enthalpy and entropy Flashcards
(35 cards)
enthalpy change of formation
standard enthalpy change of a compound when
1 mole of the compound is formed from its elements under standard conditions
enthalpy of atomisation
the enthalpy change when 1 mole of gaseous atoms is formed
from the element in its standard state
First Ionisation enthalpy
the enthalpy change
required to remove 1 mole of electrons from 1 mole
of gaseous atoms to form 1 mole of gaseous ions (with a 1+ charge)
First Electron affinity
the enthalpy change that
occurs when 1 mole of gaseous atoms gain 1 mole of
electrons to form 1 mole of gaseous ions with a –1 charge. usually exothermic
Lattice Enthalpy
the standard enthalpy change
when 1 mole of an ionic compound is formed from its gaseous ions
Enthalpy of Hydration
Enthalpy change when one mole of gaseous ions react to form aqueous ions . ALWAYS EXOTHERMIC
Enthalpy of solution
the standard enthalpy
change when one mole of an ionic solid dissolves in
water.
why is the 1st electron affinity exothermic
the ion is more
stable than the atom and there is an attraction
between the nucleus and the electron
why is the 2nd electron affinity endothermic
it takes energy to overcome
the repulsive force between the negative ion and
the electron
Heterogenous equilibrium
Equilibrium species that have different states or phases
Homogenous equilibrium
Equilibrium species that all have the same state or phase
Increase the pressure of the equilibrium mixture at the same temperature.
State, and explain in terms of Kp, how you would expect the equilibrium position to change
Equilibrium position shifts to the right
ratio in kp expression decreases
numerator of kp expression increases to restore kp value
what happens to pressure as equilibrium is reached, when the products have fewr moles
decreases as products have fewer moles
formula vol, molar vol and mol
vol/molar vol = mols
why is 1st IE of magnesium greater than 1st IE of strontium
magneisum has smaller atomic radius
greater nuclear attraction between atoom ajd outer electron
why is second IE of same element greater than the first
2nd electron removed from positively charged ion
greater nuclear attraction between ion and outer electron
why dont br2 and i2 exist as gaseous molecules in standard conditions
energy is needed to break london forces between molecules
Explain in terms of bond breaking and bond forming, why a reaction can be exothermic
More energy is released by forming bonds than energy required when breaking bonds
How hameoglobin transports oxygen around the body, in terms of ligands
Oxygen dativeky bonds with iron
Oxygen is replaced by CO
CO forms stronger bonds than oxygen
Transition element
Element forming one or more ions with partially filled d-subshells
D Block Element
Element with highest energy in d subshell
Which aren’t transition elements
Sc3+ has empty d subshell
Zn2+ has full d
Transition elements are ions with incomplete d subshells
Ligand
Particle with lone pair of electrons that bonds to metals by a coordinate bond
Complex ion
Metal ion with coordinately bonded ligands
