module 3 section 2 - physical chemistry definitions

Question 1

define enthalpy (2)

Answer 1

• heat content
• in 1 mole of a system

Question 2

define enthalpy change of a reaction (3)

Answer 2

• enthalpy change that accompanies a reaction
• under standard conditions
• when1 mole of a substance reacted

Question 3

define standard enthalpy of combustion (4)

Answer 3

• enthalpy change
• when 1 mole of a substance
• reacts completely w oxygen
• under standard conditions

Question 4

define standard enthalpy change of formation (4)

Answer 4

• enthalpy change
• when 1 mol of a cmpnd
• formed from its constituent elements
• under standard conditions

Question 5

define enthalpy change of neutralisation (4)

Answer 5

• enthalpy change
• 1 mol of water is formed
• when acid neutralised by a base
• under standard conditions

Question 6

define mean bond enthalpy (3)

Answer 6

• mean heat content needed
• for 1 mol of a gaseous bond
• to undergo homolytic fission