Chapter 9

Chemical reactions in aqueous solutions

solution

homogeneous mixture of two or more substances

solvent

substance present in the largest amount (moles); dissolves other substances

solute

dissolves in a solvent

electrolyte

a substance that dissolves in water to yield a solution that conducts electricity

dissociation

ionic compound breaks into its constituent ions

ionization

a molecular compound forms ions when it dissolves

nonelectrolyte

substance that dissolves in water to yield a solution that does not conduct electricity

strong electrolyte

an electrolyte that completely dissociates

weak electrolyte

compound that produces ions upon dissolving but exists in a solution predominantly as molecules that are no ionized

dynamic chemical equilibrium

when forward and reverse reactions occur at the same time the reaction is in this state

Strong acids

HCl, HBr, HI, HNO₃, HClO₃, HClO₄, H₂SO₄

precipitate

an insoluble product that separates from a solution

hydration

occurs when water molecules remove the individual ions from the ionic solid surrounding them so the substance dissolves

precipitation reaction

a chemical reaction in which a precipitate forms

solubility

the maximum amount of solute that will dissolve in a given quantity of solvent at a specific temperature

Polarity of water results from

electron distributions

Why is water a good solvent

because it is polar

molecular equation

compounds are represented by chemical formulas as though they exist in solutions as molecules or formula units

metathesis/double replacement reactions

reactions in which cations in two ionic compounds switch anions

ionic equation

Compounds that exist completely or predominantly as ions in solutions are represented as those ions

net ionic equation

includes only the species actually involved in the reaction

spectator ions

ions that appear on both sides of the equation; do not participate in the reaction

Steps to precipitation reactions

1. write and balance molecular equation, assume cations trade anions

2. Write ionic equation, separating strong electrolytes into constituent ions

3. Write net ionic equation by canceling out spectator ions

If both the reactants and products on both sides of a precipitation reaction are strong electrolytes,

all the ions in the solution are spectator ions and there is no net ionic equation, so no reaction takes place

A strong acid is also a

strong electrolyte

A strong base is also a

strong electrolyte

Strong bases

group 1 and 2 hydroxides: LiOH, KOH, NaOH, CsOH, SrOH, RbOH, Ca(OH)₂, Ba(OH)₂

A weak acid is also a

weak electrolyte

Most acids are

weak acids

neutralization reactions

occurs between acids and bases

Molarity

M = moles of substance/liters of solution

arrhenius acid

ionizes in water to produce H+ ions

arrhenius base

a base that dissociates in water to produce OH- ions

bronsted acid

a proton donor that donated protons to water to form a hydronium ion

monoprotic acid

has one acidic hydrogen to donate

bronsted base

a proton acceptor

polyprotic acid

more than one acidic hydrogen atom

diprotic acid

has two hydrogen atoms

monobasic

a base that only produces one mole of hydroxide per mole of compound

dibasic base

produce more than one ionizable hydroxide per mole of compound

lewis acid

accepts lone pair electron

lewis base

donates lone pair of electrons

amphoteric

both an acid and a base

example of amphoteric molecule

water

dilution

preparing a less concentrated solution from a more concentrated one

calculation for dilutions

M₁V₁ = M₂V₂

serial dilution

a series of dilutions that may be used to prepare a number of increasingly dilute solutions