SOLUTIONS ACIDS AND BASES SOLUTIONS SOLUBILITY AND CONCENTRATION

SOLUTIONS, ACIDS AND BASES

SOLUTIONS, SOLUBILITY AND CONCENTRATION • Solution – mixture that has the same composition, color, density and taste throughout • Solute – substance being dissolved • Solvent – substance doing dissolving • Solutions can also be gaseous, like the air you breathe, or even solid, like brass and sterling silver

SOLUTIONS, SOLUBILITY AND CONCENTRATION • When forming a solution, there are three ways to speed up the rate of the dissolving process: • Stirring – brings more solvent in contact with solute • Increase surface area – by breaking up a solid, for instance, by crushing it into a powder, allows more solvent to come in contact with solute • Increase temperature – increasing temperature speeds up particles causing them to bump each other, breaking apart and coming in contact with solvent

SOLUTIONS, SOLUBILITY AND CONCENTRATION • Solubility – maximum amount of a solute that can be dissolved in a given amount of solvent at a certain temperature • Concentration – percent by volume of solute in solvent • Concentrated – large amount of solute in solvent • Dilute – small amount of solute in solvent

SOLUTIONS, SOLUBILITY AND CONCENTRATION Types of solutions: Saturated • Contains all solute it can hold at given temperature Unsaturated Supersaturated • Able to dissolve more solute at given temperature • Contains more solute than a saturated one • Solution is unstable

ACIDS, BASES AND SALTS • Acid – substance that produces hydrogen ions (H+) in solution • Four Properties of Acids: • Acids taste sour • Acids are electrolytes (can conduct electricity in a solution) • Acids are corrosive • Acids react with indicators to produce a predictable color

ACIDS, BASES AND SALTS • Base – substance that produces hydroxide ions (OH-) in solution; also accepts H+ from acids • Also called alkaline • Five Properties of Bases: • In undissolved state, many bases are crystalline solid • In solution, bases feel slippery • Bases have a bitter taste • Strong bases are corrosive • Bases react with indicators

ACIDS, BASES AND SALTS • Indicator – organic compound that changes color in the presence of acid or base • Ex. Litmus paper • Neutralization – chemical reaction between an acid and a base in a water solution that results in formation of salt and water • Salt – compound formed when ions of an acid combine with ions from a base

STRENGTH OF ACIDS AND BASES • The strength of an acid or base depends on how many acid or base particles dissociate into ions in water • Strong acid – ionizes almost completely in water • Weak acid – only partly ionizes in solution • Strong base – dissociates completely in solution

STRENGTH OF ACIDS AND BASES Strength The terms strong and weak refer to the ease in which an acid or base dissociates in a solution Concentration The terms dilute and concentrated are used to indicate the amount of acid or base dissolved in a solution *It is possible to have dilute solutions of strong acids and bases, as well as concentrated solutions of weak acids and bases.

STRENGTH OF ACIDS AND BASES • p. H – measure of concentration of H+ ions in a solution or how acidic or basic it is • p. H scale typically ranges from 0 - 14 Stron g Acid Weak Base Stron g Base

STRENGTH OF ACIDS AND BASES