Thermodynamics Flashcards
(18 cards)
What is the enthalpy of formation?
Enthalpy change when one mole of a compound is formed from its constituent elements under standard condition all reactants and products must be in there standard states.
What the enthalpy of combustion?
Enthalpy change when one mole of a substance is completely burnt in oxygen
What is the enthalpy of atomisation?
Enthalpy change which accompanies the formation of one mole of gaseous atoms from the element in its standard state under standard conditions
What are some examples of enthalpy of atomisation?
Mg(s) -> Mg(g)
Atom will go from its original element to a gas
What is the first ionisation energy?
Standard enthalpy change when one mole of gaseous atoms in converted into a mole of gaseous ions with a positive charge
What is the first election affinity?
Standard enthalpy change when a mole of gaseous atoms is converted to a mole a gaseous ions each with a single negative charge
What is an example of first ionisation energy?
Mg(S) -> Mg2+ + e-
What is an example of first electron affinity?
O(g) + e- -> O-
What is the lattice enthalpy of formation?
Standard enthalpy change when one mole of solid ionic compounds is formed from its gaseous ions
What is an example of the enthalpy of lattice dissociation?
Na+(g) + Cl-(g) -> NaCl(s)
What is an example of the enthalpy of lattice dissociation?
The standard enthalpy change when one mole of solid ionic compound dissociated into its gaseous ions
What is the problem of lattice enthalpy of dissociation?
It cannot be measured directly therefore ut gas to be calculated
What is the enthalpy of hydration?
Standard enthalpy change when water molecules surround one mole of gaseous atoms
What is an example of enthalpy of hydration?
Na+(g) + aq -> Na+(aq)
What is the enthalpy of solution?
Standard enthalpy change when one mole of solution dissolves completely in sufficiaent solvent to form a solution in which the molecules and ions are far enough apart not to interact with one another
What is an example of enthalpy of solution?
NaCl(s) + aq -> Na+(aq) + Cl-(aq)
What is the mean bond enthalpy?
Enthalpy change when one mole of gaseous molecules each breaks a covalent bond to form two free radicals averaged out over a range of compounds
What are the steps to lead to the formation of NaCl(s)?
Atomisation of Na Atomisation of Cl Ionisation of Na Election affinity of cl Formation of lattice
