enthalpy and entropy

Question 1

enthalpy change of formation

Answer 1

standard enthalpy change of a compound when
1 mole of the compound is formed from its elements under standard conditions

Question 2

enthalpy of atomisation

Answer 2

the enthalpy change when 1 mole of gaseous atoms is formed
from the element in its standard state

Question 3

Enthalpy of sublimation

Answer 3

(same as enthalpy of atomisation)
The enthalpy change for a solid metal turning
to gaseous atoms

Question 4

First Ionisation enthalpy

Answer 4

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)

Question 5

First Electron affinity

Answer 5

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

Question 6

Lattice Enthalpy

Answer 6

the standard enthalpy change
when 1 mole of an ionic crystal lattice is formed from
its constituent ions in gaseous form.

Question 7

Enthalpy of Hydration

Answer 7

Enthalpy change when one mole of gaseous ions
become aqueous ions . ALWAYS EXOTHERMIC

Question 8

Enthalpy of solution

Answer 8

the standard enthalpy
change when one mole of an ionic solid dissolves in
water.

Question 9

why is the 1st electron affinity exothermic

Answer 9

the ion is more
stable than the atom and there is an attraction
between the nucleus and the electron

Question 10

why is the 2nd electron affinity endothermic

Answer 10

it takes energy to overcome
the repulsive force between the negative ion and
the electron