Chemistry Flashcards
.Light
Energy of an electromagnetic wave
Constants
Speed of Light:
Light
Rydberg equation
Compounds and Stoichiometry
Equation for moles
Compounds and Stoichiometry
Equation for Gram Equivalent Weight (GEW)
For acids: The number of replaceable hydrogen ions (H⁺) per molecule.
For bases: The number of hydroxide ions (OH⁻) the base can donate.
For salts: The total charge of cations or anions.
For redox reactions: The number of electrons lost or gained per molecule or ion.
Compounds and Stoichiometry
Equation for Equivalents
Compounds and Stoichiometry
Equation for Molarity
Compounds and Stoichiometry
Equation for Percent Compostion
Mass of element in compound: The total mass of a specific element in the compound, often calculated by multiplying the element’s atomic mass by the number of its atoms in the molecular formula.
Total molar mass of compound: The sum of the molar masses of all elements in the compound.
Compounds and Stoichiometry
Equation for Percent Yield
Actual Yield: The amount of product actually obtained from the experiment or reaction, measured in grams, moles, or other units.
Theoretical Yield: The maximum possible amount of product that could be formed based on stoichiometric calculations, assuming perfect reaction conditions with no losses.
Chemical Bonding
What’s the formula to calculate the force between the atoms in an ionic bond
F ∝ q1*q2 / r2
q1 and q2 = charge magnitude of the ions
r = distance between the ions
Chemical Bonding
What is the electrostatic energy (Ees) of an ionic bond?
Ees ∝ q1*q2 / r
This holds for all charged particles, and thus can be applied to calculate energy between the atoms in an ionic bond.
q1 and q2 = charge magnitude of the atom
r = distanc
Equation to calculate the rate constant of a reaction: Arrhenius Equation
Avogadro’s number
Used to determine the equilibrium concentrations of different reagents in a reversible reaction (ex. aA + bB ⇌ cC + dD)
Molality
Formula for the concentration of a solution in molality
Molarity
Formula for the concentration of a solution in molarity.
Formula for the reaction quotient for the equilibrium reaction aA + bB ⇌ cC + dD.
Used to compare reaction conditions to equilibrium conditions by comparing Qc to Keq. Qc = Keqat equilibrium.
Relationship of K and Q
Used to determine which direction a reaction will shift to reach equilibrium.
If K > Q, a reaction will proceed forward, converting reactants into products.
If K < Q, the reaction will proceed in the reverse direction, converting products into reactants.
First law of thermodynamics
ΔU = Q - W
ΔU - change in internal energy of the system
Q - heat entering the system
W - work done by the system
R Gas constant
1 atm equivalents
Ideal Gas Law
P = pressure in Pa or atm
V = volume in m3
n = moles of gas
R = ideal gas constant = 8.314 J mol-1 K-1 (if P in Pa) = 0.0821 L atm mol-1 K-1 (if P in atm)
T = temperature in Kelvin
Combines Boyle’s law, Charles’ law, and Avogadro’s law.
Used to determine pressure, volume, moles, or temperature of a gas
Density of Gas
Combined Gas Law
Avogadro’s Law
Used to calculate the amount in moles or volume of a gas in response to
volume of a gas and moles are proportional at constant temp & pressure.
Boyle’s Law
(Used to calculate the resulting pressure or volume of a gas in response to a change in either.)
P1 = initial pressure in atm (most common)
V1 = initial volume in L (most common)
P2 = final pressure in same units as P1
V2 = final volume in same units as V1
States that the pressure and volume of a gas are inversely proportional at constant temperature.
Charles’ Law
(Used to calculate the resultant volume or temperature of a gas in response to a change in either.)
States that the volume and temperature of a gas are directly proportiona
Gay-Lussac’s Law
(Used to calculate the resultant pressure or temperature of a gas in response to a change in either.)
Dalton’s Law of Partial Pressures
(Used to calculate the total pressure of a sample of multiple gases or the partial pressure of one gas in a sample of multiple gases.)
States that the total pressure of a sample of multiple gases is equal to the sum of the partial pressures of the individual gases.
Kinetic Energy
Formula for the kinetic energy of a moving object
KE = kinetic energy in J
m = mass in kg
v = speed in m/s
Raoult’s Law (AKA Daltons Partial Pressure)
(Used to calculate the vapor pressure of solutions or the partial vapor pressures of many liquids in a mixture)
States that the vapor pressure of a volatile liquid in a solution is scaled by its mole fraction in the mixture
PA = vapor pressure of solution in atm (most common)
XA = mole fraction of the solvent unitless
P°A = vapor pressure of solvent in same units as PA
Van der Waals Equation of State
(Used to compare real values of pressure to those calculated by the Ideal Gas Law.)
Describes the pressure of real gases, in contrast to ideal gases, by considering the molar volume (constant b) and intermolecular interactions (constant a) of a given gas.
P = pressure in Pa (N/m2)
n = amount of gas in moles
R = ideal gas constant = 8.314 J mol-1 K-1
T = temperature in Kelvin
V = molar volume in m3
b = volume occupied by individual gas molecules in m3/mol
a = average attraction between gas molecules in Pa m6 mol-2
Average Kinetic Energy of Gas
(Used to calculate average kinetic energy or temperature when the other is known.)
States that the temperature of a gas is directly proportional to the average kinetic energy of its particles.
KEavg = average kinetic energy of a gas particle in J
kB = Boltzmann constant = 1.38 x 10-23 J/K
T = temperature in Kelvin
Molality: Formula for the concentration of a solution in molality.
Raoult’s Law: Used to calculate the vapor pressure of solutions or the partial vapor pressures of many liquids in a mixture.
PA = vapor pressure of solution in atm (most common)
XA = mole fraction of the solvent unitless
P°A = vapor pressure of solvent in same units as PA
States that the vapor pressure of a volatile liquid in a solution is scaled by its mole fraction in the mixture.
Freezing Point Depression
𝛥Tf = freezing point depression in Kelvin or ℃
i = van’t Hoff factor of solute unitless
Kf = cryoscopic constant in K kg mol-1
m = molality of solution in mol/kg
Describes the degree of freezing point depression of a liquid with a given concentration of solutes.
Formula for the reaction quotient for the equilibrium reaction aA + bB ⇌ cC + dD.
Qc = reaction quotient unitless
[A] = concentration of reactant A in molarity
[B] = concentration of reactant B in molarity
[C] = concentration of product C in molarity
[D] = concentration of product D in molarity
a = coefficient of reactant A unitless
b = coefficient of reactant B unitless
c = coefficient of product C unitless
d = coefficient of product D unitless
Used to compare reaction conditions to equilibrium conditions by comparing Qc to Keq. Qc = Keqat equilibrium.
Dilution Formula: Used to calculate the amount of solvent required for the desired dilution or to calculate resultant concentration after dilution with a known amount of solvent
Mi = initial concentration in molarity
Vi = initial volume in L
Mf = final concentration in molarity
Vf = final volume in L
Formula for the equilibrium constant for the reaction aA + bB ⇌ cC + dD.
Keq = equilibrium constant unitless
[A] = equilibrium concentration of reactant A in molarity
[B] = equilibrium concentration of reactant B in molarity
[C] = equilibrium concentration of product C in molarity
[D] = equilibrium concentration of product D in molarity
a = coefficient of reactant A unitless
b = coefficient of reactant B unitless
c = coefficient of product C unitless
d = coefficient of product D unitless
Used to determine the equilibrium concentrations of different reagents in a reversible reaction.
Molarity: Formula for the concentration of a solution in molarity.
Boiling Point Elevation: Describes the degree of boiling point elevation of a liquid with a given concentration of solutes.
𝛥Tb = boiling point elevation in Kelvin or ℃
i = van’t Hoff factor of solute unitless
Kb = ebullioscopic constant in K kg mol-1
m = molality of solution in mol/kg
Osmotic Pressure: Used to estimate the ability of a solution to accept solvent by osmosis.
𝛱 = osmotic pressure in pascals or atm
i = van’t Hoff factor unitless
M = concentration of solution in molarity
R = ideal gas constant = 8.314 J mol-1 K-1 (if 𝛱 in Pa) = 0.0821 L atm mol-1 K-1 (if 𝛱 in atm)
T = temperature in Kelvin
Formula for the osmotic pressure, the minimum pressure required to prevent a solvent from moving across a semipermeable membrane.
Percent Composition by Mass
mass of solute in grams (most common)
mass of solution in same units as mass of solute
Acid Dissociation Constant
Ka = acid dissociation constant unitless
[H3O+] = concentration of hydronium ions in molarity
[A‒] = concentration of conjugate base in molarity
[HA] = concentration of acid in molarity
Used to determine the concentrations of species in an aqueous acid at equilibrium.
Henderson-Hasselbach Equation: Used to calculate the pH of buffers.
pH = pH of buffer unitless
pKa = pKa of acid unitless
[A‒] = concentration of conjugate base in molarity
[HA‒] = concentration of acid in molarity
Equation relating the pH of an acid buffer to the ratio acid to conjugate base in solution.
Nernst Equation: Equation for the cell potential of an electrochemical cell at non-standard conditions.
Ecell = non-standard cell potential
E°cell = standard cell potential
R = gas constant = 8.314 J mol-1 K-1
T = temperature in Kelvin
n = number of moles of electrons transferred in reaction unitless
F = Faraday constant = 96485 J V-1 mol-1
Q = reaction quotient unitless
pH Formula
pH unitless
[H+] = concentration of hydrogen ions in molarity
pOH Formula
pOH unitless
[OH‒] = concentration of hydroxide ions in molarity
Henderson-Hasselbach Equation: Used to calculate the pOH of buffers.
pOH = pOH of buffer unitless
pKb = pKb of base unitless
[HB+] = concentration of conjugate acid in molarity
[B] = concentration of base in molarity
Equation relating the pOH of a base buffer to the ratio between base and conjugate acid in solution.
Relationship of Ka and Kb: Used to calculate the Ka of an acid when the Kb of its conjugate base is known, or to calculate the Kb of a base when the Ka of its conjugate acid is known
Cell Potential: Formula for the cell potential of an electrochemical cell with known half-reaction standard reduction potentials.
E°cell = cell potential in V
E°cathode = standard reduction potential of the cathode in V
E°anode = standard reduction potential of the anode in V
Equivalence Point
Na = normality of acid in equivalents/L
Va = volume of acid in L
Nb = normality of base in equivalents/L
Vb = volume of base in L
Gibbs Free Energy of Cell: Describes the relationship between an electrochemical cell’s cell potential and the Gibbs free energy change of its redox reaction.
𝛥G° = Gibbs free energy change in J/mol
n = number of moles of electrons transferred in reaction unitless
F = Faraday constant = 96485 J V-1 mol-1
E°cell = cell potential in V
Gibbs Free Energy of Cell: Describes the relationship between a reaction’s equilibrium constant and its Gibbs free energy change.
𝛥G° = Gibbs free energy change in J/mol
R = gas constant = 8.314 J mol-1 K-1
T = temperature in Kelvin
Keq = equilibrium constant unitless
Gibbs Free Energy of Cell: Formula for the Gibbs free energy change of a reaction at non-standard conditions.
𝛥G = non-standard Gibbs free energy change in J/mol
𝛥G° = standard Gibbs free energy change in J/mol
R = gas constant = 8.314 J mol-1 K-1
T = temperature in Kelvin
Q = reaction quotient unitless
Autoionization Constant (Water): Used to calculate hydronium concentration or hydroxide concentration when the other is known
Kw = autoionization constant unitless
[H3O+] = concentration of hydronium ions in molarity
[OH‒] = concentration of hydroxide ions in molarity
States that the product of hydronium concentration and hydroxide concentration equal the autoionization constant, 10-14.
