enthalpy changes

Question 1

define ‘enthalpy’

Answer 1

thermal energy stored in a system

Question 2

what is meant by the enthalpy change of a reaction?

Answer 2

the heat change in a reaction at a constant pressure

Question 3

what are the units for enthalpy change?

Answer 3

kjmol-1

Question 4

what are the standard conditions for enthalpy change?

Answer 4

100kPa
25 degrees

Question 5

define ‘standard enthalpy change of a reaction’

Answer 5

the enthalpy change of a reaction according to molar quantities in the equation under standard conditions

Question 6

define ‘enthalpy change of neutralisation’

Answer 6

enthalpy change when an acid and alkali react to form 1 mole of water under standard conditions

Question 7

define ‘enthalpy change of combustion’

Answer 7

enthalpy change when 1 mole of a substance completely combusts / reacts with oxygen under standard conditions

Question 8

define ‘enthalpy change of formation’

Answer 8

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