this during experiment) Value Judgment – fact + opinion ( Do this before/during Conclusion) Don’t make decisions during a lab! Record the facts, just the facts!

14. Do you know the difference between the independent and dependent variables?

15. Independent Variable The independent, or manipulated variable, is a factor that is intentionally varied by the experimenter. (Placed on X (horizontal) axis of graph) Ex. John is going to use 25g., 50g., 100g., 250g., 500g. of sugar in his experiment. (the mass of sugar john decided to use each trial would be the independent variable!)

16. Dependent Variable The dependent, or responding variable, is the factor that may change as a result of changes made in the independent variable. (Placed on Y (vertical) axis of graph)

17. Independent Variable Dependent Variable Title

18. Where did it all begin? The word “atom” comes from the Greek word “atomos” which means indivisible. The idea that all matter is made up of atoms was first proposed by the Greek philosopher Democritus in the 5th century B.C.

19. Empedocles Empedocles (Greek, born in Sicily, 490 B.C.) – earth, air, fire, and water Suggested there were only four basic elements – earth, air, fire, and water. The elementary substances (atoms to us) combined in various ways to make everything. No experiments to support idea Idea of ‘atomos’ Atomos = ‘indivisible’ ‘Atom’ is derived

20. The Hellenic Market FireWaterEarth Air ~ ~

21. Alchemy True ancestor of chemistry Goals: Changing cheap metals into gold Find the “Elixir of Life” a universal cure for disease, and a way of prolonging life. Alchemists were not successful, however…

22. The Alchemist Frankly, I’d be satisfied if I could turn gold into lead!

23. Important Contributions a) lab techniques & tools –Distillation – separates the parts of a solution – based on differences in boiling point temperatures b) alloys – solutions of metals –brass, bronze, solder, pewter, sterling silver, etc.

24. During the Renaissance Period (15 th – 16 th centuries) alchemy made the change to “Chemistry”! They began to question the old beliefs, but it wasn’t until the 1770’s that the first experiments were done to disprove Empedocles’ idea of “Four Basic Principles”

25. What is Matter? Matter is anything that has mass and takes up space. Mass is the amount of matter an object contains. Is Air matter? What are the two criteria for matter? Does it take up space? Does it have mass?

26. All matter has the property of inertia Inertia is the resistance of matter to a change of direction or rate of motion.

27. What is NOT Matter? Energy! All matter is affected by energyAll matter is affected by energy Energy is the ability to do work or cause change. Potential Energy – stored (in bonds between atoms or by position) Kinetic Energy – doing work or causing change Activation Energy is often needed to change potential energy to kinetic energy.

28. Types of Energies Mechanical Chemical (stored in chemical bonds) Heat (thermal) Nuclear Light (radiant) Electrical Sound

29. All chemical reactions involve energy changes energy is either absorbed or liberated!. Energy can change forms! Conservation of Energy Energy can be neither created or destroyed in ordinary changes (not nuclear), it can only change form.Energy can be neither created or destroyed in ordinary changes (not nuclear), it can only change form. Its not just a good idea, its the law.Its not just a good idea, its the law.

30. MATTER Can it be physically separated? Homogeneous Mixture (solution) Heterogeneous Mixture CompoundElement MIXTURE PURE SUBSTANCE yesno Can it be chemically decomposed? noyes Is the composition uniform? noyes ColloidsSuspensions Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem Matter Flowchart

31. A substance has a definite, unvarying composition – contains only one type of matter it contains only one type of matter - either an element or a compound water, ammonia, sucrose, gold, oxygen

32. ELEMENTS Elements - pure substances that cannot be decomposed by ordinary means into other substances.Elements - pure substances that cannot be decomposed by ordinary means into other substances. SodiumBromine Aluminum Only one kind of atom

33. 118 elements have been identified 82 elements occur naturally on Earth gold, aluminum, lead, oxygen, carbon 36 elements have been created by scientists technetium, americium, seaborgium 1.4 Elements have a 1 or two letter symbol, and compounds have a formula. An element’s first letter always capitalized; if there is a second letter, it is written lowercase: B, Ba, C, Ca, H, He

34. Copper atoms on silica surface. An atom is the smallest particle of an element that has the chemical properties of the element.An atom is the smallest particle of an element that has the chemical properties of the element. Distance across = 1.8 nanometer (1.8 x 10 -9 m)

35. Compounds Composed of 2 or more elements chemically combined in a fixed ratio Properties differ from those of individual elements –EX: table salt (NaCl) ammonia (NH 3 ) glucose (C 6 H 12 O 6 ) More than one kind of atom! kind of atom!

36. Sodium metal Soft, can be cut with a knife Shiny Good conductor of electricity Very reactive

37. Sodium in water

38. Chlorine gas Greenish gas Poisonous Heavier than air

39. Sodium in chlorine gas

40. Sodium chloride, NaCl Sodium chloride dissolves in water rather than reacts with water. Sodium chloride is a white solid, not a poisonous green gas. Sodium chloride is its own substance with its own properties, not those of either sodium or chlorine.

41. CHEMICAL COMPOUNDS are composed of atoms and can only be decomposed by chemical means.

42. Mixtures Blend of 2 or more substances- does NOT involve reaction or change in composition of either substance. Variable composition Homogeneous or Heterogeneous

43. 1. 1. Homogenous mixture – completely uniform throughout composition completely uniform throughout 1.4 (No lumps, bumps, chunks, or layers) Only 1 phase Also called Solutions Phase- any part of a system with uniform composition and properties uniform composition and properties

44. Heterogeneous mixture – composition is not uniform throughout. visibly separate phases (2 or more)

45. Physical means can be used to separate a mixture into its pure components. magnet 1.4 distillation FiltrationDecantingCrystallizationChromatography

46. Separation of a Mixture Distillation: takes advantage of different boiling points. NaCl boils at 1415 o C Water boils at 100 o Water boils at 100 o C

47. Filtration separates a liquid from a solid.

48. Compound vs. Mixture CompoundMixture Made of one kind of material Made of more than one kind of material Made by a chemical change Made by a physical change Definite composition Variable composition

49. Properties of Matter Physical properties - can be determined without changing the identity of the substance Physical properties can be either extensive or intensive

50. An extensive property depends upon the amount of matter present. mass length volume 1.6

51. An intensive property of a material does not depend upon how much matter is present. densityphysical state temperature malleability colorductility solubilitymelting point conductivity boiling point

52. STATES OF MATTER Solids — have rigid shape, fixed volume. IncompressibleSolids — have rigid shape, fixed volume. Incompressible Liquids — definite volume;Liquids — definite volume; take shape of container; flow; incompressible.take shape of container; flow; incompressible. Gases — No definite shape or volume - expand to fill their container; compressible; flowGases — No definite shape or volume - expand to fill their container; compressible; flow

53. States of Matter Solid Liquid Gas Definite Volume? YES NO Definite Shape? YES NO Result of a TemperatureI ncrease? Small Expans. Large Expans. Will it Compress? NO YES

56. Chemical properties describe the way a substance can change or react to form other substances. These properties, then, must be determined using a process that changes the identity of the substance of interest. In other words, we have to define chemical properties of a substance by the chemical changes it undergoes. Does it burn? Explode? React in water?

57. iron plus oxygen forms rust,iron plus oxygen forms rust, so the ability to rust is a chemical property of iron

58. Physical vs. Chemical Examples: –melting point –flammable –density –magnetic –tarnishes in air physical chemical physical chemical

59. CHANGES A physical change does not alter the composition or identity of a substance. 1.6 Ex.: CrushingCutting Phase changes Phase changes DissolvingMixing DissolvingMixing

60. A chemical change - a change in which one or more substances are converted into different substances. Alters the composition or identity of the substance(s) involved. Signs of chemical change: –Fizzing/bubbling –Smoke –Fire/Explosion –Energy given off (heat, light, sound) –Precipitate formed (insoluble solid) –Color change –Odor change http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA0/MOVIES/S1047.MOV

61. A Colorful Demonstration: The Remsen Reaction

62. Physical vs. Chemical Examples: –rusting iron –dissolving in water –burning a log –melting ice –grinding spices ChemicalPhysicalChemicalPhysicalPhysical

63. Law of conservation of mass Matter cannot be created nor destroyed in any chemical reaction. During any chemical reaction, the mass of the products is always equal to the mass of the reactants. All the mass can be accounted for: –Burning of wood results in products that appear to have less mass as ashes; where is the rest?

64. - Page 55 reactants = product 43.43 g Original mass = 43.43 g Final mass

65. Classification of Matter