Enthalpy Flashcards
What happens in exothermic
Heat is given out -ive
products have less energy than reactants
the temperature of surroundings increase
what happens in endothermic
Heat is absorbed +ive
products have more energy than reactants
the temperature of surroundings decrease
In an exothermic graph is reactants more than products or less
exothermic graph enthalpy of reactants > products
In an endothermic graph is reactants more than products or less
endothermic graph enthalpy of reactants < products
is exothermic positive or negative
negative
is endothermic positive or negative
positive
What is the definition of enthalpy change
the amount of heat evolved or absorbed in a reaction carried out at constant pressure.
what are the standard conditions
100kpa
298k
per mole
What are the units of enthalpy change
kilojoules per mole (kJ mol -1).
What is activation energy
Activation energy is the minimum collision energy needed for a reaction to occur.
What is the definition of standard enthalpy change of combustion
When one mole of a substance undergoes complete combustion under standard conditions
What is the definition of standard enthalpy change of formation
When one mole of a substance is formed in its standard state from its elements in their standard state
is enthalpy change of combustion exothermic or endothermic
always exothermic
is enthalpy change of formation exothermic or endothermic
usually bot not always exothermic
What is average bond enthalpy
the energy required to break one mole of gaseous bonds to form gaseous atoms
