enthalpy definitions

Question 1

Enthalpy change of reaction is the

Answer 1

enthalpy
change when the number of moles of reactants as specified in the
balanced equation react together

Question 2

The standard enthalpy change of formation of a compound is the

Answer 2

enthalpy change when 1 mole of the compound is formed from
its elements under standard conditions (298K and 100kpa), all
reactants and products being in their standard states

Question 3

The standard enthalpy of combustion of a substance is defined as

Answer 3

the enthalpy change that occurs when one mole of a substance is
combusted completely in oxygen under standard conditions.
(298K and 100kPa), all reactants and products being in their
standard states

Question 4

The standard enthalpy change of neutralisation is the

Answer 4

enthalpy change when solutions of an acid and an alkali react together under standard conditions to produce 1 mole of water.

Question 5

Enthalpy of atomisation

Answer 5

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

Question 6

Enthalpy of sublimation will be the same as

Answer 6

the enthalpy of atomisation

Question 7

First Ionisation enthalpy

Answer 7

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 8

Second Ionisation enthalpy

Answer 8

enthalpy change to remove 1 mole of electrons from one mole
of gaseous 1+ ions to produces one mole of gaseous 2+ ions.

Question 9

First Ionisation enthalpy example

Answer 9

Mg (g) -> Mg+(g) + e-

Question 10

Second Ionisation enthalpy example

Answer 10

Mg+(g) -> Mg 2+ (g) + e-

Question 11

First Electron affinity

Answer 11

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

Question 12

First Electron affinity example

Answer 12

O (g) + e- -> O- (g)

Question 13

second electron affinity

Answer 13

enthalpy change when one mole of gaseous 1- ions gains one
electron per ion to produce gaseous 2- ions

Question 14

second electron affinity example

Answer 14

O –(g) + e- -> O2- (g)

Question 15

The Lattice Enthalpy is the

Answer 15

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

Question 16

Enthalpy of Hydration

Answer 16

Enthalpy change when one mole of gaseous ions become 1 mole of aqueous ions

Question 17

enthalpy change of solution

Answer 17

enthalpy change when 1 mole of solute dissolves completely in a solvent, water