1. Government Engineering College, Bharuch
Chemical Engineering Department
Sem-III
Sub: Process Calculation
Topic: Heat Calculation

2. Prepared By: Er.no.
(1) Singh Sachin ( )
(2) Sujniwala Gyasuddin ( )
(3) Patel Narendra ( )
(4) Raj Pritesh ( )
(5) Gamit Pragnesh ( )
(6) Parmar Ashish ( )
(7) Sharma Akshay ( )

3. Definition of heat: It is the energy in transit between a hot sources and a cold receiver.
Heat is the form of energy which flows from one body to another as a result of a temperature difference.
The driving force that’s produces a transfer of internal energy is termed as temperature and a form of energy which is transferred from a hot body to a cold body as a result of a difference in temperature is termed as heat.

4. SENSIBLE HEAT AND HEAT CAPACITIES
SENSIBLE HEAT AND HEAT CAPACITIES. 1) Sensible heat: The heat that must be transferred to raise or lower the temperature of a substance or mixture of substances. 2) Heat capacity: It is the amount of heat required to increase the temperature of one kg of substance by 1K.It is generally expressed on a unit mass or unit mole basis.

5. 3) Specific heat: It is the ratio of the heat capacity of a particular substance to that of water. * The heat capacity is generally expressed mathematically as : dQ dT
C =

6. Heat of reaction ( Hr) - It is the enthalpy change resulting due to chemical reaction wherein a) The reactants are feed in the stoictiometry amounts and the reaction proceeds to completion. b) The reactants are fed at temperature T and pressure P and the products energy at the same temperature and pressure.

7. * Standard heat of reaction → The enthalpy change associated with a chemical reaction when both reactants and products are in their standard heat,i.e., pure at a temperature of K and a pressure of 0.1Mpa. → It is denoted by the symbol ∆Hr and expressed in KJ/mol. * Heat of formation. → It is the enthalpy change accompanying the formation of one mole of a compound from its element as a given temperature and pressure.

8. Example : 2C(s)+3H2(g)+1/2o2(g)→ C2H5OH(l)………∆=∆Hf
Example : 2C(s)+3H2(g)+1/2o2(g)→ C2H5OH(l)………∆=∆Hf *Standard heat of formation. → It is the heat of reaction when one mole of a compound is formed from its elements in a reaction beginning and ending at and at pressure of 0.1 Mpa. → It is denoted by symbol ∆Hf. A compound is said to be exothermic when its heat of formation is negative and a compound is said to be endothermic when heats of formation is positive.

9. * Heat of Combustion. → It is a heat of reaction of one mole substance with molecular oxygen. The combustion reaction proceeds with a reduction in enthalpy of a system Hence heats of combustion are assigned negative signs. Ex: CH4(g)+202(g)→CO2(g)+H2O(l)……∆H=∆Hc → The standard heat of combustion of a substance is the heat of reaction of the substance with molecular oxygen to yield specified products with both reactants and reactants are in their standard states.

10. Phase change operation
* Phase change operation. → Phase changes such as fusion, vaporization and condensation are accompanied by large changes in enthalpy. When matter undergoes a phase change , the enthalpy change associated with unit amount of matter at constant temperature and pressure is known as the latent heat of phase change. → Vaporization involves a phase change from liquid to vapor. The process of condensation is the inverse of vaporization.

11. Latent heats of phase change are defined as follow
Latent heats of phase change are defined as follow. 1) Latent heat of vaporization: It is the heat required to vaporize a unit amount of liquid at constant temperature and pressure or it is the heat removed to condense a unit amount of vapour into liquid at constant temperature and pressure. The condensation is a reverse of vaporization and hence, latent heat of condensation must be negative of the latent heat of vaporization.

12. 2) Latent heat of fusion : It is the heat required to melt a unit amount of solid to liquid or removed to convert a unit amount of liquid into solid at constant temperature and pressure. 3) Latent heat of sublimation: It is the heat required to vaporize a unit amount of solid at constant temperature and pressure. → Latent heats are generally expressed in KJ/Kg in the SI system. The latent heat of phase change does vary considerably with temperature but hardly varies at all with pressure at the transition point.

13. with temperature but hardly varies at all with pressure at the transition point.

14. THANK YOU.