This video lecture from Thermochemistry (F.Sc. Chemistry Book 1) covers the explanation of the reason why enthalpies of some compounds cannot be found from calorimetric method, explanation of the Hess’s law with the examples and illustration of the concept. Find more e-learning material and educational video lectures in Urdu at maktab.pk. These videos are free to use for promotional and commercial purpose by keeping the credits to Maktab.