Module 3 Definitions Flashcards
enthalpy change
the heat energy transferred in a reaction at constant pressure
standard enthalpy change of reaction
the enthalpy change when a reaction occurs in the molar quantities show in a chemical equation with all reactants and products in their standard stares, under standard conditions
standard enthalpy change of neutralisation
the enthalpy change when solutions of an acid and an alkali react together to form 1 mole of water, under standard conditions
-negative enthalpy change as mamking H2O
standard enthalpy change of combustion
the enthalpy change when 1 mole of a substance is completely burned in oxygen, under standard conditions
standard enthalpy change of formation
the enthalpy change when 1 mole of a compound is formed from it’s elements in their standard states, under standard conditions
standard states
physical states they are in under standard conditions
standard conditions
100kPa and 298K
activation energy
the minimum amount of energy needed fr a reaction to start
rate
change in the number of reactants or products per unit time
la chatelier’s principle
the position of a dynamic equilibrium shifts to minimise the effect of any change
exothermic reaction
a reaction that releases energy with a negative enthalpy change
endothermic reaction
a reaction that takes in energy with a positive enthalpy change
