Definition of terms Flashcards
(17 cards)
enthalpy change
heat change at constant pressure
standard enthalpy change of combustion
the enthalpy change for complete combustion in oxygen of 1 mole of substance under standard conditions
standard enthalpy change of formation
the enthalpy change for 1 mole of substance formed from its constituent element in standard state under standard conditions
standard enthalpy change of neutralization
the enthalpy change when an acid and alkali/base solution react together and neutralize under standard conditions to give 1 mole of water
Hess’s Law
It states that the total enthalpy change of a chemical is independent of the pathway between the initial state and the final state
Average Rate
the rate if reaction in a period of time
Instantaneous Rate
the rate of reaction at any given time
Initial Rate
the instantaneous rate at t=0
Catalyst
it provides alternative reaction pathway with lower activation energy for a reaction to occur
Dynamic Equilibrium
the rate of forward reaction is equal to the rate of backward reaction, no net change is observed
Equilibrium Constant
Kc, which is a constant value for a reaction at equilibrium at a given temperature.
Le Chatelier’s Principle
It states that when a chemical system at equilibrium is disturbed by a change in conditions, the equilibrium position will shift in a direction that tends to counteract / lessen the change
Activation Energy
the minimum energy possessed by the colliding reactant particles in order that a reaction can occur
acid
an hydrogen-containing compound which dissolves in water to give H+ ion as the only positive ion.
basicity of acid
maximum number of ionizable hydrogen atom (H+) present in 1 molecule of an acid
base
a compound which reacts with an acid (H+) to form salt and water only
