Semester Exam Study Guide

Relationship between PT position and electronegativity difference

The greater the distance on the Periodic Table, the higher the electronegativity difference.

All polar bonds don't make polar molecules

False; Example:Carbon dioxide, where opposing polar bonds cancel out polarity.

Considerations for molecule polarity

Bond types, central atom's unbonded electrons, and symmetry of outside atoms.

Least and most polar bonds

Least - C-H, Most - H-F due to electronegativity values.

Steps for drawing Lewis Structures

List valence electrons, form single bonds, distribute electrons, adjust for octet rule violations.

Intermolecular forces strength order

London dispersion forces < Dipole-dipole forces < Hydrogen bonding.

Types of forces between atoms

Covalent bonds (nonmetals), ionic bonds (metal-nonmetal), metallic bonds (metals); Intramolecular force:Covalent bonds.

Strongest intermolecular forces state

Solids; Weakest:Gases.

Melting & boiling points relation to intermolecular forces

Higher forces lead to higher points.

Limiting reactant

Reactant fully consumed, limiting product formation.

Theoretical yield

Maximum product amount in complete reaction.

Determining limiting reactant

When given values for at least two reactants.

Example of a strong acid

HCl.

Organic acids strength

Weak.

Acid-base reaction identification

HI(aq) + KOH(aq) → KI(aq) + H2O(l); Neutralization reaction.

Dilution calculation

M1V1 = M2V2; Calculate new molarity after dilution.

pH calculation from solution

Dissolving HI to find [H3O+].

pOH calculation

For a solution of LiOH.

Oxidation-Reduction T-chart

Oxidation increases numbers, reduction decreases; Loss of electrons in oxidation, gain in reduction.

Common oxidation numbers assignment

N = -3, Ca = +2, Cl = -1, O = -2, F = -1, H = +1.

Oxidation numbers assignment in compounds

CO2 (C = +4, O = -2), Na2SO3 (Na = +1, S = +4, O = -2), N2 (N2 = 0), Na2SO4 (Na = +1, S = +6, O = -2), Cr2O72- (Cr = +6, O = -2).

Oxidation-Reduction identification

Mg oxidized (0 to +2), H reduced (+1 to 0), Cl remains at -1.

Non-redox reaction identification

Choose the equation not representing oxidation-reduction reactions.

Displacement reactions using the activity series

Elements displacing Sn2+ but displaced by Al3+:Iron, zinc, carbon.

Nuclear Decay

Spontaneous disintegration of a radionuclide with the emission of energetic particles or radiation, such as alpha or beta particles, or gamma rays.

Beta Decay

In beta decay, 0 is the mass number & -1 is the atomic number.

Alpha Decay

In alpha decay, the atomic # is 2, the mass # is 4, and there are 2 neutrons.

Temperature

The average kinetic energy of a substance/system.

Heat

The total kinetic energy of a substance/system.

Equilibrium

When the rate of the forward reaction is equal to the rate of the reverse reaction.

Equilibrium Constant (K)

Represents the concentration of products over the concentration of reactants.

Endothermic Process

The system absorbs energy from the surroundings; ∆H is positive for endothermic reactions.

Exothermic Process

The surroundings absorb energy from the system; ∆H is negative for exothermic reactions.

Equilibrium Expression

Omitted phases in equilibrium expressions are solids and liquids.

Factors Affecting Reaction Rate

High temperature, large surface area, increased concentration, and a catalyst together yield the fastest rate.