Disproportionation Reactions
A disproportionation reaction is one where an element in a substance undergoes oxidation and reduction simultaneously to give two products
Isotopes
Isotopes are atoms of the same element having the same atomic number but different nucleon number
Electronegativity
Electronegativity of an atom is a measure of its ability to attract the shared pairs of electrons in a covalent bond
Metallic Bond
Metallic bonds are strong forces of attraction between metal cations and the sea of delocalized electrons in the giant metallic lattice structure
Ionic Bond
Ionic bonds are strong electrostatic forces of attraction between cations and anions in the giant ionic structure
Covalent Bond
Covalent bonds are strong electrostatic forces of attraction between the nuclei of atoms and their shared pair of electrons.
Standard Enthalpy Change of Reaction (ΔHr⊖)
Standard enthalpy change of reaction is the energy change when molar quantities of reactants as stated in the thermochemical equation react together under standard conditions
Standard Enthalpy Change of Neutralisation (ΔHn⊖)
Standard enthalphy change of neutralisation is the energy evolved when one mole of water is formed during neutralisation of an acid and an alkali under standard conditions
Standard Enthalpy Change of Combustion (ΔHc⊖)
Standard enthalpy change of combustion is the energy evolved when one mole of a compound is burnt in excess oxygen under standard conditions
Standard Enthalpy Change of Atomisation of an Element (ΔHatom⊖)
Standard enthalpy change of atomisation of an element is the energy absorbed when one mole of gaseous atoms is formed from its elements under standard conditions
Standard Enthalpy Change of Atomisation of a Compound (ΔHatom⊖)
Standard enthalpy change of atomisation of a compound is the energy absorbed when one mole of a compound is converted to its constituent gaseous atoms under standard conditions
Bond Energy
Bond energy is the energy needed to break one mole of covalent bonds between two atoms in the gaseous state under standard conditions
1st Ionisation Energy
The first ionisation energy of an element is the amount of energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of singly-charged gaseous cationsX (g) --> X^+ (g) + e 🔺H= 1st I.E
2nd Ionisation Energy
The second ionisation energy of an element is the amount of energy required to remove one mole of electrons from one mole of singly-charged gaseous cations to form one mole of doubly-charged gaseous cationsX^+ (g) --> X^2+ (g) + e 🔺H= 2nd I.E
1st Electron Affinity
The first electron affinity of an element is the energy evolved when one mole of electrons is added to one mole of gaseous atoms to form one mole of singly-charged gaseous anions
Standard Lattice Energy
Standard lattice energy is the energy evolved when one mole of a compound is formed from its constituent gaseous ions
Standard Enthalpy Change of Hydration (ΔHhyd⊖)
Standard enthalpy change of hydration is the energy evolved when one mole of gaseous ions is surrounded by water molecules, forming a solution at infinite dilution under standard conditions
Standard Enthalpy Change of Solution (ΔHsol⊖)
Standard enthalpy change of solution is the energy change when one mole of substance is dissolved by a solvent such that further dilution produces no more energy change
Standard Enthalpy Change of Formation (ΔHf⊖)
Standard enthalpy change of formation is the energy change when one mole of a compound is formed from its constituent elements in their standard states under standard conditions
Entropy
Entropy is a measure of the randomness or disorder of a system
Dynamic Equilibrium
In a reversible system, dynamic equilibrium occurs when the rates of the forward and backward reactions are the same. There is no net change in the concentration of the reactants and products
Degree of Dissociation
The degree of dissociation is the fraction of the amount of a substance dissociated at equilibrium
Le Chatelier's Principle
Le Chatelier's Principle states that when a stress is applied to a reversible system at equilibrium, the system will react to reduce the stress
Rate of Reaction
The rate of a chemical reaction is defined as the change in concentration of reactant or product with time
Rate Equation
The rate equation is an experimentally determined equation that links the rate of a reaction to the concentration of each reactants and/or catalyst raised to a specific power
Order of Reaction
The order of reaction with respect to a given reactant/catalyst is the power to which the concentration of that reactant/catalyst is raised in the experimentally determined rate equation
Half-Life
Half-life of a reaction is defined as the time taken for the concentration of a reactant to reduce to half of its initial value
Rate Constant (k)
Rate constant is the proportionality constant in the rate equation
Activation Energy (Ea)
The activation energy is the minimum energy which the colliding molecules must possess before a collision will result in a reaction
Catalyst
A catalyst is a substance that alters the rate of a chemicial reaction without itself undergoing permanent chemical change
Acid [Bronsted-Lowry Theory]
Acids are proton (H^+) donor
Base [Bronsted-Lowry Theory]
Bases are proton (H^+) acceptors
Strong Acids (E.G: HCl)
Strong acids are acids that completely ionise in aqueous solutions to produce H^+ ions
Strong Base (E.G: KOH)
Strong bases are bases that completely ionise in aqueous solutions to form OH^- ions
pH Scale
pH is the negative logarithm to the base ten of the hydrogen ion concentrationpH=-lg [H^+]
Buffer Solution
It is a solution that is able to maintain a fairly constant pH when a small amount of acid or base is added
Solubility Product (Ksp)
The solubility product of a sparingly soluble salt is the product of the ion concentrations of a saturated solution raised to the powers equal to the stoichiometric coefficient in the balanced equation
Solubility
It is the maximum concentration of solute that can be dissolved in a given amount of a particular solvent at a specified temperature
Ionic Product
Ionic product is the product of the ion concentrations of a salt raised to the appropriate powers
Common Ion Effect
The common ion effect refers to the lowering of the solubility of an ionic compound due to the addition of a common ion
Standard Electrode Potential
The standard electrode potential of a half-cell is the potential difference between the electrode of the half-cell and the standard hydrogen electrode measured under standard conditions
Standard Cell Potential (E⊖cell)
The standard cell potential is the maximum potential difference between 2 electrodes of an electrochemical cell measured under standard conditions
Transition Elements
A transition element is a d-block element that can form one or more stable ions with a partially filled d-subshell
Complex Ion
A complex ion is a species that contains a central metal atom/ion surrounded by molecules or anions known as ligands which forms coordinate bonds to the metal centre
Ligand
A ligand is a molecule or anion with at least one pair of electrons that it can use to form a coordinate bond to the central metal atom or ion in a complex ion
Coordinate Number
Coordinate number indicates the number of coordinate bonds around the central metal atom or ion in the complex
Hess law
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