3 Objectives Classify matter according to its composition Distinguish among elements, compounds, homogeneous mixtures and heterogeneous mixturesRelate the properties of matter to structure
4 ChemistryInvestigates and explains the structure, composition, and behavior of matter (how it is made and organized) It is the WHAT, HOW, and WHY of stuff
5 Composition and Behavior But what is matter? Matter is anything that takes up space and has mass. …and what is mass? Mass is the measure of the amount of matter that an object contains. Question: What is the SI unit for mass?
6 Properties describe the characteristics and behavior of matter Properties of MatterProperties describe the characteristics and behavior of matterHow do I determine the properties of matter?Examine itManipulate it (burn it, dissolve it, mix it)Take measurements
7 The Macroscopic View of Matter Macro – prefix – what does it mean? If you can touch, feel, smell, taste or see it, you are viewing matter from a macroscopic perspective
8 The Submicroscopic View of Matter Submicro – prefix – what do you think it means?SubmicroscopicSo small that you can’t see it with a powerful microscope!You are “viewing” the world of atomsNo one has ever seen a single atom, but there is indirect evidence that supports its existence
9 Models in ChemistryGive an example of how a model is used? A scientific model is a thinking device that helps you: 1) Understand and explain the observed behavior of matter 2) Predict behavior that has yet to be observed Must be supported by experiments
10 Models in ChemistryWhat do the football team, school choir, chemistry class, and U.S. Congress have in common? All composed of people. In the same way aspirin and sucrose have the same kinds of atoms.
11 Classifying MatterQUALITATIVE: Observation without measurement Ex: Strong girl, blue dress, Tall man QUANITATIVE: Observation with measurements Ex: 100 lbs., 5 dresses, Man is 6 ft. tall
12 Pure substance or a mixture? PURE SUBSTANCE: Matter that has the same fixed composition and properties (element or compound)MIXTURE: Combination of two or more substances in which the basic identity if each substance is not changed - composition is variable
13 Pure SubstancesELEMENTS: Substances that cannot be broken down into simpler substances (simplest form of matter)There are ~117 elements, 92 occur naturally on EarthCOMPOUNDS: Chemical combinations of two or more elements, joined together in fixed proportions with a unique set of properties
14 MixturesCan be separated through physical processes – name a phsyical processPHYSICAL CHANGE: A change in matter that does not involve a change in the identity of the individual substancesExamples: freezing, melting, evaporating, cuttingPHYSICAL PROPERTIES: characteristics matter exhibits without any change in its identityExamples: solubility, melting point, density
15 Mixtures2 Types of mixtures: Heterogeneous: a mixture with different compositions Has clear and distinct regions, called phases. Homogeneous: a mixture that is the same throughout (constant composition) also called a SOLUTION Solutions can have water, gases, solids
16 Ex: Stainless Steel (Fe, Cr, Ni), Brass (Cu and Zn) Mixtures (cont)ALLOYS: solid solutions that contain metals and sometimes nonmetals. No water!Ex: Stainless Steel (Fe, Cr, Ni), Brass (Cu and Zn)
17 Mixtures (Cont) Aqueous solutions: Contain water. Solute: The substance that is dissolved.Solvent:The substance that dissolves the solute.Example:In Kool-Aid what is the solute and what is the solvent?
20 Organizing elementsPeriodic table organizes elements and provides chemical information.Periodic tables in textbook on p , back cover.Chemical symbols are universal shorthand- 1 or 2 letter symbols.Ex: O (oxygen) -corresponds to English nameCu (copper)- corresponds to Latin name (cuprum)
21 Compounds More than 10 million compounds (Common compounds on p. 30) FORMULA: Combination of chemical symbols that shows which elements and how many make up a compoundEx: H2O (water), C12H22O11 (Sucrose)
22 Group Activity: Pure vs. Compound Homogeneous vs. Heterogeneous Grouping/Sorting Matter ActivitySugar and SandSalt and WaterSulfur (S)Stainless SteelMilkSpaghetti and meatballs
23 ActivityOrganize the matter from the list below into 2 categories~ PURE and MIXTURE Granola Dihydrogen MonoxideSugar UraniumSterling Silver InkAir Natural GasDiamonds Bronze
24 ActivityNow…Separate your PURE matter into elements and compounds.
25 ActivityNOW…Separate your MIXED matter into homogeneous and heterogeneous.