2.1 Enthalpy Flashcards
exothermic reaction =
-releases energy
-increases in temperature
-negative delta H
endothermic reaction =
-absorbs energy
-decreases in temperature
-positive delta H
The principle of conservation of energy
Energy cannot be created or destroyed, only changed from one form to another
what are standard conditions
-298k (25c)
-1atm pressure
-all substances in standard states
-conc: 1mol/dm^3
what is ⦵
standard conditions
unit for standard enthalpy change
kj/mol
standard enthalpy change of combustion
enthalpy change when
-1mol of a substance undergoes complete combustion
-under standard conditions
how to tell complete combustion has occured
products are just water and carbon dioxide
Standard energy change of neutralisation
enthalpy change when
-1mol of water is formed
-in neutralisation reaction
-under standard conditions
standard enthalpy change of formation
enthalpy change when
-one mole of a compound is formed from its elements
-under standard conditions
-all chemicals in standard states
standard enthalpy change of reaction
-between the number of moles of reactants shown in the equation for the reaction
standard enthalpy change of combustion FORMULA
energy change of water(j) = m(g of water) c at
state hess’s law
total enthalpy change for a reaction is independent of the root taken from the reactants to the products
