[NOTES/VOCAB] Chapter 5: Gases and the Kinetic-Molecular Theory Flashcards
Uneven Charge Distribution
Covalent bond sharing of electrons are not always distributed evenly due to the two nuclei having different molar masses
- creates a polar bond, on a ball-and-stick arrow model, it should be draw with “polar arrows” pointing to the negative pole
Bent Molecular Shape
ex. sequence of H-O-H atoms in water are not linear, but instead have a bent bond angle of 104.5 degrees
Molecular Polarity
Combination of polar bonds and bent shape makes a certain compounds, molecular molecules where one region of the molecule has a higher electron density (due to stronger pull) than the other ones
Replacement of Charge Attractions
Ionic compounds dissolve, water can separate the ions in an ionic compound by replacing these attractions with others between several water molecules and each ion
- soluble ionic compounds: the attractions between each type of ion and several water molecules outweigh the attractions between the ions themselves
- insoluble ionic compounds: the attraction between the cations and anions is greater than the attraction between the ions and water
Solvated
Surrounded closely by solvent molecules when ions separate (dissociate) and then move randomly in the solution
Electrical Conductivity
A measurement of how easily a material allows electric current to flow through it
- when ionic compounds dissolve, the conductivity increases dramatically
Electrolyte
A substance that conducts a current when dissolved in water is an electrolyte
Nonelectrolytes
Aqueous solutions do not conduct an electrical current
Concentration
The quantity of solute dissolved in a given quantity of solution (or of solvent)
Molarity (M)
The most common unit of concentration
- expresses the concentration in units of moles of solute per liter of solution
- M = moles of solute / liters of solution
- molarity can be used as a conversion factor
Precipitation Reaction
Two soluble ionic compounds react to form an insoluble product, a precipitate
- the key is the formation of an insoluble product through the net removal of ions from solution
Molecular Equation
Shows all the reactants and products as if they were intact, undissociated compounds
Total Ionic Equation
Accurate; shows all the soluble ionic substance as they actually exist in solution, where they are dissociated into ions
Spectator Ions
Not involved in the actual chemical change, but are present as part of the reactants
Net Ionic Equation
Eliminates the spectator ions and shows only the actual chemical change
Metathesis Reactions
Where the reactant ions change partners, double0displacement reactions
Acid-base Reaction (Neutralization Reaction)
When an acid reacts with a base
- strong acids and bases are strong electrolytes
Acid
A substance that produces H+ ions when dissolved in water
- strong acids: ionize completely in a solution
- weak acids: dissociates very little
Base
A substance that produces OH- ions when dissolved in water
- bases are categorized as strong or weak depending on the extent to which they produce hydroxide ions
Oxidation-Reduction (Redox) Reaction
Net movement of electrons from one reactant to another
- movement occurs from the reactant (or atom in the reactant) with less attraction for electrons to the reactant (or atom) with more attraction for electrons
Oxidizing Agent
Species doing the oxidizing (causing the electron loss)
Reducing Agent
The species doing the reducing (causing the electron gain)
Oxidation Number (O.N.)
The charge the atom would have if its electrons were transferred completely, not shared
- each element in a binary ionic compound has a full charge because the atom transferred its electrons, and so the oxidation number equals the ionic charge
- each element in a covalent compound (or in a polyatomic ion) has a partial charge because the electrons shifted away from one atom and toward the other
- if an atom has a higher (more positive/negative) ON in the product, than it had in the reactant, the reactant that contains that atom was oxidized (lost electrons) and is the reducing agent, thus oxidation is shown by an decrease in ON [viceversa]
Combination of Two Elements REDOX
X+Y=>Z
1) Metal and nonmetal form an ionic compound, the petal is the reducing agent and the nonmetal is the oxidizing agent
2) Two nonmetals form a covalent compound
- many nonmetal oxides react with additional O2 to form “higher” oxides (those with more O atoms in each molecule
- ex. many nonmetal halides combine with additional halogen to form “higher” halides
Decomposition REDOX
Z=>X+Y
1) Thermal decomposition, when energy is absorbed as heat
2) Electrolytic decomposition, within the electrolysis process in which a compound absorbs electrical energy and decomposes into into its elements
Displacement REDOX
AB+CD=>AD+CD
The number of substances on the two sides remain the same, but atoms (or ions) exchange places
1) Double-displacement (metathesis) reactions [precipitation and acid-base reactions], atoms or ions of two compounds exchange places; NOT REDOX
2) Single-displacement reactions, one substance is an element; all single displacement reactions are redox processes
X+YZ=XZ+Y
Dynamic Equilibrium
No further changes appear in the amounts of reactants or products
- macroscopic POV: reaction is static
- molecular POV: reaction is dynamic
