Solutions, Suspensions and Colloids
Acids, Bases and Salts
SolutionsAll solutions are made of very small particles that do not affect light beams with:Solute – the chemical that is dispersedSolvent – the chemical that causes dispersalExamples: Salt water, Sugar water, vinegar, Coke, Air, Gold jewelry
Properties of Solutions
• Solute is homogeneously dispersed • All properties are the same throughout
solution• Particle size is very small• Gravity does not affected solutions over time• Solute particles can be molecular(as a sugar
solution) or ionic (as a salt solution)• Ionic solutions will conduct electricity
Colloids
• A mixture with small undissolved particles that do not easily settle out.
• Particles are larger than a solution but smaller than a suspension
• Particles are large enough to begin to scatter light (Tyndall Effect)
• Examples: Milk, gelatin, whipped cream, mayonnaise,
Suspensions
• Much larger particles• Often totally blocks transmission of light• Gravity will remove the suspended particles in
time to clear the solvent• Heterogeneous dispersal of suspended
particles• Examples: Pepper, sand or dirt in water
solutions colloids suspensions
< 1 nm > 100 nm
-atoms-small molecules-ions
-aggregates of atoms, molecules or ions-macromolecules (proteins)
-clumps of particles,-mineral grains such as sand
Comparison of Solutions, Colloids, and Suspensions
solutions colloids suspensions
< 1 nm > 100 nm
More Comparison…
Transparent to Opaque
Translucent toOpaque
molecular motionBrownian motion
movement by gravity
coagulation – can settle
never settle
transparent(clear)
solutions colloids suspensions
< 1 nm > 100 nm
-dissolved in water electrolytes
(salts) gases glucose
-plasma proteins albumins globulins fibrinogen
-cellular stuff red blood cells white blood cells platelets
Using whole blood as an example…
Dissolving process in water
Na+
Cl-
1. Overcome attractive forces in solid
2. Hydration of soluteOrientation of water molecules around solute
Pure Water
H20
Non-electrolyte -No dissociation,all molecules in solution. No Ions are present to allow electrons to pass.
no conductivity
Types of solutes
Na+
Cl-
Strong Electrolyte -100% dissociation,all ions in solution
high conductivity
Types of solutes
CH3COOHCH3COO-
H+
Weak Electrolyte -partial dissociation,molecules and ions in solution
slight conductivity
Types of solutes
sugar
Non-electrolyte -No dissociation,all molecules in solution
no conductivity
Solubility of Solutes in Water
Temperature
Solu
bilit
y, g
/100
mL
wat
er Most solids(endothermichydration)
Some solids(exothermichydration)
All gases
How do I get sugar to dissolve faster in my iced tea?
Stir, and stir, and stir
Add sugar to warm tea then add ice
Grind the sugar to a powder
Fresh solvent contact and interaction with solute
Greater surface area, more solute-solvent interaction
Faster rate of dissolution at higher temperature
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