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Chapter 2
Matter
MatterMatter – anything that has mass and takes up space
MassMass – measure of the amount of matter that an object contains
VolumeVolume – measure of the space occupied by the object
Extensive & Intensive Properties
What you observe when you examine a sample of matter is its properties.properties.
1.1. Extensive PropertyExtensive Property – a property that depends on the amount of matteramount of matter in a sample
Ex. Mass, volume, weight, length
2.2. Intensive PropertyIntensive Property – a property that depends on the type of mattertype of matter in a sample (prefix–in means within)
Ex. Hardness, color, odor, luster, conductivity, malleability, ductility, freezing point, boiling point, melting point, density
SubstancesSubstanceSubstance – Matter that has a uniform and definite
composition
• Either an element or a compound
• Also called pure substance
• Rarely found in nature
• Fixed proportions to each other
ExamplesExamples
Diamond Water
Gold Copper
Sugar Nitrogen
MixturesMixtureMixture – a physical blend of two or more
substances that are not chemically combined
• Do not exist in fixed proportions to each other
• Most natural substances are mixtures
• Can usually be separated back into its original components
ExamplesExamples
Concrete Soil
Salt water Milk
Coke Gasoline
Fruit salad Atmosphere
ExamplesExamples
Concrete Soil
Salt water Milk
Coke Gasoline
Fruit salad Atmosphere
Two Types of Mixtures
Homogeneous Mixture (solution)Homogeneous Mixture (solution) – a mixture in which the composition is uniform throughout.
• Consists of a single phase
• Can’t see them separately or separate them physically
ExamplesExamples
stainless steel
air
olive oil
vinegar
Two Types of Mixtures
Heterogeneous Mixture Heterogeneous Mixture – a mixture in which the composition is not uniform throughout.
• Consists of a two or more phases
ExamplesExamples
chicken soup
oil & vinegar mixed
milk
rice crispy treats
Separating Mixtures
Differences in physical properties can be used to separate mixtures
ExamplesExamples
coffee filters
draining pasta
Filtration Filtration – process that separates a solid from a liquid
Separating Mixtures
ExampleExample
separating water from other substances in the water
Distillation Distillation – process of boiling a liquid to produce a vapor and then condensing the vapor into a liquid
States of Matter
1. Solid1. Solid
2. Liquid2. Liquid
3. Gas3. Gas
States of Matter
SolidSolidDefinite shapeDefinite volume
Not easily compressed
CharacteristicsCharacteristics• Does not take the shape of the container• Particles packed tightly together, and often in orderly
arrangement• Almost incompressible• Expands only slightly when heated
States of Matter
LiquidLiquidIndefinite shapeDefinite volume
Not easily compressed
CharacteristicsCharacteristics• Take the shape of the container in which it is placed• Particles in close contact, but arrangement of particles
is not orderly (can flow past each other)• Almost incompressible• Expands slightly when heated
States of Matter
GasGasIndefinite shapeindefinite volume
Easily compressed
CharacteristicsCharacteristics• Take the shape of the container in which it is placed• Can expand to fill any volume• Particles are much farther apart• Easily compressed into a smaller volume
Physical Change
Physical ChangePhysical ChangeSome properties of a material change, but the composition of the material does not change
ExamplesExamples Changes of stateChanges of state such as boiling water,
condensation (boil, freeze, melt, condense)
Physical deformationPhysical deformation such as cutting, denting, stretching, breaking, crushing
Chemical Change
ExamplesExamples Silver spoon tarnishes
Metal rusts Methane burns
Methane burns Sugar ferments
Burn, rot, rust, decompose, ferment, explode, corrode usually mean a chemical change
Chemical ChangeChemical ChangeA change that produces matter with a different composition than the original matter
Elements
Element Element – simplest form of matter that has a unique set of properties.
• cannot cannot be broken down into simpler substances
ExamplesExamples Hydrogen
Nitrogen
Oxygen
Compounds
CompoundCompound – substance that contains two or more elements chemically combined in a fixed proportion.
• Compounds can be broken down into simpler substances by chemical means
ExamplesExamples
Sugar (C12H22O11)
Salt (NaCl)
Water (H2O)
Breaking Down Compounds
A chemical change is required to breakdown compounds into simpler substances
Some methodsSome methods
Heating
Sugar heat Carbon + Water compound element element
Electric current
Water electricity Hydrogen + Oxygen compound element element
Properties of Compounds
In general, properties of compounds are quite different from those of their component elements.
ExampleExample
Compound ---- Table Salt (NaCl)
Element ---- Sodium (Na) – soft, gray metal
Element ---- Chlorine (Cl) – pale yellow-green poisonous gas.
ElementElementSimplest form
CompoundCompound
SubstanceSubstanceDefinite composition
HomogeneousHomogeneousMixtureMixture
Uniform; also calleda solution
HeterogeneousHeterogeneousMixtureMixture
Nonuniform;Distinct phases
MixtureMixtureVariable composition
MatterMatter
Can be separated physically
Can be separatedchemically
Silver Salt StainlessSteel
Cement
Classifying MatterAny sample of matter is either an element, a compound, or a mixture
Chemical Symbols
Each element on the periodic table is represented by a one or two letter chemical symbol.
ExamplesExamples
Na – Sodium Au - Gold
C - Carbon K - Potassium
• The first letter of a chemical symbol is always capitalized.
• When a second letter is used, it is lowercase
Symbols Derived From Latin
Sodium Na
Potassium K
Antimony Sb
Copper Cu
Gold Au
Silver Ag
Iron Fe
Lead Pb
Tin Sn
Physical PropertiesPhysical PropertyPhysical Property – a quality or
condition of a substance that can be observed or measuredobserved or measured without changing the substance’s composition
ExamplesExamples
Appearance Density
Texture Malleability
Color Boiling Point
Odor Melting Point
Conductivity Hardness
Chemical Property
ExamplesExamples
Gasoline -- burns in air Iron -- rusts Baking Soda -- reacts with vinegar Copper -- rusts in waterTable salt -- does not react with vinegar
Chemical Property Chemical Property Ability of a substance to undergo a specific chemical change
• Chemical properties can be observed only when a substance undergoes a chemical change.
Recognizing Chemical Changes
ExamplesExamples
Gasoline -- burns in air Iron -- rusts Baking Soda -- reacts with vinegar Copper -- rusts in waterTable salt -- does not react with vinegar
Words such as burn, rot, rust, decompose, ferment, explode, and corrode usually signify a chemical change.
During a chemical change, the compositionof matter always changes.
Recognizing Chemical Changes
Precipitate – Precipitate – solid that forms and settles out of a liquid mixture
Ex.Ex. – ring of soap scum in your bathtub
Possible Clues Possible Clues •Transfer of energy•A change in color•The production of gas•The formation of a precipitate
The only way to be sure a chemical change has occurred is to test the composition of a
sample before and after the change
Law of Conservation of MassDuring any chemical reaction, the mass of the
products is always equal to the mass of the reactants.
ExampleExample
2H2 + O2 2H20
2g 2g = 4g
reactants = product
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