chemistry - chemical energetics Flashcards
(17 cards)
what is the definition of the standard enthalpy change of reaction?
the enthalpy change when molar quantities of reactants react to form products at 1 bar and 298K
what is the definition of standard enthalpy change of formation?
the enthalpy change when 1 mole of a substance is formed from its constituent elements in their standard states at 1 bar and 298K
what is the definition of standard enthalpy change of combustion?
the heat evolved when 1 mole of a substance is completely burnt in excess oxygen at 1 bar and 298K
what is the definition of the standard enthalpy change of neutralisation?
the heat evolved when 1 mole of water is formed in the neutralisation reaction between an acid and a base, at 1 bar and 298K
what does hess’ law of constant heat summation state?
the enthalpy change of a reaction is determined only by the initial and final states and is independent of the reaction pathway taken
what is the definition of bond energy?
the energy required to break 1 mole of a covalent bond in the gaseous state
what is the definition of the standard enthalpy change of atomisation for an element?
the energy required to convert an element into 1 mole of gaseous atoms at 1 bar and 298K
what is the definition of the standard enthalpy change of atomisation for an compound?
the energy required to convert 1 mole of the compound into gaseous atoms at 1 bar and 298K
what is the definition of lattice energy?
the heat evolved when 1 mole of solid ionic compound is formed from its constituent gaseous ions
what is the definition of the first ionisation energy?
the energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of singly charged gaseous cations
what is the definition of electron affinity?
the enthalpy change when 1 mole of electrons is added to 1 mole of gaseous atoms to form 1 mole of singly charged gaseous anions
what is the definition of standard enthalpy change of hydration?
the heat evolved when 1 mole of free gaseous ions is dissolved in an infinite volume of water at 1 bar and 298K
what is the definition of the standard enthalpy change of solution
the enthalpy change when 1 mole of solute is completely dissolved in an infinite volume of solvent at 1 bar and 298K
how do you calculate the standard enthalpy change of solution?
-(lattice energy) + (sum of hydration)
what is the definition of a spontaneous process?
a spontaneous process is one that takes place naturally in the direction states, where the enthalpy change occurs without a need for continuous input of energy from outside the system
what is the definition of entropy?
entropy is a measure of the randomness or disorder in a system, reflected in the number of ways that the energy of a system can be distributed through the motion of its particles
what is the definition of the standard gibbs free energy change of reaction?
the gibbs free energy change needed to convert reactants into products at 1 bar and 298K
