Definitions Flashcards
Primary standard
A substance that can be obtained in a stable, pure and soluble solid form so that it can be weighed out and dissolved in water to give a solution of accurately known concentration
Standard solution
A solution whose concentration is accurately known
Relative molecular mass
Of a compound is the average mass of 1 molecule of that compound compared with 1/12th of the mass of 1 atom if the carbon 12 isotope
One mole
Of a substance is the amount of that substance that contains 6 x 10^23 particles of that substance
Volatile liquid
One with low boiling point
Atomic radius \ covalent radius
Of an atom is defined as half the distance between the nuclei of 2 atoms of the same element that are joined together by a single covalent bond
Heterogeneous catalysis
In which the reactants and the catalyst are in different phases I.e boundary between them
Atomic number
Of an atom is the number of protons in nucleus of that atom
Auto ignition
Is premature ignition of the petrol- air mixture before normal ignition of the mixture by a spark takes place
Octane number
Of a fuel is a measure of the tendency of the fuel to resist knocking
Homologous series
A series of compounds of similar chemical properties
Showing gradations in physical properties
Having a general formula for its members
Each member having a similar method of preparation
Each member differing from the previous member by a CH2 unit
Le chateliers principle
States that if a stress is applied to a system at equilibrium, the system re-adjusts to relieve this stress applied
Chemical equilibrium
Is a state of dynamic balance in a reversible reaction where the rate of the forward reaction is the same as the rate of the backward reaction
Conjugate acid base pair
A pair consisting of an acid and a base that differ by one proton
Weak acid - bronsted lowry
Poor proton donor
