Chapter 1-3: Classifying Chapter 1-3: Classifying MatterMatter

Matter Matter

Anything that has volume and massAnything that has volume and mass

All matter is composed of atomsAll matter is composed of atoms– An atom is the smallest unit of an element that An atom is the smallest unit of an element that

maintains the properties of that elementmaintains the properties of that element– Atoms can be physically mixed or chemically Atoms can be physically mixed or chemically

joined together to make up all kinds of matterjoined together to make up all kinds of matter

Pure SubstancesPure Substances

Pure substancePure substance– A sample of matter, either a single element or A sample of matter, either a single element or

a single compound, that has definite chemical a single compound, that has definite chemical and physical propertiesand physical properties

– Examples include copper, oxygen, and Examples include copper, oxygen, and carbon dioxidecarbon dioxide

Pure SubstancesPure Substances

Elements Elements – Pure substances that contain only one type of Pure substances that contain only one type of

atomatom– Each element has its own chemical symbol on Each element has its own chemical symbol on

the periodic tablethe periodic table

Pure SubstancesPure Substances

MoleculesMolecules– Elements can exist as single atoms or as Elements can exist as single atoms or as moleculesmolecules

– A molecule is the smallest unit of a substance A molecule is the smallest unit of a substance that keeps all the physical and chemical that keeps all the physical and chemical properties of that substanceproperties of that substance

– It can consist of one atom or two or more It can consist of one atom or two or more atoms bonded togetheratoms bonded together

– Example: Helium versus HydrogenExample: Helium versus Hydrogen

Pure SubstancesPure Substances

CompoundsCompounds– A substance made up of atoms of two or more A substance made up of atoms of two or more

different elements joined by chemical bondsdifferent elements joined by chemical bonds– Compounds can be made from their elements Compounds can be made from their elements

and also broken down into their componentsand also broken down into their components

Pure SubstancesPure Substances

– Compounds are represented by formulasCompounds are represented by formulasHH22O- subscripts are placed to the lower right of the symbol of O- subscripts are placed to the lower right of the symbol of

the element the element

Subscripts represent the number of elements in a compound, Subscripts represent the number of elements in a compound, if only one atom is present, no subscript is usedif only one atom is present, no subscript is used

– Compounds can also be represented by structural Compounds can also be represented by structural formulas, ball and stick models, and space-filling formulas, ball and stick models, and space-filling modelsmodels

MixturesMixtures

MixtureMixture: A combination of two or more : A combination of two or more substances that are NOT chemically substances that are NOT chemically combinedcombined– Example: air is a mixture of nitrogen, oxygen, Example: air is a mixture of nitrogen, oxygen,

argon, and carbon dioxideargon, and carbon dioxide– Example: pure water is NOT a mixture Example: pure water is NOT a mixture

because H is chemically bonded to O to form because H is chemically bonded to O to form HH22OO

MixturesMixtures

The proportion of the materials in a The proportion of the materials in a mixture can changemixture can change

Because of this the properties of mixtures Because of this the properties of mixtures may varymay vary

Examples: sweetened iced tea, 14-karat Examples: sweetened iced tea, 14-karat goldgold

MixturesMixtures

Homogeneous mixturesHomogeneous mixtures– When pure substances are distributed evenly When pure substances are distributed evenly

throughout the mixturethroughout the mixture– The different components of the mixture The different components of the mixture

cannot be identified by looking at itcannot be identified by looking at it– Examples: air, gasoline, syrupExamples: air, gasoline, syrup

MixturesMixtures

Heterogeneous mixturesHeterogeneous mixtures– When pure substances are NOT evenly When pure substances are NOT evenly

distributed throughout the mixturedistributed throughout the mixture– You can see the different components in the You can see the different components in the

mixturemixture– Different parts of the mixture may have Different parts of the mixture may have

different propertiesdifferent properties– Example: ice tea, cerealExample: ice tea, cereal

Mixture v. CompoundMixture v. CompoundA mixture is composed A mixture is composed of two or more of two or more substances that are substances that are physically mixedphysically mixedProperties of mixtures Properties of mixtures reflect the substances it reflect the substances it containscontainsMixtures can have Mixtures can have varying proportionsvarying proportionsMixtures can be Mixtures can be separated based on the separated based on the physical properties of physical properties of the substancesthe substances

A compound is A compound is composed of two or composed of two or more elements more elements chemically joinedchemically joinedProperties of compounds Properties of compounds have different properties have different properties than the elements that than the elements that make them upmake them upCompounds have Compounds have definite proportionsdefinite proportionsCompounds can only be Compounds can only be separated into its separated into its components through components through chemical changechemical change

Chapter 1 VocabularyChapter 1 Vocabulary

ChemicalChemicalChemical reactionChemical reactionStates of matterStates of matterReactantReactantProductProductMatterMatterVolumeVolumeMassMassWeightWeightQuantityQuantityUnitUnitConversion factorConversion factor

Physical propertyPhysical propertyDensityDensityChemical propertyChemical propertyAtomAtomPure substancePure substanceElementElementMoleculeMoleculeCompoundCompoundMixtureMixtureHomogenousHomogenousHeterogenousHeterogenous