Apologia Chemistry Module 13

Enthalpy (H)
Click the card to flip 👆
1 / 29
Terms in this set (29)
Hess's LawEnthalpy is a state function and is therefore independent of path (the amount of energy in a substance is independent of how it is made)Enthalpy of Formation (∆H(f))The ∆H of a formation reactionStandard conditions25°C and 1.00 atmStandard enthalpy of formation (∆H(f)°)∆H(f) measured at 25°C and 1.00 atm∆H°∑∆H(f)°(products) - ∑∆H(f)°(reactants)The ∆H(f)° of an element in its elemental form is _______0Activation energyThe energy necessary to start a chemical reactionEntropy (S)A measure of the disorder that exists in any system Joules/mole*K OR kcals/mole*K OR kJ/mole*KSecond Law of ThermodynamicsThe entropy of the universe must always either in crease or remain the same. It can never decrease.The _______ state has the least amount of entropy associated with it.solidThe entropy of a system _______ with increasing temperature.increasesThe entropy of a system ______ as the matter it contains increases.increases∆S° =∑∆S°(products) - ∑∆S°(reactants)Gibbs Free Energy (∆G)∆H - T∆S where T = temperature of surroundings (in Kelvin)When ∆G < 0, the reactionis spontaneousWhen ∆G > 0, the reactioncannot proceedAn exothermic reaction that increases energy ...is always spontaneousAn endothermic reaction that decreases entropy ...will never occurThe ∆G°(f) of any element in its elemental form is _______0