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Matter and Change Chapter 3. Diatomic Two atoms of the same element bonded together.

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Presentation on theme: "Matter and Change Chapter 3. Diatomic Two atoms of the same element bonded together."— Presentation transcript:

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 O 2 H 2 O S 8

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 1. Filtration 2. Distillation 3. Crystallization 4. 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 2H 2 O reactivity to electric current→ 2H 2 (g) + O 2 (g) H 2 O reactivity to alkali metals→ H 2 (g) [Cesium in water causes explosion] Fe reactivity to O 2 + H 2 O (fog)→ Fe 2 O 3 (rust) Iron Oxide (you leave your bike out in the fog and it rusts)

40 Rubidium,Cesium, & Francium in water XBms XBms

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 → H 2 (g) + ZnCl 2

47 Color Change and Precipitate Formation 2 KI + Pb(NO 3 ) 2 → 2 KNO 3 + PbI 2 (s) 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.

51 What do you notice about the letters on the periodic table?

52 Periodic Table of Elements Groups: (Families) the vertical columns on the periodic table. Periods: Horizontal Rows. Each element is represented by a symbol Symbols are one to three letters The first letter is always capitalized, 2 nd & 3 rd letters are always lower case. Often the chemical symbols coincide with the spelling of the element, but other times the symbols were derived from the Latin name for the element.

53 Periodic Table of Elements, cont. Metals: Good conductors of heat and electricity. In general, they are malleable, ductile, lustrous, etc Non-Metals: Poor conductors of heat and electricity. Solids are brittle Metalloid: Having characteristics of both metals and non-metals

54

55 Chemical symbols Can be used to represent chemical formulas. The numerical subscripts tell the proportion of each element in a compound or diatomic element.

56 Tell me how many of each type of atom are in the following: NaCl CO 2 HF H 2 ZnCl 2

57 IUPAC International Union (of) Pure & Applied Chemistry IUPAC-developed a systematic way of naming elements that are 1st synthesized

58 One-syllable root word to represent numbers 0-nil 1-un 2-bi 3-tri 4-quad 5-pent 6-hex 7-sept 8-oct 9-enn

59 To write the name for synthesized elements: Use the root word for each number in the element Add –ium to the ending

60 Examples 110→… 124 →… 139 →....

61 To write the chemical symbol for the element: Take the 1st letter of each root word, capitalize it and lower case the 2nd and 3rd

62 examples 113 → 156 → 213 →

63 Law of Definite Proportions: States that regardless of the amount, a compound is always composed of the same elements in the same proportion, by mass. For example, water, is always H 2 O… Which is ~11% Hydrogen And ~89% oxygen

64 Percent by mass (%): mass of element x 100 Mass of compound

65 Mass of Compound: the sum of the masses of the individual elements that make up the compound.

66 Example A sample of an unknown compound contains 5.3 g oxygen and 20.0 g of copper. What is the percent by mass of each element in the compound?

67 Law of Multiple Proportions States that when different compounds are formed by a combination of the same elements, different masses of one element combine with the same relative mass of the other element in a ratio of small whole numbers

68 Ratios: Compare the relative amounts of any items or substances Express the relationship of elements in a compound

69 Mass Ratio 1. Mass of element in a compound = ratio Mass of other element in compound 2. Mass ratio compound I = small whole # Mass ratio compound II *find the mass ratio for each compound, then divide the two ratios to give a small whole # ratio

70 Example: Analysis Data of Two Iron Compounds Are Compounds I and II the same compound? If not, use the law of multiple proportions to show the relationship between them. Compound Total Mass Mass Fe (g) Mass O (g) Mass % Fe Mass % O I II

71 Example cont.


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