1 mixtures day 1: chapter 14 lake nyos, cameroon courtesy of george kling, page 556-557
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MixturesMixturesDay 1: Chapter 14Day 1: Chapter 14
Lake Nyos, CameroonLake Nyos, Cameroon
Courtesy of George Kling, page 556-557Courtesy of George Kling, page 556-557
MixtureMixture2 or more 2 or more substances substances
physicallyphysically combinedcombined..
Two Types:Two Types:HomogeneousHomogeneous
Same throughoutSame throughout
HeterogeneouHeterogeneouss
Different throughoutDifferent throughout
HomogeneouHomogeneous?s?
HeterogeneoHeterogeneous?us?
MixtureMixture
Heterogeneous Heterogeneous MixturesMixtures
Suspension: two or Suspension: two or more substances more substances that do NOT mixthat do NOT mix
InsolubleInsoluble
SuspensionsSuspensionsa mixture appearsa mixture appears
uniform when shaken.uniform when shaken.Particles Settle out Particles Settle out Need to shake or stirNeed to shake or stirEx. orange juice, salad Ex. orange juice, salad dressingdressing
SUSPENSIONSUSPENSION
WHY? “LIKES DISSOLVES WHY? “LIKES DISSOLVES LIKES”LIKES”
Polar AND Nonpolar : NOT MIXPolar AND Nonpolar : NOT MIX
- Two substances only go Two substances only go together if they are alike. If together if they are alike. If they aren’t alike NOT go they aren’t alike NOT go together.together.
- Ex. Wax (nonpolar) and water Ex. Wax (nonpolar) and water (polar)(polar)
PolarityPolarity A molecule is A molecule is polarpolar when electrons are when electrons are
shared shared unequallyunequally. Have a (+) and (-) . Have a (+) and (-) endend
Molecules are Molecules are nonpolarnonpolar when when electrons are shared electrons are shared equallyequally between between atomsatoms
Water is very polarWater is very polar
SolutioSolutionn::HomogeneHomogeneous ous MixturesMixtures homogeneous mixture of 2 or homogeneous mixture of 2 or
more substances uniformly more substances uniformly spread throughout a medium.spread throughout a medium.
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Some DefinitionsSome DefinitionsA solution is a A solution is a
HOMOGENEOUSHOMOGENEOUS mixture of 2 or more mixture of 2 or more substances in a substances in a single phase. single phase.
One constituent is One constituent is usually regarded as usually regarded as the the SOLVENTSOLVENT and and the others as the others as SOLUTESSOLUTES..
Why Mix Uniformly?Why Mix Uniformly?
““Likes dissolve likes”Likes dissolve likes” D6 C30D6 C30
PolarPolar dissolves in dissolves in polarpolar
oror
NonpolarNonpolar dissolves in dissolves in nonpolarnonpolar
Uses: dry cleaningUses: dry cleaning
Microscopic CompositionMicroscopic Composition
Demo: ethanol/waterDemo: ethanol/water
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ColloidColloid
ColloidColloidMany types: we will look at one Many types: we will look at one
EMULSIONSEMULSIONSDo Do notnot settle out or dissolve settle out or dissolve
HOMOGENEOUS, HOMOGENEOUS,
Opaque, not let light throughOpaque, not let light through
Likes Dissolve LikesLikes Dissolve Likes
How do we get two thing that are How do we get two thing that are NOT alike to go together?NOT alike to go together?
Need Need Emulsifying Agent = Emulsifying Agent = thirdthird ingredientingredient
Emulsifying agent is BOTH polar Emulsifying agent is BOTH polar and nonpolarand nonpolar
3. Emulsion3. Emulsion
a mixture where polar a mixture where polar
substance is forced to mix substance is forced to mix uniformly with a nonpolar uniformly with a nonpolar substancesubstance
Held together by emulsifying agentHeld together by emulsifying agentEx. mayonnaise, glueEx. mayonnaise, glue
EMULSIONEMULSION
EMULSIFING EMULSIFING AGENTAGENT
Disk 10: Chapter 20Disk 10: Chapter 20
SOAPS AND DETERGENTSSOAPS AND DETERGENTS
SolutionsSolutions EmulsionsEmulsions
(Colloid)(Colloid)SuspensioSuspensio
nn
Uniform Uniform
HomogeneousHomogeneousDon’t Settle outDon’t Settle out ““Shake”Shake”
HeterogeneousHeterogeneous
TransparentTransparent
Light throughLight throughScatters LightScatters Light
OpaqueOpaqueTwo or more Two or more
phasesphases
Solute and Solute and solventsolvent
Alike (p/p or Alike (p/p or n/n)n/n)
Emulsifying Emulsifying AgentAgent
Polar and Polar and nonpolarnonpolar
Polar with Polar with nonpolarnonpolar
LETS COMPARE LETS COMPARE mixturesmixtures
Mixture Properties Mixture Properties & Particle Size& Particle Size
Dispersed particles too Dispersed particles too bigbig = = suspensionsuspension
Can filter outCan filter out Dispersed particles Dispersed particles smallsmall = =
solutionsolution
Pass through membranePass through membrane
NoneNone TyndallTyndall
effecteffectTyndallTyndall
effecteffect0.1 -1 nm0.1 -1 nm
Atoms, ionsAtoms, ions
Small culesSmall cules
1-200 nm1-200 nm
LargeLarge
moleculesmolecules
> 200nm > 200nm
Pass throughPass through Pass throughPass through Do NOTDo NOT
Pass throughPass through
ThroughThrough
membrane membrane Do NOTDo NOT
Pass through Pass through Do NOTDo NOT
Pass throughPass through
LIGHTSCATTERING
PARTICLESIZE
FILTRATION
DIALYSIS
PropertyProperty SolutionsSolutionsEmulsionsEmulsions
(Colloid)(Colloid) SuspensionSuspension