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Introduction to Chemistry

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1 Introduction to Chemistry
Chapters 1 and 2 Introduction to Chemistry Matter and Change

2 What is Chemistry?

3 What is Chemistry? The study of matter, its composition, properties, and the changes it undergoes. The interaction between matter and energy

4 What is Chemistry? Applied Chemistry ­ using chemistry to attain certain goals ­ Technology Pure Chemistry­ gathers knowledge for knowledge sake

5 Matter and Its Properties
Anything that has mass and volume is considered to be a form of matter Mass: The amount of matter in an object. Volume: The space that matter takes up.

6 Properties and Change in Matter
Physical Properties: can be observed and measured without changing the substance’s composition.

7 Physical Properties Conductivity Color Density Melting point
Boiling point Malleability Ductility

8 States of Matter

9 Physical Changes Changes the appearance, without changing the composition of the matter. Melting, dissolving, ­ boiling

10 Phase Changes are Physical Changes
Solid: definite volume and shape Liquid: definite volume, indefinite shape gas: indefinite volume and shape Solid Liquid Gas

11 Classification of Matter
What are Mixtures?

12 Mixtures Made up of two or more substances physically combined. Each part keeps its own individual properties. Examples: Air, wood, tea, Consist of more than one kind of matter. Do not have a chemical formula.

13 Orange juice is a mixture of:
Water – H2O Fructose – C6H12O6 Citric Acid –C6H8O7 and many more compounds… Most things around us are mixtures

14 Mixtures Heterogeneous:
Non­uniform composition. Chocolate chip cookie, gravel, soil. Homogeneous: Same composition throughout. Kool­aid, air, tea called solutions.

15 Solutions Homogeneous mixture­ called a solution
Mixed molecule by molecule Can occur between any state of matter. Solid in liquid­ Kool­aid Liquid in liquid­ 3% hydrogen peroxide Gas in gas­ air Liquid in gas­ water vapor Gas in liquid­ soft drink Solid in solid ­ brass

16 Separating Mixtures

17 Separating Mixtures Components are physically mixed
Use differences in the physical properties of components of the mixture to separate the mixture Solubility Density Boiling point Molecular structure

18 Filtering and Decanting

19 Filtering

20 Magnetism

21 Distillation

22 Chromatography the separation of a mixture by passing it in solution or suspension or as a vapor (as in gas chromatography) through a medium in which the components move at different rates.

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24

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26 Crystallization

27 Classification of Matter
Pure Substances

28 Classification of Matter
Pure substance pure form of matter ­ consists of – an element or a compound. Has a chemical formula. Carbon dioxide – CO2 Hydrogen – H2 Sodium – Na Water – H2O

29 Pure Substances?

30 Basic Building Blocks of Matter Atoms ­ Elements ­ Compounds
are the basic units of matter The smallest unit of an element that maintains the properties of that element.

31 Basic Building Blocks of Matter Atoms ­ Elements ­ Compounds
pure substances made of only one type of atom Na H2 Pb O2 S8

32 Most of the elements do not
exist in their elemental state, but exist in compounds. Why do you think this is? 2 Na + Cl2  2 NaCl

33 The most common element is hydrogen, more than 90% of the
atoms in the known universe are hydrogen. Oxygen and silicon make up more than 70% of the Earth’s crust. Living things are composed primarily of four elements: carbon, hydrogen, oxygen, and nitrogen.

34 Compounds Substances made from the chemical bonding of two or more different elements. ( NaCl H2O MgO ) Substances that can only be broken down by chemical methods. Has completely different properties from the constituent elements that make it up.

35 Molecule: a group of atoms held together by bonds
Molecule: a group of atoms held together by bonds. It may contain 2 or 2000 atoms

36 Hydrogen atom Carbon atom Oxygen atom Vitamin C – Ascorbic Acid

37 Vocabulary Molecule Compound two or more atoms that can
be the same or different Compound – two or more different kinds of atoms

38 Homogeneous Mixture (solution)
MATTER yes Can it be separated no by physical means? MIXTURE PURE SUBSTANCE yes Is the composition uniform? no yes Can it be decomposed by chemical means? no Homogeneous Mixture (solution) Heterogeneous Mixture Different atoms: Compound Same atoms: Element

39 (a) Atoms of an element

40 (b) Molecules of an element

41

42

43 Which is it? PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?

44 Which is it? PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?

45 Which is it? PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?

46 PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?

47 PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?

48 PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?

49 ATOM, ELEMENT, MOLECULE, COMPOUND?
B C A D E

50 ATOM, ELEMENT, MOLECULE, COMPOUND?
B C A D E

51 Chemical Changes

52 Chemical Reactions Reactants – starting material(s) ­ Products­ - ending material(s) The reactants turn into the products. Reactants  Products Iron + Sulfur  Iron sulfide

53 Chemical Properties Observable only when one substance reacts with another substance. A chemical property of O2 is that it supports combustion • CH4 + 2O2  CO2 + 2H2O Methane and oxygen produce carbon dioxide and water

54 Chemical Properties Reactivity with acids Reactivity with bases
Reactivity with oxygen Reactivity with hydrogen Reactivity with water Reactivity with …………… etc. etc. etc. ……. Are there more chemical or physical properties of matter ?

55 Chemical Changes •Creates a new form of matter.
•A chemical reaction occurs.

56 Indications of a chemical reaction
Energy is absorbed or released Color change

57 Indications of a chemical reaction
Gas released A precipitate is a solid that forms­ during a reaction between two solutions and sinks.

58 Conservation of Mass Mass and matter can not be created or destroyed in ordinary (non nuclear) changes. All the mass can be accounted for. The total amount of mass remains the same in any chemical change so the mass of the reactants is equal to the mass of the products

59 Law of Conservation of Mass

60 water Sodium

61 Sodium reacts violently with water
Sodium reacts violently with water. All the matter is still there, just in another form. The energy has simply changed from chemical potential energy to heat and light energy.

62 Periodic Table and Elements

63 Which are solids, liquids, gasses?

64 Symbols of Elements First letter is always capitalized
Second letter is never capitalized CO vs. Co Latin and German origins of some element names

65 Symbols of Elements Sb – antimony K – potassium Na – sodium Pb – lead
Sn – tin Fe – iron W – tungsten Ag – silver Au – gold Cu – copper Co – cobalt H – hydrogen N – nitrogen F – fluorine C – carbon O – oxygen Ca – calcium Hg ­ mercury

66 Periodic Table Speller https://www.bgreco.net/periodic/


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