Definitions Flashcards
(31 cards)
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
pH
-log to base 10 [H+]
Rate of reaction
The change in concentration per unit time of any 1 reactant or product
Activation energy
Minimum energy that colliding particles must have for a reaction to occur I.e. minimum energy required for effective collisions between particles to occur
Effective collision
One that results in the formation of products
Aromatic compound
Compound that contains a benzene ring structure in their molecules
Aliphatic compound
Am organic compound that consists of open chains of carbon atoms and closed chain compounds (rings) that resemble them in their chemical properties
Unsaturated
Compound in which there are one or more double or triple bonds between the atoms in the molecules
Test for unsaturation
KMnO4 - purple to colourless
Bromine water - red to colourless
Anion aqueous solution = carbonate and hydrogencarbonate
Add dilute HCL
Gas produced that turns limewater milky
