solutions subtopics include: (1) describing solutions, (2) concentrations, (2) solubility & (3)...
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SolutionsSubtopics include: (1) Describing Solutions, (2) Concentrations, (2)
Solubility & (3) the Effects of Solutes on Solutions.
SolutionsDescribing Solutions
Define: solution, solute, solvent, electrolyte, suspensions, colloidal dispersions.
Explore types of solutions.
Separation of Solutions.
Concentrations Express the concentrations of
solutions in terms of: percent, parts per million, mole fraction, molarity and molality.
Solve problems involving the measurements of concentration
SolubilityDefine: miscible, saturated,
unsaturated, solubility, supersaturation.
Describe Factors that effect solubility.
Use “solubility rules” to predict the solubility of an ionic compound in water.
Effects of Solutes on Solution
Effect of solutes on the boiling point and freezing point of solutions.
Solve problems involving freezing point depressions and boiling point elevation (colligative properties).
Solve problems involving solutions and chemical equations.
Effects of electrolytes on the behavior of the solution.
Describing Solutions Define: solution, solute, solvent, suspensions, colloidal dispersions, distillation filtration &
chromatography.
Explore types of solutions.
Identify homogenous mixtures that are not solutions.
Identify the process of separating solutions: distillation, filtration & chromatography.
Aim: What is a Chemical Solution?
Essential Questions:
1. What is a chemical solution?
2. What are some types of chemical solutions?
3. How do we separate chemical solutions? Explain.
Key Words:
solution, solute,
solvent, suspensions,
colloidal dispersions,
distillation, Filtration,
Chromatography.
Name Some Solutions!
Q: What are some solutions you have encountered today?
Which One is a Solution?
Salt Water
Oil Water A) The Salt
Water
B) The Oil
Water
C) Both
D) Neither
Deduction
Q: Based on the previous example, how can we describe a solution?
Notes
I. Describing SolutionsA. Definitions
1. Solution - homogenous mixture of a solute dissolved in a solvent.
Solutes, Solvents & Solutions
Solute
SolventSolution
Notes
2. Solute –
3. Solvent –
4. Solution –
What Makes Solutions
Homogenous?
Notes
B. “Like Dissolves Like”1. In a solution, all particles attract each
other with intermolecular forces of similar strength.i. Polar substances dissolve other polar
substances or ionic substances. ii. Nonpolar substances dissolve
nonpolar substances.
Gases
Given: Particles of different substances must attract each other with intermolecular forces of similar strength in order to form an even distribution, which is a solution.
Given: There are no intermolecular forces at work between particles in the gaseous phase
Deduction: Do gaseous particles form solutions (an even distribution)?
Strong Intermolecul
ar Forces
Weak Intermolecul
ar Forces
NoIntermolecul
ar Forces
Video
Dissolving Gasseshttp://www.youtube.com/watch?v=wOo5f_kvjFs
Dissolving NaClhttp://www.youtube.com/watch?v=
EBfGcTAJF4o
Notes
2. In gasses there are essentially no intermolecular forces, therefore all mixtures of gasses are solutions.
Can Solutions Exist Between Particles in Different States (Gas,
Liquid, Solid)?
Notes
C. States of Matter & Solutions1. The solute and solvent may be in different
phases as long as the particles are evenly distributed amongst each other.
i. Ex: Solid NaCl dissolved in liquid water.
ii. Ex: Gaseous CO2 is dissolved in liquid soda.
Solutions Among Various Phases of
Matter
Example Phase of Solute Phase of Solvent
Metallic Alloy Solid Solid
Table salt-water Solid Liquid
Ethyl alcohol-water Liquid Liquid
CO2-water (Soda) Gas Liquid
Air Gas Gas
How Do We Determine Which Substance is a Solute & Which is the
Solvent?
Notes
D. Identification of Solutes vs. Solvents 1. If the solute and solvent are in different
phases, then solute assumes the solvent’s phase.
2. If the solute and solvent are in the same phase, then the solvent is the one that there is more of.
All solutions are homogenous mixtures,
but not all homogenous mixtures
are solutions. Can you think of an example of a homogenous mixture that is
not a solution?
SuspensionsE. Suspensions – suspensions are formed by
the physical homogenous mixture of large particles. (Solutions are made by the chemical mixture of smaller particles).1. Suspensions will settle in time (solutions will
not).2. A light beam passing through a suspension
mixture will be visible (in a solution, it will not).
3. Ex. Sand + Water
Colloidal DispersionF. Colloidal Dispersion – formed when particles larger than those in solution but smaller than those in suspensions are dispersed in a medium
1. The terms dispersed substance vs dispersed medium are used for colloidal dispersion instead of solute and solvent.
2. A colloidal dispersion will not settle. 3. Tyndall effect: a light beam passing through a colloidal
dispersion will be clearly visible. 4. Ex. Whipped cream, mayonnaise, paint, gelatin &
marshmallow.
Tyndall Effect
Our Chemistry class has run out of salt and
we want to make a new batch from
collected sea water.
How do I separate the salt from the water?
G. Separating Solutions
1. Evaporation Separates dissolved SOLUTE from
SOLUTIONEx. Separating salt from water
2. Simple distillation
Separates SOLVENT from SOLUTIONEx. Obtaining pure water from sea water
3. Fractional distillation Separates one liquid from a mixture
of different liquids using differences in boiling points.Ex. Obtaining alcohol from wine or
oxygen/nitrogen from air.
4. Filtration
Separates dissolved SOLUTE from SOLUTION
Ex. Filtration of blood in kidneys
5. Chromatography
Separates mixtures into their constituents by preferential adsorption by a solid.
Ex. Separating ink dyes using paper chromatography.
Cont’d
Distillationhttp://www.youtube.com/watch?v=mP4Hgui-g6U&playnext=1&list=PL73CDD6FFC04D04A4&feature=results_main
Filtration
Chromatography
Learning Check1) The solvent is the part of the solution that
A. gets dissolved B. does the dissolving C. changes phase
2) Two homogenous mixtures not known as solutions are
_______________________ and _______________________.
3) What is a chemical solution?
4) What are some types of chemical solutions?
5) How do we separate chemical solutions? Explain.
NotesDescribing & Separating Solutions
I.Describing SolutionsA. Definitions
1. Solution - homogenous mixture of a solute dissolved in a solvent.2. Solute – substance dissolved.3. Solvent – substance that does the dissolving.4. Solution – A homogenous mixture composed on tiny particles.
B. “Like Dissolves Like”1. In a solution, all particles attract each other with intermolecular forces of
similar strength.i. Polar molecules dissolve other polar molecules and ionic compounds. ii. Nonpolar molecules dissolve nonpolar molecules.
2. In gasses there are essentially no intermolecular forces, therefore all mixtures of gasses are solutions.
C. States of Matter & Solutions1. The solute and solvent may be in different phases as long as the particles are
evenly distributed amongst each other.
i. Ex: Solid NaCl dissolved in liquid water.
ii. Ex: Gaseous CO2 is dissolved in liquid soda.
D. Identification of Solutes vs. Solvents 1. If the solute and solvent are in different phases, then solute assumes the
solvent’s phase. 2. If the solute and solvent are in the same phase, then the solvent is the one
that there is more of.
E. Suspensions – suspensions are formed by the physical homogenous mixture of large particles. (Solutions are made by the chemical mixture of smaller particles).1. Suspensions will settle in time (solutions will not).
2. A light bean passing through a suspension mixture will be visible (in a solution, it will not).
3. Ex. Sand + Water
F. Colloidal Dispersion – formed when particles larger than those in solution but smaller than those in suspensions are dispersed in a medium
4. The terms dispersed substance vs dispersed medium are used for colloidal dispersion instead of solute and solvent.
5. A colloidal dispersion will not settle.
6. Tyndall effect: a light beam passing through will be clearly visible.
7. Ex. Whipped cream, mayonnaise, paint, gelatin & marshmallow.
G. Seperating Solutions
1. Evaporation – separates dissolved SOLUTE from SOLUTION.i. Ex. Separating salt from water
2. Simple distillation – separates solvent from solutioni. Ex. Obtaining pure water from sea water
3. Fractional distillation – separates one liquid from a mixture of different liquids that have different boiling points.i. Ex. Obtaining ALCOHOL from wine or oxygen/nitrogen
from air.