2Types of MixturesTypes of MixturesReview: When we classified matter, we learned
that mixtures can be classified as:
Homogeneous (visually the same throughout) or Heterogeneous visually different throughout)
What are some examples of each of these types of mixtures?
3SuspensionSuspension: : a a heterogeneousheterogeneous mixture of mixture of
2 or more substances2 or more substancesParticles areParticles are largelarge enough enough to settle out to settle out and can be and can be separated byseparated by filteringfilteringi.e. – Muddy i.e. – Muddy
waterwater
4Flour suspended in water (appears light blue
because blue light is scattered off the flour particles to a greater extent than red light)
Other examples:
•Chalk Dust suspended in the air
•Paint
6
Colloids:Colloids: homogeneoushomogeneous mixture of 2 or more mixture of 2 or more substances substances evenlyevenly blendedblended into one another.into one another.Substances Substances nevernever
separate (settle out)separate (settle out)
7What’s the What’s the differencedifference between a between a solution and solution and
colloidcolloid??
ColloidsColloids havehave largerlarger particlesparticles thatthat scatter light;scatter light; SolutionsSolutions havehave smallersmaller particlesparticles that do that do not scatter the lightnot scatter the light
Use the:
Is fog a Is fog a solution or solution or
colloid?colloid?
10
A A solutionsolution is... is...Def. - A homogenous mixture of two
or more substancesThe Formation of a solution is a physical change …NOTNOT a chemical
change.
11
Solute:Solute: the substance the substance that is that is being being dissolved dissolved
•Present in the smallest Present in the smallest amountamount
Solvent:Solvent: component component presentpresent in thein the largestlargest
amountamount (usually H(usually H22O).O).
12Types of Liquid Solutions
AqueousAqueousA solution with water
as the solvent
TinctureTinctureA solution with alcohol
as the solvent
13Solution ConcentrationSolution Concentration Refers to the amount of solute
dissolved in a solvent
5 grams5 grams of salt in of salt in 100 grams of 100 grams of waterwaterdilutediluteVSVS
35 grams35 grams of of salt in salt in 100 100 grams of grams of
waterwaterconcentratedconcentrated
100 g.
100 g.
5 g
35 g
14Concentrated vs. DiluteConcentrated vs. Dilute
A concentrated solution contains:
Large amount of SOLUTE in a small amount of SOLVENT
A dilute solution contains:
Small amount of SOLUTE dissolved in a large amount of SOLVENT
“from concentrate”
SUMMARY
17
Solid into a Solid (alloy):Solid into a Solid (alloy): two metals dissolved into two metals dissolved into one another. one another.
Solid into a Liquid:Solid into a Liquid: Salt Salt dissolved in water.dissolved in water.
Gas into a Liquid:Gas into a Liquid: COCO22 dissolved (under pressure) dissolved (under pressure) into a coke. into a coke.
18The air that we The air that we
breathe is also a breathe is also a solution because it solution because it is made up of many is made up of many
different gases.different gases.
78.09% Nitrogen
20.95% Oxygen
Argon, CO2, and other trace gasesThe “solvent”
20DissolvingDissolving Def: the process of creating a solution
through the mixing of solute and solvent particles
Can a solute be dissolved by any solvent? NO!! NO!!
21InsolubleInsoluble When a substance cannot be dissolved in a solvent...
OilOil waterwater
++ ==
The word solublesoluble refers to solutes that CAN be dissolved in a
particular solvent.
23SolubilitySolubilityA measure of how much solute
can be dissolved in a solvent under certain conditions (i.e. – temp. & pressure)
Example
24Limits of SolubilityLimits of Solubility
SupersaturatedSupersaturated:: more solute has been dissolved than is normally possible
Saturated: Saturated: the maximum amount of solute has been dissolved in the solvent
Unsaturated: Unsaturated: more solute can be dissolved in the solvent
A solution can be described as:
http://boyles.sdsmt.edu/supersat/
AlexanderOnly.asx
25Solubility GraphsSolubility Graphs
Solubility of KCL
0
10
20
30
40
50
60
0 20 40 60 100
Supersaturated
Unsaturated
SaturatedSaturated
Unsaturated
26
Any point directly on the line = Saturated
Any point below the line = Unsaturated
Shows the relationship between temperature and solubilityShows the relationship between temperature and solubility
27Dissolving Rate Dissolving Rate
Def. – The amount of time required for a solvent to dissolve a particular solute
“Speed of dissolving”
28
Dissolving Rates Dissolving Rates (Solid in a (Solid in a
Liquid &Liquid & Gas in a Liquid) Gas in a Liquid)
29Three Factors Affecting Dissolving Three Factors Affecting Dissolving Rate of a Rate of a Solid into a LiquidSolid into a Liquid::
1.1.TemperatureTemperature
2.2. StirringStirring
3.3. Surface Surface AreaArea
30TemperatureTemperature Increasing the temperature
causes an increase in kinetic energy of the solid solute and liquid solvent particles
As the particles move faster, they collide into each other more, thereby increasing the DISSOLVING RATE
31StirringStirringStirring also increases
dissolving rate
Stirring causes an increase in collisions between the particles in a solution
32Surface Area Def. – A measure of how much
exposed area a substance has Breaking, crushing, etc. are ways to
increase the Surface Area Increasing surface area allows more
solute to come into contact with the solvent; increases dissolving rate
VS.
33
PressurePressure has the greatest has the greatest effect on the solubility of a effect on the solubility of a
gas in a liquid! gas in a liquid!
Depends on:Depends on:
1.1. Pressure = solubilityPressure = solubility
2.2. Temperature= solubilityTemperature= solubility
3.3. Stirring = solubilityStirring = solubility
36
Day 4 – Water, Day 4 – Water, Electrolytes, Electrolytes,
and Ionic and Ionic SolutionsSolutions
Day 4 – Water, Day 4 – Water, Electrolytes, Electrolytes,
and Ionic and Ionic SolutionsSolutions
37
WaterWater is a polar is a polar molecule that can molecule that can
dissolve many dissolve many solutessolutes..
HO
H
-
+ +
HO
H
-
+ +
Hydrogen BondsHydrogen Bonds: the (+) end of one
water molecule attracts a (-) end of
another.
38Polar MoleculesPolar Molecules Def. – molecules with
‘charged’ regions due to the electronegativity of the elements Compare hydrogen and
oxygen in the water molecule
One side of a water molecule is slightly negative and the other is slightly positive.
40
Polar Polar solventssolvents dissolvedissolve polarpolar solutes.solutes.
Is oil polar????????Is oil polar????????
Why do you Why do you need soap to need soap to clean butter clean butter off a knife?off a knife?
41“Like Dissolves Like”
The charged ends of a polar solvent can separate the charged ends of a polar solute.
Nonpolar molecules – have an equal sharing of electrons between atoms
+-
Is vinegar polar or non-polar?Is salt polar or non-polar?
43
IonizationIonization The formation of ions
by solvent as it separates the solute particles in a solution
When you pour NaCl (salt) into water, ions are formed
Na+ or Cl-
NaNa++ClCl--
NaNa++
ClCl--
NaNa++
ClCl--
NaNa++ClCl--
NaNa++
ClCl--
ClCl--NaNa++
45ElectrolytesElectrolytes A solution in which the
solute has dissolved to create ions.
These dissolved ions allow the solution to conduct electricity.
46Types of Electrolytes NONELECTROLYTENONELECTROLYTE –
formed by solutes that DO NOT dissociate into ions in solution
STRONG ELECTROLYTESTRONG ELECTROLYTE – formed by solutes that COMPLETELY dissociate in solution
WEAK ELECTROLYTEWEAK ELECTROLYTE – formed by solutes that DO NOT COMPLETELY dissociate in solution
47Why is it dangerous to use electric appliances around
bathwater?
Distilled Water is pure water with NO dissolved salts or minerals.