Deck 6 Flashcards
Enthalpy
Enthalpy,H, is the heat content that is stored in a chemical system.
Exothermic
Exothermic refers to a reaction in which the enthalpy of the products is smaller than the enthlapy of the reactants, resulting in heat loss to the surroundings.
Endothermic
Endothermic refers to a reaction in which the enthalpy of the products is greater than the enthalpy of the reactants, resulting in heat being taken in from the surroundings.
An enthalpy profile diagram
An enthalpy profile diagram is a diagram for a reaction to compare the enthalpy of the reactants with the enthalpy of the products.
Activation energy
Activation energy is the minium energy required to start a reaction by the breaking of bonds.
Standard conditions
Standard conditions are a pressure of 100kPa(1 atmosphere), a stated temperature, usually 298K(25*C) and a concentration of 1.0 mol dm^-3(for reactions with aqueous solutions).
Standard state
Standard state is the physical state of a substance under the standard conditions of 100kPa(1 atmosphere ) and 298 K (25*C)
The standard enthalpy change of reaction
The standard enthalpy change of reaction is the enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical equation under standard conditions, all reactants and products being in their standard states.
The standard enthalpy change of combustion
The enthalpy change that takes place when one mole of a substance reacts completely with oxygen under standard conditions, all reactants and products being in their standard states.
The standard enthalpy change of formation
Of a compound is the enthalpy change that takes place when one mole of a compound is formed from its constituent elements in their standard states under standard conditons.
Specific heat capacity
Specific heat capacity,c, is the nergy required to raise the temperature of 1 g of a substance by 1*C.
Bond enthalpy
Bond enthalpy is the enthalpy change that takes place when breaking by homolytic fisiion 1 mol of a given bond in the molecules of a gaseous species.
Average bond enthalpy
Average bond enthalpy is the average enthalpy change that takes place when breaking by homolytic fission 1 mol of a given type of bond in the molecules of a gaseous species.
