IB Chem HL

Molar Mass
The mass of one mole of any substance, expressed in grams per mole
Relative Atomic Mass

The average mass of an atom taking into account the relative abundances of all the naturally occurring isotopes of the element relative to one atom of C-12

Realative term so no units 

Relative Molecular Mass
The average mass of a molecule calculated by adding the relative atomic masses of its constituent atoms. Relative term so no units
Empirical Formula
The simplest whole number ratio of the atoms a compound contains
Molecular Formula
The actual number of atoms of each element present. A multiple of the empirical formula
The substance dissolved in a solvent in forming a solution
The liquid that dissolves another substance to form a solution
A homogeneous mixture of the solvent and the solute
The amount of solute in a known volume of solution expressed in mol/dm3
Mass Number
The total of protons plus neutrons in the nucleus of an atom
Atomic Number

The number of protons in an atoms nucleus

Equal to the number of electrons

Determines placement on periodic table 

Atoms of the same element with different numbers of neutrons
Continuous Spectrum
An unbroken spectrum of frequencies such as the spectrum of visible light
Line Spectrum
A broken spectrum of frequencies, showing only certain frequencies of visible light
The vertical column of elements on the periodic table of elements
The horizontal row of elements on the periodic table of elements
First Ionization Energy
The minimum energy required to remove one mole of electrons from a mole of gaseous atoms
The tendency to attract electrons
An ion or molecule that donates a pair of electrons to a metal atom or ion
Exothermic reaction

Releases heat to the surroundings Products stronger than reactants 


Endothermic Reaction

Absorbs heat from the surroundings Products weaker than the reactants 


Standard Enthalpy Change of Reaction
The heat transferred in a reaction carried out under standard conditions
Average Bond Enthalpy
The energy required to break a mole of covalent bonds in a reactant, all reactants and products being in their gaseous states
Standard State
The most stable state of an element under the specified conditions
Standard Enthalpy Change of Formation
The enthalpy change on the formation of one mole of a compound from its elements in their standard states under specified conditions
Standard Enthalpy Change of Combustion
The enthalpy change on the complete combustion of one mole of a compound in its standard state in excess oxygen under standard conditions
Lattice Enthalpy
The enthalpy change that occurs on the formation of one mole of ionic compound from its isolated ions in their gaseous state
Electron Affinity
The energy change occurring when a gaseous atom gains and electron to form a negative ion
Rate of reaction
The increase in concentration of products per unit time. Expressed in Mol/Dm3S
Activation Energy
The minimum energy required for a chemical reaction to take place
Rate Constant

K in the rate equation


Order of Reaction
With respect to a reactant is the power to which its concentration is raised in the rate equation
Bronsted-Lowry Acids and Bases
Bronsted-Lowry acid= Proton donor Bronsted-Lowry base=Proton acceptor
Lewis Acids and Bases
Lewis Acid=Electron Pair acceptor
Lewis Base= Electron Pair Donor
Strong and Weak Acids and Bases
Strong acids and bases are almost completely dissociated Weak acids and bases are only partially dissociated
pH pOH pKw







Oxidation and reduction
Oxidation is the loss of electrons and reduction is the gain of electrons
Oxidizing Agent and Reducing Agent
Oxidising agents accept electrons and get reduced reducing agents donate elctrons and get oxidised
Standard Electrode Potential
The electrode potential relative to a hydrogen half cell measured under standard conditions
Precision and Accuracy
Precise Measurements have small random errors and accurate measurements have small systematic errors