Modern Chemistry Chapter 12- Solutions

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Modern Chemistry Chapter 12-Solutions
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Section 1- Types of Mixtures

• Solutions are homogeneous mixtures of two or more
  substances in a single phase.
• Soluble describes a substance as capable of being
  dissolved.
• Solvent is the dissolving medium in a solution.
• Solute is the substance that is dissolved in a
  solution.

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Types of Solutions

• Solutions can be in any of the three common
  physical states.
• solid- a mixture of metals called an alloy
• liquid- salt water, sugar water, Kool-Aid
• gas- the atmosphere

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Suspensions Colloids

• A suspension has large particles that settle out
  of a solvent. eg. muddy water
• A colloid has intermediate size particles. Also
  called an emulsion or a foam.

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Solutes electrolytes vs. nonelectrolytes

• An electrolyte is a substance that dissolves in
  water to give a solution that conducts
  electricity.
• A nonelectrolyte is a substance that dissolves in
  water to give a solution that does NOT conduct
  electricity.
• Do section review questions 1, 2, 6 on page
  406.

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Section 2- The Solution Process

• Factors that affect the rate of solution (how
  quickly a substance dissolves)
• Any process that increases the number of contacts
  between the solvent and the solute will increase
  the solution rate.
• increasing the surface area of the solute
• agitating (shaking or stirring) the solution
• heating the solvent

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Solutions

• Solution equilibrium is the physical state in
  which the opposing processes of dissolution and
  crystallization occur at equal rates.
• A saturated solution contains the maximum amount
  of dissolved solute.
• An unsaturated solution contains less than the
  maximum amount of dissolved solute.
• A supersaturated solution contains more dissolved
  solute than a saturated solution.

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Solubility

• Solubility is a measurement of how much solute
  will dissolve in a specific amount of solvent at
  a specific temperature to make a saturated
  solution.
• Likes dissolve likes- polar solvents dissolve
  polar solutes nonpolar solvents dissolve
  nonpolar solutes.
• Hydrationis the solution process with water as
  the solvent.
• Hydrates are ionic compounds that have formed
  crystals that have incorporated water molecules
  in their structure.
• Immiscible liquids are not soluble in one
  another. eg. oil water
• Miscible liquids dissolve freely in one another
  in any proportion. eg. water alcohol

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Solubility

• Increasing the pressure has no effect on the
  solubility of a solid in a liquid but does
  increase the solubility of gases in a liquid.
• Increasing temperature often increases the
  solubility of a solid in a liquid but decreases
  the solubility of a gas in a liquid.
• Henrys Law states that the solubility of a gas
  in a liquid is directly proportional to the
  partial pressure of the gas on the surface of the
  liquid.
• Effervescence is the rapid escape of a gas from a
  liquid in which the gas is dissolved.
• A solvated solute particle is surrounded by
  solvent molecules.
• Enthalpy of solution is the amount of heat
  absorbed by a solution when a specific amount of
  solute dissolves in a solvent.

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Problems

• Do section review questions 1, 2, 3, 5, 6
  on page 416.
• Read the Cross-Disciplinary Connection on page
  417 and answer the questions at the end of the
  reading.

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Section 3Concentrations of Solutions

• The concentration of a solution is a measure of
  the amount of solute dissolved in a given amount
  of solvent or solution.
• Molarity (M) is the number of moles of solute in
  one liter of solution.
• M mol L
• Do practice problems 1, 2, 3 on page 421.

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Solution Concentrations

• Molality (m) is the concentration of a solution
  expressed in moles of solute per kilogram of
  solvent.
• m mol
• kg
• Do practice problems 1 2 on page 424.

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Solution Concentrations

• Percent composition by mass () is a
  concentration that expresses the percent of
  solute in a solution.
• g solute x 100
• g solution
• Do section review problems 1, 2, 3 on page
  424.

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Chapter 12 Test Review

• multiple choice (30)
• define identify suspensions solutions
• define an alloy
• define identify electrolytes nonelectrolytes
• factors that affect the rate of dissolution
• definitions of unsaturated, saturated
  supersaturated solutions
• general rules for predicting whether a solute is
  soluble in a solvent
• definition of solubility
• effects of temperature pressure on the
  solubility of gases and solids in liquids
• definitions of molarity (M) and molality (m)
• solving molarity molality problems
• FORMULAS M mol/L m mol/kg