Solutions, Acids, and Bases Chapter 8

Section 8-1 Formation of Solutions

Dissolving Substances can dissolve in water three ways: –Dissociation –Dispersion –Ionization Solute – what is being dissolved Solvent – the substance in which the solute dissolves

Dissociation Dissociation – process in which an ionic compound separates into ions as it dissolves.

Dispersion Dispersion – breaking into smaller pieces that spread throughout the water.

Ionization Ionization – the process in which neutral molecules gain or loose electrons (and form ions).

Properties of Liquid Solutions The three physical properties of a solution that can differ from those of its solute and solvent are –Conductivity –Freezing Point –Boiling Point

Heat of Solution During the formation of a solution, energy is either released or absorbed. The process is either endothermic or exothermic.

Rates of Dissolving Factors that affect the rate of dissolving include –Surface area –Stirring –Temperature

Section 8-2 Solubility and Concentration

Solubility Solubility – the maximum amount of a solute that dissolves in a given amount of solvent. Solutions are described as saturated, unsaturated, or supersaturated depending on the amount of solute in solution.

Solubility Saturated solution – one that contains as much solute as the solvent can hold at a given temperature. Unsaturated Solution – a solution that has less than the maximum amount of solute that can be dissolved.

Solubility Supersaturated Solution – one that contains more solute than it can normally hold at a given temperature. These solutions are very unstable.Supersaturated Solution

Factors Affecting Solubility The factors that affect the solubility of a solute are –Polarity of the solvent (like dissolves like) –Temperature –Pressure

Concentration of Solutions Concentration can be expressed as –Percent by volume –Percent by mass –Molarity

Percent by Volume Volume of solute Volume of solution x 100%

Percent by Mass Mass of solute Mass of solution x 100%

Molarity Molarity = Moles of solute Liters of solution

Summary How are solutions with different amounts of solute described? What factors determine the solubility of a solute? What are three ways to measure the concentration of a solution?

Section 8-3 Properties of Acids and Bases

Properties of AcidsAcids Some general properties of acids include –Sour taste –Reactivity with metals –Ability to produce color changes in indicators Indicator – any substance that changes color in the presence of an acid or base.

Properties of Bases Some general properties of bases include –Bitter taste –Slippery feel –Ability to produce color changes in indicators

Neutralization and Salts Neutralization – the reaction between an acid and a base. The neutralization reaction between an acid and a base produces a salt and water.

Neutralization and Salts Example: HCl + NaOH NaCl + H 2 O Since all acids have H (hydrogen) ion and all bases have OH (hydroxide) ion, when the two mix, they make water and an ionic compound (known as a salt).

Proton Donors and Acceptors Acids can be defined as proton donors, and bases can be defined as proton acceptors.

How is an acid a proton donor? All acids contain an H (hydrogen) ion. + e-e-

Summary What are some general properties of acids and bases? What are the products of neutralization? What are proton donors and proton acceptors?

Section 8-4 Strength of Acids and Bases

The pH ScalepH The lower the pH value, the greater the H 3 O + ion concentration. The higher the pH value, the lower the H 3 O + ion concentration.

StrongStrong Acids & Bases When strong acids dissolve in water, they ionize almost completely. Strong bases dissociate almost completely in water

Electrolytes Electrolyte – a substance that ionizes or dissociates into ions when it dissolves in water. Resulting solution can conduct electricity. Strong acids and bases are strong electrolytes because they dissociate or ionize almost completely in water.