AP Chemistry Chp 5: Aqueous Solutions

For an atom in its elemental form, the oxidation number is always ___

0

For any monatomic ion, the oxidation number equals the ___ on the ion

Charge

Nonmetals usually have ___ oxidation numbers, but not always

Negative

The oxidation number of oxygen is usually ___ in both ionic and molecular compounds

-2

In peroxides, which contain the O2^2- ion, oxygen has an oxidation number of ___

-1

The oxidation number of hydrogen is ___ when bonded to nonmetals and ___ when bonded to metals

+1, -1

The oxidation number of fluorine is ___ in all compounds.

-1

The halogens have an oxidation number of ___ in most binary compounds. Exception: when halogens are combined with oxygen, as in oxyanions, they have ___ oxidation states

-1, positive

General pattern for redox reactions

A + BX ---> AX +B

Other names for redox / oxidation-reduction reactions

Single-replacement, displacement

A list of metals arranged in order of decreasing ease of oxidation; also includes hydrogen.

Activity Series

In the activity series, the elements at the ___ are the most easily oxidized; referred to as active metals.

Top

In the activity series, the elements at the ___ have the lowest reactivity; referred to as noble metals.

Bottom

Any metals on the activity list can oxidize a metal listed ___ it.

Below

The amount of solute dissolved in a given quantity of solvent or quantity of solution

Concentration

Molarity is the number of ___ of solute in a ___ of solution

Moles, liter

When an ___ compound dissolves, the relative ___ of the ions introduced in the solution depend on the ___ formula of the compound.

Ionic, concentrations, chemical

___ contains three quantities -- molarity, moles ___, liters ___. So if we know any two of these we can calculate the third.

Molarity, solute, solution

Solutions that are used routinely in the laboratory are often purchased or prepared in concentrated form, called ___ ___.

Stock solutions

When a ___ is added to dilute a solution, the number of moles of ___ remains unchanged.

Solvent, solute

When a ___ is added to dilute a solution, the number of moles of ___ remains unchanged.

Solvent, solute

To calculate the volume needed to make a diluted solution, we use the equation ...

MconcVconc = MdilVdil

The process of reacting a solution of unknown concentration with one of known concentration

Titration

___ can be conducted with acid-base, precipitation, or redox reactions

Titrations

In order to titrate, you need a way to determine when the ___ ___ has been reached

Equivalence point

To determine the equivalence point for acid-base titrations, dyes known as acid-base ___ are used.

Indicators

The ___ change signals the ___ point, which usually coincides very nearly with the equivalence point.

Color, end

A homogenous mixture of two or more substances

Solution

The substance present in the greatest quantity

Solvent

The other substances present in the solution

Solute

Water itself is a poor conductor of ___, but the presence of ___ causes aqueous solutions to become good conductors

Electricity, ions

___ carry electrical charge from one ___ to the other, completing the electrical circuit

Ions, electrode

A substance whose aqueous solutions contain ions

Electrolyte

A substance that does not form ions in solutions

Nonelectrolyte

What compounds are considered electrolytes?

All covalent/ molecular compounds except for acids

___ is a very effective solvent for ionic compounds due to its polar nature. The partially positive H is attracted to the ___, and the partially negative O is attracted to the ___

Water, anion, cation

When the ions become surrounded by H2O molecules, the ions are said to be

Solvated

When a ___ compound dissolves in water, such as CH3OH, the solution usually contains intact ___ dispersed throughout the solution. Without any ____ particles, the solution is unable to conduct electricity.

Molecular, molecules, charged

Solutes that exist in solution completely or nearly completely as ions: consist of all soluble ionic compounds and a few molecular compounds

Strong electrolyte

Solutes that exist in solution mostly in the form of molecules with only a small fraction in the form of ions

Weak electrolyte

Chemists use a ___ arrow for weak electrolytes and a ___ arrow for strong electrolytes.

Single, double

Reactions that result in the formation of an insoluble product are known as ___ reactions

Precipitation

Precipitation reactions occur when certain pairs of ____ charged ions attract each other so strongly that they form an insoluble ionic ___.

Oppositely, solid

7 strong acids are

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

Double-replacement reactions follow the general formula:

AX + BY ---> AY + BX

An equation written with all soluble strong electrolytes shown as ions

Complete ionic equation

Ions that appear in identical forms among both the reactants and products of a complete ionic equation. They are present but play no direct role in the reaction.

Spectator ions

When spectator ions are omitted we are left with the

Net ionic equation

In a net ionic equation, ___ should be conserved. If every ion is a ___ then no reaction occurs!

Charge, spectator

___ reactions are when H^+ and OH^- ions come together to form H2O

Neutralization

Reactions where electrons are transferred between reactants.

Oxidation-reduction or redox reactions

The conversion of a metal into a metal compound by a reaction between the metal and some other substance in its environment.

Corrosion

When an atom, ion, or molecule has become more positively charged, we say that it has been ___.

oxidized

When an atom, ion, or molecule has become more negatively charged, we say that it has been ___.

Reduced

The loss of electrons

Oxidation

The gain of electrons

Reduction

The oxidation of one substance is always accompanied by the ___ of another as ___ are transferred between them

Reduction, electrons

Oxidation occurs when there is an ___ in oxidation number; reduction occurs when there is a ___ in oxidation number

Increase, decrease