definitions Flashcards
define enthalpy
a thermodynamic property of a system linked to internal energy.
define a reaction profile
it is a diagram of the enthalpy levels of the reactants and products in a chemical reaction
define a reaction pathway
the route in terms of enthalpy from reactants to products
define the activation energy
Activation energy is the minimum energy required before a reaction can occur.
define the Standard enthalpy of reaction ∆rHº
The enthalpy change when substances react under standard conditions in quantities given by the equation in the reaction.
define the Standard enthalpy of formation ∆fHº
The enthalpy change when 1 mole of a compound is formed from its constituent elements with all reactants and products in standard states under standard conditions.
define the Standard enthalpy of combustion ∆cHº
The enthalpy change when 1 mole of a substance is burned completely in excess oxygen with all reactants and products in their standard states under standard conditions
what is Hess’s law
The enthalpy change of a chemical reaction is independent of the route taken. it only depends on the initial and final states assuming constant pressure.
Define the mean bond enthalpy
It is a measure of the energy required to break one mole of a covalent bond measured in the gaseous state in KJ/mol averaged across many compounds containing the bond
