Created by C. Ippolito September 2003 Matter and Energy Objectives: 1.explain why mass is used as a measure of the quantity of matter 2.distinguish the states of matter 3.describe the characteristics of elements, compounds, and mixtures 4.distinguish between physical and chemical properties 5.distinguish between physical and chemical changes 6.demonstrate an understanding of the law of conservation of mass

Created by C. Ippolito September 2003 Matter Anything that has mass and takes up space –Mass measures the quantity of matter –Weight force of gravity acting on mass

Created by C. Ippolito September 2003 States of Matter SolidSolid –definite shape and volume –particles close together –little/movement LiquidLiquid –shape of container and definite volume –particles have some separation –slide past each other viscosity – measures “ease” of flow miscible – liquids can mix immiscible – liquids cannot mix GasGas –indefinite shape and volume –particles far apart –particles have free movement (diffuse)

Created by C. Ippolito September 2003 Elements and Compounds Pure SubstancePure Substance - one kind of matter –Element made of one type of matter smallest part – atom cannot be chemically separated –Compound two or more types of matter chemically combined in fixed proportions smallest part – molecule can be chemically separated

Created by C. Ippolito September 2003 Mixtures two or more substances –not chemically combined –proportions not constant (definite) Heterogeneous Mixture –non uniform composition phases (substances) can be distinguished –oil and water, salt and pepper Homogeneous Mixture –uniform composition and appearance phases (substances) cannot be distinguished –liquids – solutions –solids – alloys (bronze, brass, steel)

Created by C. Ippolito September 2003 Properties of Substances Physical PropertiesPhysical Properties –substance itself Chemical PropertiesChemical Properties –action of the substance with other substances

Created by C. Ippolito September 2003 Physical Properties Extensive PropertiesExtensive Properties –vary with amount present Mass – measure in grams Length – measured in meters Volume – measured in milliliters (mL) or cubic centimeters (cm 3 ) Intensive PropertiesIntensive Properties –same regardless of amount Luster (shininess) Hardness Slipperiness

Created by C. Ippolito September 2003 DensityDensity –measures quantity of mass of a substance that occupies one unit of volume –density = MalleabilityMalleability –can be hammered into thin sheets DuctilityDuctility –can be drawn into fine threads or wires ConductivityConductivity –amount of resistance to flow of heat or electricity conductorsconductors –little resistance to flow insulatorsinsulators – large resistance to flow Boiling PointBoiling Point –temperature of phase change from liquid to gas Melting PointMelting Point –temperature of phase change from solid to liquid Intensive Properties

Created by C. Ippolito September 2003 Physical Changes changes that only affect appearance NOT composition –melt –melt – solid to liquid –boil –boil – liquid to gas –condense –condense – gas to liquid –freeze –freeze – liquid to solid –sublimate –sublimate – solid directly to gas separation of mixtures based on physical properties –Distillation –Distillation – uses differences in boiling points –Fractional Crystallization –Fractional Crystallization – uses solubility at different temperatures

Created by C. Ippolito September 2003 Chemical Changes composition of substance changes –two or more new substances with different properties burning digesting fermenting

Created by C. Ippolito September 2003 Conservation of Mass Antoine LavoisierLavoisier –studied burning of metals –found total mass of matter before and after chemical changes is the same in chemical changes –matter is neither created nor destroyed –it only changes its form

Created by C. Ippolito September 2003 Energy and Chemical Change EnergyEnergy –ability to do work or transfer heat –can be converted from one form into another WorkWork –done when an object is pushed or pulled some distance

Created by C. Ippolito September 2003 Energy Forms Potential EnergyPotential Energy (E P ) depends on position or composition stored energy Kinetic EnergyKinetic Energy (E K ) depends upon motion “working” energy

Created by C. Ippolito September 2003 Energy & Chemical Change All chemical changes are accompanied by a change in energy –Endothermic Reaction Heat energy is absorbed Products have more energy than reactants Surroundings become colder –Exothermic Reaction Heat energy is released Products have less energy than reactants Surroundings become warmer

Created by C. Ippolito September 2003 Matter and Energy Law of the Conservation of EnergyLaw of the Conservation of Energy –energy is always conserved. –amount of energy in the universe is constant –energy is neither created nor destroyed –energy can only change form Albert Einstein –matter can change into energy –energy can change into matter –E = mc 2