Chem definitions Flashcards
What is a alkane
Saturated hydrocarbon with the general formula CnH2n+2
Define free radical
Uncharged species with an unpaired electron that is used to form a covalent bond
Substitution reaction
Reaction in which one atom or group is replaced by another atom or group. Always two reactants and two products
What is a pi bond
Two p-orbitals overlapping above and below the internuclear axis
What is a biofuel
A biofuel is made from renewable organic materials, such as sugar, grain, or vegetable oils
Define the term electronegativity
Electronegativity of an element is the ability which it attracts a pair of electrons in a covalent bond towards itself
Standard enthalpy of formation
The enthalpy change when mol if a substance is formed from it’s elements in their standard states at 1 atm less here and at a stated temperature, usually 298K
Standard enthalpy of reaction
The enthalpy change when the number of moles of the substances in the equation as written react under standard conditions of 1 atm pressure and a stated, usually 298K
Standard enthalpy of formation
The enthalpy change when 1 mol of a substance is formed from it’s elements in their standard states at 1 atm pressure and at a stated temperature, usually 298K
Standard enthalpy of combustion
The enthalpy change when 1 mol of the substance is burnt in excess oxygen and under standard conditions of 1 atm pressure and a stated temperature (25*C)
Specific heat capacity
Heat requires to increase the temperature of 1g of the substance by 1*C
Ectothermic reaction
Chemical energy is converted into heat energy and the temperature rises
Endothermic reaction
Heat energy is converted into chemical energy and the temperature system falls
Enthalpy
The chemical energy in the system at constant pressure that can rn converted into heat
Define the term enthalpy change of reaction
Enthalpy change when the number of moles of reactants, react as specified in the balanced equation
Addition reaction
Two reactants form a single product
Substitution reaction
One atom or group of atoms replaces another atom or group of atoms in a molecule
Elimination reaction
Two atoms are removed from adjacent carbon atoms in a molecule of an organic substance
Polymerisation
Thousands of monomer molecules join together to form a long polymeric chain
Oxidation
Addition of oxygen or removal of hydrogen
Hydrolysis
Water splits an organic molecule into two parts
Nucleophile
A species with a lone pair of electrons that it uses to form a covalent bond
Electrophile
Attacks places of high electron density and forms a covalent with a pair of electrons from the electron rich site
Molecular formula
Shows the number of atoms of each element in one molecule of the substance
