Year 2 Flashcards
(38 cards)
Rate of reaction
Rate of change of concentration of reactants or products.
Units are mol dm⁻³ s⁻¹.
Order of reaction
Power of reactant’s concentration in the rate equation.
Rate constant
The constant of proportionality, k, in the rate equation.
Half-life
The time for the concentration of a reactant to fall to half its original value.
Rate determining step
The slowest step in a reaction mechanism.
Acid (Bronsted-Lowry)
Proton donor.
Base (Bronsted-Lowry)
Proton acceptor.
Strong acid or base
Fully ionised (or dissociated) in water.
Weak acid or base
Partially ionised (or dissociated) in water.
Conjugate acid-base pair
Two species differing by H+ ions.
pH
pH = - log[H+] so [H+] = 10^-pH.
pKa
pKa = - log[Ka] so Ka = 10^-pKa.
Kw (ionic product of water)
Kw = [H+][OH-].
Ka (acid dissociation constant)
Ka = [H+][A-] / [HA].
Buffer solution
A solution that minimises change in pH.
Lattice Enthalpy
The enthalpy change when one mole of a solid ionic compound forms from its gaseous ions.
Example: Na+(g) + Cl-(g) → NaCl(s).
Enthalpy of Solution
Enthalpy change when one mole of an ionic solid is completely dissolved in water.
Example: NaCl(s) → Na+(aq) + Cl-(aq).
Enthalpy of Hydration
Enthalpy change when one mole of gaseous ions is completely dissolved in water.
Example: Na+(g) → Na+(aq) or Cl-(g) → Cl-(aq).
Standard Conditions
298K, 100KPa, 1.00 moldm⁻³.
What is a transition element?
A d-block element forming one or more stable ions with an incomplete subshell of d electrons.
What is a complex ion?
A central ion surrounded by ligands.
What is a ligand?
An ion or molecule with a lone pair of electrons able to form a dative covalent bond.
What is ligand substitution?
A reaction in which one ligand is substituted by another ligand.
What is the coordination number?
The number of lone pairs bonded to the central metal ion.
