[NOTES/VOCAB] Chapter 5: Gases and the Kinetic-Molecular Theory

Question 1

Uneven Charge Distribution

Answer 1

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

Question 2

Bent Molecular Shape

Answer 2

ex. sequence of H-O-H atoms in water are not linear, but instead have a bent bond angle of 104.5 degrees

Question 3

Molecular Polarity

Answer 3

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

Question 4

Replacement of Charge Attractions

Answer 4

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

Question 5

Solvated

Answer 5

Surrounded closely by solvent molecules when ions separate (dissociate) and then move randomly in the solution

Question 6

Electrical Conductivity

Answer 6

A measurement of how easily a material allows electric current to flow through it
- when ionic compounds dissolve, the conductivity increases dramatically

Question 7

Electrolyte

Answer 7

A substance that conducts a current when dissolved in water is an electrolyte

Question 8

Nonelectrolytes

Answer 8

Aqueous solutions do not conduct an electrical current

Question 9

Concentration

Answer 9

The quantity of solute dissolved in a given quantity of solution (or of solvent)

Question 10

Molarity (M)

Answer 10

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

Question 11

Precipitation Reaction

Answer 11

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

Question 12

Molecular Equation

Answer 12

Shows all the reactants and products as if they were intact, undissociated compounds

Question 13

Total Ionic Equation

Answer 13

Accurate; shows all the soluble ionic substance as they actually exist in solution, where they are dissociated into ions

Question 14

Spectator Ions

Answer 14

Not involved in the actual chemical change, but are present as part of the reactants

Question 15

Net Ionic Equation

Answer 15

Eliminates the spectator ions and shows only the actual chemical change

Question 16

Metathesis Reactions

Answer 16

Where the reactant ions change partners, double0displacement reactions

Question 17

Acid-base Reaction (Neutralization Reaction)

Answer 17

When an acid reacts with a base
- strong acids and bases are strong electrolytes

Question 18

Acid

Answer 18

A substance that produces H+ ions when dissolved in water
- strong acids: ionize completely in a solution
- weak acids: dissociates very little

Question 19

Base

Answer 19

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

Question 20

Oxidation-Reduction (Redox) Reaction

Answer 20

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

Question 21

Oxidizing Agent

Answer 21

Species doing the oxidizing (causing the electron loss)

Question 22

Reducing Agent

Answer 22

The species doing the reducing (causing the electron gain)

Question 23

Oxidation Number (O.N.)

Answer 23

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]

Question 24

Combination of Two Elements REDOX

Answer 24

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

Question 25

Decomposition REDOX

Answer 25

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

Question 26

Displacement REDOX

Answer 26

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

Question 27

Dynamic Equilibrium

Answer 27

No further changes appear in the amounts of reactants or products
- macroscopic POV: reaction is static
- molecular POV: reaction is dynamic