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Transcript of Matter And Energy An Introduction SAVE PAPER AND INK!!! When you print out the notes on PowerPoint,...
Matter And Matter And EnergyEnergy
An IntroductionAn IntroductionSAVE PAPER AND INK!!! When you print out the notes on PowerPoint, print "Handouts" instead
of "Slides" in the print setup. Also, turn off the backgrounds (Tools>Options>Print>UNcheck "Background Printing")!
The Nature of MatterThe Nature of Matter
Chemists are interested in the nature of matter Chemists are interested in the nature of matter and how this is related to its atoms and and how this is related to its atoms and molecules. More on this later in the coursemolecules. More on this later in the course
GoldGold MercuryMercury
Kinetic Nature of Kinetic Nature of MatterMatterMatter consists of atoms and molecules in motion Matter consists of atoms and molecules in motion
to varying degrees: from vibrating around a fixed to varying degrees: from vibrating around a fixed point to moving independent of all otherspoint to moving independent of all others
STATES OF MATTERSTATES OF MATTER•SOLIDSSOLIDS — have rigid shape, fixed — have rigid shape, fixed
volume. External shape can reflect the volume. External shape can reflect the atomic and molecular arrangement.atomic and molecular arrangement.–Reasonably well understood.Reasonably well understood.
•LIQUIDSLIQUIDS — have no fixed shape and — have no fixed shape and may not fill a container completely. may not fill a container completely. –Not well understood.Not well understood.
•GASESGASES — expand to fill their container. — expand to fill their container. –Good theoretical understanding.Good theoretical understanding.
Physical Physical PropertiesPropertiesWhat are some physical What are some physical
properties?properties?• colorcolor• melting and boiling melting and boiling
pointpoint• odorodor
Physical ChangesPhysical Changes– can be observed without
changing the identity of the substance
Some Some physical changes physical changes would bewould be
• boiling of a liquidboiling of a liquid• melting of a solidmelting of a solid• dissolving a solid in a dissolving a solid in a
liquid to give a liquid to give a homogeneous mixture homogeneous mixture — a SOLUTION.— a SOLUTION.
Chemical Properties and Chemical Properties and Chemical ChangeChemical Change
• Chemical change Chemical change or or chemical reactionchemical reaction — — transformation of one or transformation of one or more atoms or molecules more atoms or molecules into one or more different into one or more different molecules.molecules.
•Burning hydrogen (HBurning hydrogen (H22) in ) in oxygen (Ooxygen (O22) gives H) gives H22O.O.
Sure Signs of a Sure Signs of a Chemical ChangeChemical Change
• HeatHeat• LightLight• Gas Produced Gas Produced
(not from (not from boiling!)boiling!)
• Precipitate – a Precipitate – a solid formed by solid formed by mixing two mixing two liquids togetherliquids together
Physical vs. Chemical• Examples:
– melting point
– flammable
– density
– magnetic
– tarnishes in air
physical
chemical
physical
physical
chemical
Physical vs. Chemical• Examples:
– rusting iron
– dissolving in water
– burning a log
– melting ice
– grinding spices
Matter Flowchart
MATTERCan it be physically
separated?
Homogeneous Mixture
(solution)
Heterogeneous Mixture Compound
MIXTURE PURE SUBSTANCE
yes no
Can it be chemically decomposed?
noyesIs the composition uniform?
noyes
Colloids Suspensions
Element
Types of Mixtures
• Variable combination of 2 or more pure substances.
Heterogeneous –visibly separate phases
Homogeneous – Same throughout