Class 11 Chemistry Practice Test: Thermodynamics - Enthalpies for Different Types of Reactions — Flashcards

Enthalpies for Different Types of Reactions are:

1.Heat of Formation : It is “The amount of heat evolved (or) absorbed during the formation of one mole of the compound at constant temperature from the constituent elements in the standard state.
Eg : Heat or formation of CO2
C(s) + O2(g) →CO2(g) : ∆H = -393.5KJ
 

2. Enthalpy of fusion : The enthalpy change that accompanies melting of one mole of a solid substance in standard state is called enthalpy of fusion.
H2O(s) →H2O(l) ; ∆H = 6.0KJ /mole 
 

3, Enthalpy of Vapourisation : Amount of heat required to vapourise one mole of a liquid at constant temperature and pressure is called its enthalpy of vapourisation.
 

4. Enthalpy of sublimation : The amount of heat required to convert one mole of a simple substance in the solid state into the gaseouos state without decomposition of the substance.
 

5. Enthalpy of combustion : The heat evolved when one mole of a substance is completely burnt at constant volume in excess of oxygen is called it’s heat of combustion.