PHYSICAL topic 4 energetics

Question 1

define enthalpy change

Answer 1

heat energy transferred in reaction at constant pressure.

Question 2

define standard enthalpy of formation

Answer 2

enthalpy change when 1 mol of compound is formed from constituent elements in standard states,in standard conditions {100kpa 298k}

Question 3

define standard enthalpy of combustion

Answer 3

enthalpy change when 1 mol of substance completely burnt in oxygen under standard condition {100kpa 298k}