AS 2 - Defininitions Flashcards
Empirical formula
Formula which shows the simplest whole number ratio of atoms of each element in a compound
Molecular Formula
A formula which shows the actual number of atoms of each element in a molecule
Avogadro’s law
Equal volumes of gases, at the same temperature and pressure, contain the same number of particles
Molar gas volume
The volume of one molecule of one mole of gas under specified conditions of temperature and pressure
Theoretical yield
The maximum possible amount of product from the reactants used
What is coal?
Formed from dead plant material
What is crude oil and gas?
Formed from dead marine organisms
What are hydrocarbons?
Compounds that only contain hydrogen and carbon
Catenate
The ability to form multiple covalent bonds
What is a homologous series?
Compounds which have the same general formula and have similar chemical properties.
What is the functional group?
The part of a structure which determines the characteristic reactions of a compound
What is cracking?
Breaking down molecules into smaller ones
Structural isomers
Molecules which have the same molecular formula but different structural formula
Chain isomers
Similar chemical properties and similar physical properties
What is an electrophile?
An ion or molecule that attacks region of high electron density
Heterolytic fission
Bond breaking in which the shared electrons go to one atom
Homolytic fission
Bond breaking in which one of the shared electrons goes to each atom
Free radical
A particle with unpaired electron
Monohalogenation
When one hydrogen is replaced with a halogen
Primary halogenalkane
Has only one carbon directly attached to the same carbon as the halogen group
Secondary halogenalkane
Has two carbons directly attached to the same carbon as the halogen group
Tertiary halogenalkane
Has three carbons directly attached to the same carbon as the halogen group
Substitution reaction
When one atom of group is replaced with a different atom or group
Nucleophile
An ion or molecule, with a lone pair of electrons, that attacks regions of low electron density
Hydrolysis
The breaking up of molecules by reaction with water
Elimination reaction
A reaction in which a small molecule is removed from a larger molecule
Primary alcohol
Only one carbon directly attached to the same carbon as the hydroxyl group
Secondary alcohol
Has two carbons directly attached to the same carbon as the hydroxyl group
Tertiary alcohol
Has three carbons directly attached to the same carbon as the hydroxyl group
Enthalpy
The amount of energy that a substance contains
Enthalpy change of a reaction
The difference in energy between products and reactants
Endothermic
A reaction in which the enthalpy of the products is greater than the enthalpy of the reactants
Exothermic
A reaction in which the enthalpy of the products is less than the enthalpy of the reactants
Standard enthalpy of combustion
The enthalpy change when one mole of a substance is completely burnt in oxygen under standard conditions
The standard enthalpy of formation
The enthalpy change when one mole of a compound is formed from the elements under standard reaction
What is the conservation of energy?
Energy cannot be created or destroyed, it can only be converted from one form to another
Hess’s Law
The enthalpy change for a reaction is independent of the route taken, provided the initial and final conditions are the same
Average bond enthalpy
Energy required to break one mole of a given bond averaged over many compounds
Standard enthalpy of neutralisation
The enthalpy change when one mole of water is produced in a neutralisation reaction under standard conditions
Standard enthalpy of reaction
Enthalpy change when one mole of a substance is completely reacted under standard conditions
Reversible reaction
One which goes in both the forward and backward directions
Equilibrium
When a reversible reaction in which the amount of each reactant/product remains constant
Dynamic equilibrium
When the rate of forward reaction is equal to the rate of the backward reaction
Homogenous
All reactants and products are in the same state
