Solutions

SolutionsSubtopics include: (1) Describing Solutions, (2) Concentrations, (2)

Solubility & (3) the Effects of Solutes on Solutions.

SolutionsDescribing 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.

Concentrations Express the concentrations of solutions in

terms of percent by mass, percent by volume, parts per million and molarity.

Use Table T to calculate problems relating to concentrations.

Describe the preparation of a solution given the molarity.

SolubilityDefine: miscible, saturated, unsaturated,

solubility, supersaturation. Describe factors that effect solubility.Use “solubility rules” to predict the

solubility of an ionic compound in water. Interpret and construct solubility curves.Use solubility curves to distinguish among

saturated, supersaturated, and unsaturated solutions.

Apply the “like dissolves like” rule to real-world situations.

Effects of Solutes on Solution

Define: boiling point, freezing point and electrolytes.

Explore the effect of solutes on the boiling point and freezing point of solutions.

Solve problems involving freezing point depressions and boiling point elevation (colligative properties).

How can we describe the behavior of electrolytes in a 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.

Molecular Set: 3 water molecules, 2 hydrogen florides, 2 Iodines

Aim: How can we

describe solutions?

Essential Questions:

1. What is a solution?

2. What are some types of solutions?

3. How do we separate 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?Water and rubbing alcohol have different densities so why don’t they separate themselves into layers based on their densities as shown in the picture?

Why do they form solutions instead?

What makes their atoms arrange together homogenously?

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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 and ionic substances. ii. Nonpolar substances dissolve other

nonpolar substances.

Solutions Exist Between Particles in Different States (Gas,

Liquid, Solid)!

Can you think of any examples.

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.

2. All mixtures of gases are solutions.

Solutions Among Various Phases of

MatterExample 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.

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?

E. Separating Solutions

1. Evaporation Separates dissolved SOLUTE from

SOLUTIONEx. Separating salt from water

2. Simple distillationSeparates 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.

Video ClipDistillationhttp://www.youtube.com/watch?v=mP4Hgui-g6U&playnext=1&list=PL73CDD6FFC04D04A4&feature=results_main

4. Chromatography Separates mixtures into their constituents by preferential absorption by a solid.

Ex. Separating ink dyes using paper chromatography.

Cont’d

Filtration

FiltrationSeparates large particles from mixtures but it does not separate solutions

Why is that?

Learning Check1) The solvent is the part of the solution that A. gets dissolved B. does the dissolving C. changes phase

3) What is a solution?

4) What are some types of solutions?

5) How do we separate 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. Separating Solutions1. 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.