AP Chem Unit 4 Flashcards

Ionic Compound Made of

• metal (lose electrons) + nonmetal (gain electrons)

Physical properties of ionic compounds

• form crystals (crystalline solids) (meaning solid at room temp)

• Have high melting/boiling points

• Dissolved in water

• Conduct electricity when dissolved or molten (electrolytes)

• Overall neutral charge

Simple Rules for Solubility

1. Nitrate (NO3^-) and acetate (C2H3O2^-) salts are soluble

2. Alkaline (group 1A) salts and NH4^+ are soluble

3. Halide salts (second to last) are soluble (except Ag^+, Pb²+, Hg2²+)

4. Sulfate (SO4²-) salts are soluble (except with Ba, Pb²+, Hg2²+, Ca)

5. Strong acids are soluble (HCl, HBr, HI, HNO3, HClO4, H2SO4)

6. OH^- salts are insoluble ( except Group 1 hydroxides and Ca, Sr, Ba)

7. Most S²-, CO3²-, CrO4²-, PO4³- salts are insoluble (except alkaline salts and NH4^+)

Nitrate and acetate

• soluble

Alkali and NH4^+ solubility

• alkali - group 1A

• Soluble

Halide salts solubility

• soluble

• Except Ag^+, Pb^2+, Hg2²+

Sulfate salts solubility

• soluble

• Except BaSO4, PbSO4, Hg2SO4, CaSO4

Strong acids solubility

• soluble

• HCl, HBr, HI, HNO3, HClO4, H2SO4

OH- salts solubility

• insoluble

• Except Group 1 hydroxides, Ba²+, Sr²+, Ca²+

S²- solubility

• insoluble

• Except when containing alkali metal (group 1A) salt or NH4^+

CO3²- solubility

• Insoluble

• Except with alkali metals (group 1A) salts and NH4^+

CrO4²- Solubility

• insoluble

• Except for with alkali metals (group 1A) salts and NH4^+

PO4³- solubility

• insoluble

• Except with Alkali metals (group 1A) metals and NH4^+

Solution

• homogenous mixture

Solute

• what is being dissolved

Solvent

• what is doing the dissolving

Solubility

• The amount of a substance that will dissolve in a given amount of water ( measured of g/100 ml of H2O)

Aqueous Solution

• water solution (whenever water is solvent)

Dissolving

When dissolving, solutes may or may not form ions

• if it forms ions, its an electrolyte

Solvate

Dissolve = solvate = dissociate

Dissociation

• act of solvating

• When an ionic substance dissolves in water, the solvent pulls the individual ions from the crystal and solvates them

• Written as a reaction (NaCl (s) → Na^+ (aq) + Cl^+ (aq)

Electrostatic attraction/force

• force that makes up ionic bonds

Electrolyte

• an anion that is free to move in solution

Strong electrolytes

• substance that completely ionize when dissolved in water

• Conducts electricity well

Weak Electrolytes

• a substance that partially ionizes when dissolved in water

• Conducts electricity slightly

Nonelectrolytes

• A substance that does not ionize when dissolved in water

• Nonconductive

• Molecular compounds, etc

Strong Electrolytes

• strong acids

• Strong bases

• Ionic compounds

Strong acids

• dissociate completely to produce H+ in solution

So: H2SO4

I: HI

Brought: HBr

No: HNO3

Clean: HCl

Clothes: HClO4

Strong Bases

• React completely with water to give OH- ions

• Group 1 hydroxides, Ca(OH)2, Ba(OH)2, Sr(OH)2

Weak Electrolytes

• weak acids

• Weak bases

• Nonelectrolytes (molecular compounds, etc.)

Molarity definiton & formula

• (M)

• Moles of solute per volume of solution in liters

• M = moles of solute/liters of solution

Stock

• solutions stored in concentrated form, meaning that there is a relatively large ratio of solute to solvent (ex. x > 5.0 M)

Dilute

• Relatively small ratio of solute to solvent (ex. X <0.01 M)

Dilution

• adding more solvent to a solution of known concentration, often a concentrated stock solution

• Higher → lower concentration

Dilution formula

M1 *V1 = M2* V2

Precipitation Reaction

• Reaction in which dissolved substances react to form one (or more) solid products.

• Many involve exchange of ions between ionic compounds in aqueous solution and are often double replacement reactions

• Substances that precipitate are insoluble

Full ionic equation

• Split equation into ions, including spectator ions

Net ionic equation

• Exclude spectator ions

• Full ionic equation - spectator ions

Acid-base reaction

• reaction in which a hydrogen ion, H+ (a proton) is transferred from one chemical species to another.

Acid and base in acid-base definition

• Acid = proton donor (H+)

• Base = proton acceptor (usually OH-)

Titration

• delivery of a measure volume of a solution of a known concentration (the titrant) into a solution containing the substance being analyzed (the analyte)

Equivalence point titration

• enough titrant added to react exactly with the analyte

Endpoint titration

• the indicator changes color to tel that the equivalence point has been reached and surpassed.

• Slightly if done correctly

REDOX reaction

• Reaction in which one or more elements involved undergo a change in citation number (transfer of electrons)

• Transfer may or may not occur to form ions

• Includes oxidation and reduction

Oxidation

• increase in oxidation state (loss of electrons)

• Reducing agent

Reduction

• Decrease in oxidation state (gain of electrons)

• Oxidizing agent

Limiting reagent??

Oxidation number

• or oxidation state

• The charge the atoms of an element in a compound would possess if the compound was ionic

Combustion reactions

• type of REDOX reaction

• Reluctant (fuel) and oxidant (often O2) reaction to produce heat.

Single displacement ( Replacement ) reaction

• redox reaction in which an ion in solution is displaced (or replaced) via the oxidation of a metallic element)

Rules for Assigning Oxidation States

1. All compounds must be neutral

2. Oxidation state of an atom in an element = 0

3. Oxidation state of a monatomic ion = charge of the ion

4. Oxygen = -2 in covalent compounds (except in peroxides where -1

5. Hydrogen = +1 in covalent compounds

6. Fluorine = -1 in compounds

7. Sum of oxidation sates = 0 in compounds

8. Sum of oxidation states = charge of the ion in ions

Redox Titration

• done in acidic environment

• Perform using oxidized and reducing agents to find the concentration of an substance that undergoes oxidation

• One common agent = potassium permanganate

Synthesis Chemical Reactions

• a compound is made from simpler materials

• C (s) + O2 (g) → CO2 (g)

Decomposition Reaction

• a compound is broken down into simpler compounds, or all the way down to the element that make it up

• CaCO3 (s) → CaO (s) + CO2 (g)

Combustion Reaction

• a compound containing carbon and hydrogen ( and sometimes oxygen) combines with oxygen gas to produce carbon dioxide and water.

• CH4 (g) + O2 (g) → CO2 (g) + H2O (g)

Single Replacement Reaction

• one element that starts out by itself replaces another element in a compound, kicking it out

• Cu (s) + AgNO3 (aq) → Ag (s) + Cu(NO3)2 (aq)

Double Replacement Reaction

• the positive and negative ions in two compounds switch places

• BaCl2 (aq) + NaSO4 (aq) → BaSO4 (s) + NaCl (aq)