Chapter 1,2,&3 Notes - Week 2 Chapter 1 Introduction Matter...

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Week 2: 08/24/2016 Chapter 1Introduction:Matter and Measurement 1.1The Study of ChemistryWhy Study Chemistry?Five Main Branches of Chemistry1.Organic Chemistry2.Inorganic Chemistry3.Analytical Chemistry4.Physical Chemistry5.BiochemistryIn this science we study matter, its properties, and its behavior.What is Matter?- Matter is anything that has mass and occupies space. Chemistry explains properties and behavior of matter based on structure and events at the Atomic and molecular levelsAtoms are the building blocks of matter Each element is made of the same kind of atomA molecule is made of two or more atoms1.2 Classifications of Matter States of MatterSubstances can exist in the solid, liquid or gas stateSolid- particles are closely packed, fixed position, fixed shape and volume Liquid- particle closely not as much as solids allowing them to move, not rigid, can’t be squashed, fixed volume, no fixed shapeGas- helium, less dense than air unreactive, particles not closely packed, not rigid can be squashed, no fixed shape or volume. It can assume the shape and volume of its container Anysubstance can exist in the solid, liquid, or gas state. Pure Substances Pure substances Elements- if not mixed with other elements, are considered pure substances and are composed of only one type of atom. Compounds – combinations of atoms of more than one type of element. Example: Water (H2O)
oLaw of constant composition: Molecules – group of atoms (two or more) bonded chemically: Not all molecules are compounds: H2(not a compound) NH3(compound) Elements and compounds (&molecules) have definite compositions, and each has a set of properties that are unique. And are considered pure substances Know the element names and symbols for the first 36 elements MixturesHomogeneous Mixtures (also called solutions) Constant composition throughout Examples: air, salt water, metal alloys Heterogeneous Mixtures Non-uniform composition Mixtures: 2 or more pure substances that exist together but are not combined chemically Components of a mixture can be separated 1.2Properties of MatterPhysical PropertiesCan be observed without changing a substance into another substanceoBoiling point, density, mass, volume, melting point, color, ductility, luster, etc. Chemical PropertiesCan only be observed when a substance is changed into another substanceoFlammability, reactivity with acidMelting point of aluminum (P)Ability of nitric acid to dissoble copper ( C )Important: Mixtures can have properties distinct from any of the individual substances making up the mixture. Intensive PropertiesAre independent of the amount of the substance that is present (useful for identifying substances). Extensive Properties Physical and chemical changes
Physical changesThese are changes in matter that do not change the composition of a substance Chemical ChangeChanges of state (phase changes) Sublimation: solid going to a gasDeposition: gas going to a solid Chemical: Rusting,Evidence: Gas generated, heat evolved/ absorbed, color change

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