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Chapter 4.1 Chapter 4.1 Compounds & Compounds &
MoleculesMoleculesPages 108 - 114Pages 108 - 114
Goal 1Goal 1
Distinguish between Distinguish between compounds and mixturescompounds and mixtures
CompoundCompound
Pure substance = Pure substance = own propertiesown properties
ChemicallyChemically bonded bonded elementselements
Chemical formula = Chemical formula = constant ratiosconstant ratios
MixturesMixtures Mix of >1 pure substanceMix of >1 pure substance Properties of each remainProperties of each remain Ratios of each varyRatios of each vary
Goal 2Goal 2
Recall how to read a Recall how to read a chemical formulachemical formula
Capital letter = elementCapital letter = element
SUBscript = number of atomsSUBscript = number of atoms
Front number = number of Front number = number of molecules / molesmolecules / moles
How many molecules? ___ How many molecules? ___ How many H atoms? ___How many H atoms? ___ How many O atoms? ___How many O atoms? ___
HH22OO
How many molecules? ___How many molecules? ___ How many H atoms total? ___How many H atoms total? ___ How many O atoms total? ___How many O atoms total? ___
5 H5 H22OO
How many molecules? ___How many molecules? ___ How many C atoms? ___How many C atoms? ___ How many H atoms? ___How many H atoms? ___ How many O atoms? ___How many O atoms? ___
CC66HH1212OO66
How many molecules? ___ How many molecules? ___ How many C atoms total? ___How many C atoms total? ___ How many H atoms total? ___How many H atoms total? ___ How many O atoms total? ___How many O atoms total? ___
3 C3 C66HH1212OO66
Goal 3Goal 3
Understand chemical Understand chemical structure modelsstructure models
Ball and stick modelBall and stick model Can be 3-D or 2-DCan be 3-D or 2-D Balls = atomsBalls = atoms Sticks = bondsSticks = bonds Bond lengthBond length Bond angleBond angle May not show relative atom sizeMay not show relative atom size
Structural formulaStructural formula 2-D (usually)2-D (usually) Short-hand of ball and stickShort-hand of ball and stick Only chemical symbols Only chemical symbols Bond length not shownBond length not shown Bond angles approximateBond angles approximate
Space filling modelSpace filling model 3-D3-D Sphere = atom and electron shellSphere = atom and electron shell Bond length and angles difficult to seeBond length and angles difficult to see
Goal 4Goal 4
Understand the effects Understand the effects chemical structure has chemical structure has
on properties of on properties of compoundscompounds
Network structureNetwork structure Elements bound continuously (net)Elements bound continuously (net) STRONG solidSTRONG solid High melting and boiling pointsHigh melting and boiling points
Silicon dioxide (quartz)Silicon dioxide (quartz)
Bonded ionsBonded ions Network of + and – charges (magnets)Network of + and – charges (magnets) STRONG solidSTRONG solid High melting and boiling pointsHigh melting and boiling points
Sodium chloride (salt)Sodium chloride (salt)
Molecular compoundsMolecular compounds Molecules attracted to each otherMolecules attracted to each other WEAKEST bondWEAKEST bond
Solid = most attractive forcesSolid = most attractive forces Liquid = attractive forcesLiquid = attractive forces Gas = least attractive forcesGas = least attractive forces