Warm-up #4

▪What is the difference between a homogenous mixture and a heterogeneous mixture?

Warm-up #4

▪Homogeneous: all looks the same (uniform)

▪Heterogeneous: can clearly see the different particles

Separation Techniques

Review: Mixture or Pure Substance?

Pure substance Mixture Pure substance

Review: Soluble or Insoluble?

Review: Homogeneous or Heterogeneous?

Homogeneous Heterogeneous

Mixtures

▪What is a mixture?▪A substance made up of two or more types of particles that are NOT chemically bonded together

▪Can you separate the substances from each other?▪Yes!

SeparationTechniques

Sedimentation

Mixture type : Heterogeneous

How it works:

▪With time, the particles separate because the denser particles will sink to the bottom

▪We call this the sediment

DecantationMixture type : Heterogeneous

How it works:

▪Remove a layer of liquid (usually one from which a precipitate has settled)▪Pour off the top layer of liquid

FiltrationMixture type : Heterogeneous

How it works:

▪A heterogeneous mixtures is passed through a filter in order to separate the solid component from the liquid▪Part left in filter = residue

▪Liquid that comes out the bottom = filtrate

Often used in combination with decantation

Centrifugation

Mixture type : Heterogeneous

How it works:

▪The mixture is spun very fast and the centripetal force causes the different components of the mixture to separate

SiftingMixture type : Heterogeneous

How it works:

▪Pass a solid mixture through a sieve to remove different sized particles

Distillation

Mixture type: *Homogeneous*

How it works:

▪Since boiling point is a characteristic property we can heat the mixture and cause one component (usually water) to evaporate leaving the other component behind (ex: salt)

Quick Demo!