Studied by 6 people
the mole
the SI unit for amount of substance
molar mass
the mass in grams of one mole of that substance
solution
a homogenous mixture of solute and solvent
solute
the substance that is dissolved in the solution
solvent
the substance in which another substance is dissolved, forming a solution
concentration
the amount of solute per unit volume of solution
yield
a measure of the extent of a reaction, generally measured by comparing the amount of product against the amount of product that is possible
intramolecular bond
a bond which occurs between atoms within molecules
covalent bond
the sharing of at least one pair of electrons by two non-metal atoms
non-polar covalent (pure covalent)
an equal sharing of electrons
polar covalent
unequal sharing of electrons leading to a dipole forming (as a result of electronegativity difference)
electronegativity
a measure of the tendency of an atom to attract a bonding pair of electrons
ionic bond
a transfer of electrons and subsequent electrostatic attraction
metallic bonding
being between a positive kernel and a sea of delocalised electrons
intermolecular force
a force of attraction between molecules, ions, or atoms of noble gases
heat of reaction (ΔH)
the net change of chemical potential energy of the system
exothermic reactions
reactions which transform chemical potential energy into thermal energy
endothermic reactions
reactions which transform thermal energy into chemical potential energy
activation energy
the minimum amount of energy required to start a chemical reaction
activated complex
A high energy, unstable, temporary transition state between the reactants and the products
reaction rate
the change in concentration per unit time of either a reactant or product
catalyst
a substance that increases the rate of the reaction but remains unchanged at the end of the reaction
an acid
a proton donor
a base
a proton acceptor
ionisation
the reaction of a molecular substance with water to produce ions
strong acid
an acid that ionises completely in an aqueous solution
weak acid
an acid that only ionises partially in an aqueous solution
dissociation
the splitting of an ionic compound into it's ions
strong base
a base that dissociates completely in an aqueous solution
weak base
a base that only dissociates/ionises partially in an aqueous solution
amphoteric substances
a substance that can act as either an acid or a base
Kw for water at 25°C
Kw = [H3O+][OH-]
pH scale
the measure of hydronium ion concentration in water at 25°C
a salt
a substance in which the hydrogen of an acid has been replaced by a cation
hydrolysis of a salt
a reaction of an ion (from a salt) with water
neutralisation
the point where an acid and base have reacted so neither is in excess
a standrad solution
a solution of known concentration
redox reaction
A reaction involving the transfer of electrons
oxidation
the loss of electrons
reduction
the gain of electrons
oxidising agent
a substance that accepts electrons
reducing agent
a substance that donates electrons
anode
the electrode where oxidation takes place
cathode
the electrode where reduction takes place
electrolyte
a substance that can conduct electricity by forming free ions when molten or dissolved in solution
hydrocarbon
a compound containing only carbon and hydrogen atoms
saturated compound
a compound in which all of the bonds between carbon atoms are single bonds
unsaturated compound
a compound in which there is at least one double and/or triple bond between carbon atoms
functional group
an atom or a group of atoms that form the centre of chemical activity in the molecule
homologous series
A series of similar compounds which have the same functional group and have the same general formula, in which each member differs from the previous one by a single CH₂ unit
structural isomers
compounds having the same molecular formula but different structural formulae
closed system
one in which mass is conserved inside the system but energy can enter or leave the system freely
open system
one in which both energy and matter can be exchanged between the system and its surroundings
le châtelier’s principle
when an external stress is is applied to system in dynamic equilibrium, the equilibrium point will change in such a way as to counteract the stress
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