General Chemistry Flashcards
Isoelectronic Series
Same number of electrons but different number of protons.
Anions: larger radius
Cations: smaller radius
Effective Nuclear Charge
amount of positive charge experienced by electrons.
Increases as you move right and up.
Ionization energy
Energy needed to remove an electron from an atom.
Increases as you move right and up.
2nd, 3rd, and 4th ionization energies are increasingly harder.
Exceptions: Group 2>13
Group 15 >16
Electron Affinity
Amount of energy released when an electron is added.
Increases as you move right and up; noble gases are zero.
Exceptions: Group 4A>5A
Electronegativity
Ability to draw electrons from other atoms.
Increases as you move right and up.
Principal Quantum Number
First number in QN, denoted by n.
Gives the main energy level of the electron; must be greater than or equal to 1.
Azimuthal Quantum Number
Second number in QN, denoted by L.
Describes the orbital shape.
Will be between zero and n-1.
L=0, 1, 2, and 3 are s, p, d, and f, respectively.
Magnetic Quantum Number
Third number in QN, denoted by ml.
Describes orbital orientation.
Will be between +L and -L.
Spin Quantum Number
4th number in QN, denoted by ms.
Describes angular momentum.
Will be either +1/2 or -1/2.
Pauli’s Exclusion Principle
No two electrons in the same atom can have the same Quantum Number.
Percent Composition
Mass of element in compound/Molar mass of molecule
Percent Yield
Actual Yield/Theoretical Yield x 100
Soluble Salts
Group 1 Cations
Acetate
NO3-
ClO4-
NH4+
Insoluble Salts
Ag+
Pb2+
Hg2+
OH-
S2-
CO3 2-
PO4 3-
Strong Acids
HCl
HBr
HI
HClO4
HClO3
H2SO4
HNO3
Strong Bases
Group 1 metal Hydroxides
Ba(OH)2
Sr(OH)2
Ca(OH)2
Molarity vs. Molality
Molarity: number of moles of solute per one liter of solution.
Molality: number of moles of solute per 1 kg of solvent.
Colligative Properties
Depend on concentration of solute molecules/ions, but not on identity of the solute.
Vapor pressure depression, boiling point elevation, freezing point depression, osmotic pressure.
Non-Colligative Properties
Depend on identity of solute and solvent.
Surface tension, color, viscosity, solubility, density.
Altitude Effects on Boiling Point
BP is when vapor pressure = atmospheric pressure.
At higher elevation, there is less atm pressure, so less vapor pressure is required to reach boiling point, so BP is lower.
Vice versa for lower elevation.
Boyle’s Law
Pressure and Volume are inversely proportional.
P1 V1 = P2 V2
Charles’s Law
Volume and Temperature are directly proportional.
V1/T1 = V2/T2
Avogadro’s Law
Volume and Moles are directly proportional.
V1/n1 = V2/n2
Gay-Lussac’s Law
Pressure and Temperature are directly proportional.
P1/T1 = P2/T2
Ideal Gases
Follow 5 Rules:
1) constant random motion
2) combined volume of particles is negligible.
3) particles exert no forces on one another.
4) gas molecule collisions are completely elastic (no IMF).
5) all gases have same avg KE at a given temp.
Gases are ideal at low pressure and high temperature.
Effusion
Confined gas escaping through a hole.
Lower molecular weight will effuse faster.
Phase Diagrams:
Triple Point
Critical Point
TP: where all lines meet; substance present in all three phases.
CP: gas and liquid phases are indistinguishable; supercritical fluid.
Phase Change Equation
q = mH
H = heat of fusion or vaporization.
Hess’s Law
Total enthalpy change for the reaction is the sum of all changes.
Entropy
Degree of disorder or randomness.
Higher entropy is favored because is lower in energy and more stable.
Laws of Thermodynamics
1: Energy can’t be created or destroyed.
2: Entropy of the universe is always increasing.
3: Entropy of a pure crystalline substance at 0 Kelvin is zero.
Exergonic vs. Endergonic
Ex: energy is released; G<0; spontaneous.
End: energy is absorbed; G>0; nonspontaneous.
Factors that Effect Reaction Rate
Increase T: increase k, increase rate.
Decrease Ea: increase k, increase rate.
Increasing [reactants]: no effect on k, increases rate.
Reactions:
Intermediate
Catalyst
I: product then reactant.
C: reactant then product, but not in overall reaction.
Acid and Base Definitions:
Arrhenius
Bronsted-Lowry
Lewis
A: acids produce H+ in aqueous solution; bases produce OH-.
BL: acids are proton donors, bases are proton acceptors.
L: acids are electron pair acceptors; bases are electron pair donors.
Calculating pH and pOH from concentration
pH = -log[H+]
pOH = -log[OH-]
Types of Salts Produced through Neutralization Reactions
Strong Acid + Strong Base = neutral salt.
Strong Acid + Weak Base = acidic salt.
Weak Acid + Strong Base = basic salt.
Making Acidic Buffers
Weak Acid + Salt (CB) 1:1
Weak Acid + Strong Base 2:1
Salt (CB) + Strong Acid 2:1
Making Alkaline Buffers
Weak Base + Salt (CA) 1:1
Weak Base + Strong Acid 2:1
Salt (CA) + Strong Base 2:1
Equivalence Point
Half Equivalence Point
EP: amount of titrant added is just enough to neutralize the analyte solution; steepest part of the curve.
N1V1 = N2V2
HEP: SA + WB or WA + SB. midpoint of the buffering/flat region.
pH=pKa.
Equivalence Points in Titrations:
Strong Bases
Strong Acids
When involving strong bases and weak acids, the EP will be greater than 7.
When involving strong acids, the EP will be less than 7.
When involving strong acids and strong bases, the EP will be 7.
Equilibrium Constant
Product concentrations over reactant concentrations.
Keq < 1: greater concentration of reactants at equilibrium.
Keq > 1: greater concentration of products at equilibrium.
Keq = 1: ratio of products and reactants is equal.
Reaction Quotient
Concentration of reactants and products at any point in the reaction.
Q< Keq: higher reactant concentration than at Eq, proceeds forward.
Q > Keq: higher product concentration than at Keq, proceeds in reverse.
Q = Keq: dynamic equilibrium
Compression and Expansion effects on reaction rates
Compression: shift to side with fewer gas molecules.
Expansion: shift to side with more gas molecules.
Solubility Product Constant
Describes extend to which an ionic compound dissolves in water.
Qsp < Ksp: unsaturated
Qsp = Ksp: saturated
Qsp > Ksp: supersaturated
Oxidizing Agents vs. Reducing Agents
OA: oxidizes other species, gets reduced.
Ex: O2, O3, H2SO4, halogens
RA: reduces other species, gets oxidized.
Ex: H2, Fe, Zn, Alkali metals
What happens at anode and cathode of electrochemical cells
Anode: oxidation
Cathode: reduction
An Ox and Red Cat
Electrons always flow from anode to cathode.
Galvanic/Voltaic Cells vs. Electrolytic Cells
G/V: (battery) spontaneous (G<0), converts chemical energy to electrical energy; - anode and +cathode; Ecell>0.
E: (charging battery) nonspontaneous (G>0), converts electrical energy to chemical energy; +anode and -cathode; Ecell<0.
Dissociation Constant of Water
Kw at room temperature is 1e-14.
For pure water, Ka = Kb.
Standard Temperature and Pressure
T: 273 K
P: 1 atm
Any 1 mole of gas will have a volume of 22.4 L.
What determines Specific Heat Capacity?
Strength of intermolecular forces.
Stronger IMF = higher SHC
Paramagnetic vs. Diamagnetic
P: elements with unpaired electrons; attracted to magnetic field.
D: elements with paired electrons; repelled by magnetic field.
O2: paramagnetic
N2: diamagnetic
F2: diamagnetic
