Chapter 8Chapter 8Solutions, Solutions, Acids & Acids & BasesBases

Dissolving: Dissociation, Dissolving: Dissociation, Dispersion or IonizationDispersion or Ionization

Substances can dissolve in water Substances can dissolve in water by three ways:by three ways:1. dissociation1. dissociation2. dispersion2. dispersion3. ionization3. ionizationDissociation is the process by Dissociation is the process by which an ionic compound which an ionic compound separates into ionsseparates into ionsEx: NaClEx: NaCl

Dispersion is the process by which a Dispersion is the process by which a compound breaks into small pieces compound breaks into small pieces that spread throughout the waterthat spread throughout the waterEx: sugar dissolves in waterEx: sugar dissolves in waterIonization is the process by which Ionization is the process by which neutral molecules gain or lose neutral molecules gain or lose electrons (forming ions)electrons (forming ions)Ex: hydrogen chloride gas & water Ex: hydrogen chloride gas & water react to form hydronium ion (Hreact to form hydronium ion (H33OO++) ) and chlorine ion (Cl-)and chlorine ion (Cl-)

Physical Properties: Solute & Physical Properties: Solute & SolventSolvent

A solute is a substance whose A solute is a substance whose particles are dissolved in a solution particles are dissolved in a solution (often a solid)(often a solid)A solvent is the substance in which A solvent is the substance in which the solute dissolves (often a liquid)the solute dissolves (often a liquid)Solutes and solvents can take the Solutes and solvents can take the form of solids, liquids or gasesform of solids, liquids or gasesThe solution takes the state of the The solution takes the state of the solventsolvent

Conductivity is the ability of a Conductivity is the ability of a solution to conduct electricitysolution to conduct electricityEx: NaCl is a poor conductor until Ex: NaCl is a poor conductor until it is placed in water & dissociatesit is placed in water & dissociates

Energy Changes & Solution Energy Changes & Solution FormationFormation

During formation of a solution, During formation of a solution, energy is either released or energy is either released or absorbedabsorbedThe process is endothermic or The process is endothermic or exothermicexothermicForming attractions releases Forming attractions releases energy (exothermic)energy (exothermic)Breaking attractions requires or Breaking attractions requires or absorbs energy (endothermic)absorbs energy (endothermic)

Factors that Affect Dissolving Factors that Affect Dissolving RateRate

Factors that affect the rate of dissolving Factors that affect the rate of dissolving include surface area, stirring and include surface area, stirring and temperaturetemperature

Dissolving takes place at the surfaceDissolving takes place at the surface

The greater the surface area, the faster The greater the surface area, the faster the dissolvingthe dissolving

Stirring or shaking makes a substance Stirring or shaking makes a substance dissolve faster by increasing the surface dissolve faster by increasing the surface area exposed to the solventarea exposed to the solvent

Solubility & Factors Affecting Solubility & Factors Affecting SolubilitySolubility

Solubility is the maximum amount Solubility is the maximum amount of a solute that dissolves in a given of a solute that dissolves in a given amount of solvent at a constant amount of solvent at a constant temperaturetemperatureSolutions are classified as Solutions are classified as saturated, unsaturated or saturated, unsaturated or supersaturatedsupersaturatedThe classification depends on the The classification depends on the amount of solute in solutionamount of solute in solution

3 types of solutions3 types of solutionsA saturated solution is one that contains A saturated solution is one that contains as much solute as the solvent can hold as much solute as the solvent can hold at a given temperatureat a given temperature

An unsaturated solution has less than An unsaturated solution has less than the amount of solute that can be the amount of solute that can be dissolveddissolved

A supersaturated solution contains more A supersaturated solution contains more solute than the solution can normally solute than the solution can normally hold at a given temperaturehold at a given temperature

AcidsAcidsAn acid is a compound that An acid is a compound that produces hydronium ions (Hproduces hydronium ions (H33OO++) ) when dissolved in waterwhen dissolved in water

Some general properties of acids Some general properties of acids include sour taste, reactivity with include sour taste, reactivity with metals, and ability to produce color metals, and ability to produce color changes in indicatorschanges in indicators

An indicator is any substance that An indicator is any substance that changes color in the presence of an changes color in the presence of an acid or a baseacid or a base

BasesBasesA base is a compound that A base is a compound that produces hydroxide ions (OH-) produces hydroxide ions (OH-) when dissolved in waterwhen dissolved in water

Some general properties of Some general properties of bases include bitter taste, bases include bitter taste, slippery feel, and ability to slippery feel, and ability to produce color changes in produce color changes in indicatorsindicators

Strength of Acids and BasesStrength of Acids and Bases

pH of a solution is a measure of pH of a solution is a measure of its hydronium ion concentrationits hydronium ion concentration

A pH of 7 indicates a neutral A pH of 7 indicates a neutral solutionsolution

Water is the standard for pH 7Water is the standard for pH 7

The pH scale runs from 0 – 14The pH scale runs from 0 – 14

The lower the pH, the higher the The lower the pH, the higher the higher the hydronium ion higher the hydronium ion concentrationconcentration

The higher the hydronium ion The higher the hydronium ion concentration, the more acidic concentration, the more acidic the substance isthe substance isA high pH value means a low A high pH value means a low HH33OO++ concentration concentration

The lower HThe lower H33OO++ concentration, concentration, the more basic or alkaline the the more basic or alkaline the solution issolution is