Chemistry Exam #2

Oxidation

Loss of electrons by a substance

Reduction

The gain of electrons by a substance

Displacement Reactions

A reaction between a metal and either an acid or a metal salt

Aqueous Solution

A solution in which water is the dissolved medium

Write the net ionic equation for the precipitation reaction that occurs when aqueous solutions of silver nitrate and potassium phosphate are mixed

Ag+ (aq) + PO4^-3 (aq) = Ag3PO4

Precipitate

An insoluble solid formed by a reaction in solution

Spectator ions

Appear on both sides of the equation

Dilution

Aqueous solutions of lower concentrations can then be obtained by adding water

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

Ex. Each H atom in the H2 molecule has an oxidation number of 0

For any monatomic ion, the oxidation number equals the ionic charge

Ex. K+ has an oxidation number of +1

Nonmetals usually have negative oxidation numbers

Ex. Oxygen usually = -2 Hydrogen usually = +1 Fluorine usually = -1

Salvation

Helps stabilize the ions in solution and prevents cations and anions from recombining

Which ions, if any, are spectator ions in this reaction? AgNO3 (aq) + NaCl (aq) = AgCl (s) + NaNO3 (aq)

Na+ (aq) and NO3- (aq)

Precipitation Reaction

Reactions that result in the formation of an insoluble product

Weak Electrolytes

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

Strong Electrolytes

Solutes that exists in solution completely or nearly completely as ions

Classify the following compounds as soluble or insoluble in water a.) cobalt (II) hydroxide b.) barium nitrate c.) ammonium phosphate

a.) insoluble b.) soluble c.) soluble

Neutralization Reaction

When a solution of an acid and a solution of a base are mixed.

What dissolved species are present in a solution of a.) KCN b.) NaCLO4

a.) K+ (aq) and CN- (aq) b.) Na+ (aq) and CLO4- (aq)