Radiation Heat Transfer

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View Factor Orientation (or View factor or shape factor) plays an important role in radiation heat transfer. View factor is defined as, "fraction of radiation leaving surface 'i' and strike 'j' ". Summation Rule (View Factor) If there is are similar surfaces 'i' and 'j' , then: Blackbody Radiation Exchange Radiation Exchange between Opaque, Diffuse, Gray surfaces in an Enclosure 1. Opaque 2. Surfaces 3. Two surface enclosure Radiation Shield It is used to protect surfaces from radiation act like a reflective surface. References: Material from Class Lectures + Book named Fundamentals of Heat and Mass Transfer by Theodore L. Bergman + My knowledge.  Photoshoped pics  are developed.  Some pics and GIF from Google.   Videos from YouTube ( Engineering Sights ).
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Thermochemistry

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Thermochemistry 


Thermochemistry is the branch of thermodynamics which deals with the heat changes accompanying chemical and physical change. 
  • There are two types of energies K.E and P.E in every system and other energies are formed due to their inter-conversion. 
  • The energy appeared in thermochemistry is in the form of heat and work done. 


  • A beaker full of ice cubes melts and in this scenario heat goes into the system from sorrounding.
  • A hot cup of tea cools down and in this scenario heat flows out of the system.

Internal Energy (E) :


Internal energy is defined as:
The total sum of Kinetic and potential energies of a system. 
Internal Energy = K.E + P.E

Enthalpy (H) :

Enthalpy is defined as:
The sum of Kinetic and potential energies of a system at constant pressure. 

 The difference between internal energy and enthalpy is explained in the video given below:

Calorimetry :

Calorimetry is a technique used to measure heat absorbed or released during a chemical reaction. 
There are two types of calorimetry, namely:
  1. Constant Pressure or Water or Coffee-cup Calorimeter. 
  2. Constant Volume or Steel bomb Calorimeter. 

1. Coffee Cup Calorimeter :


  • It is made of Styrofoam cup. 
  • The lit is lose so as to make pressure constant. 
  • The heat lost or gained by the system is given by:
And,
  • It is used to determine the heat transfer in aqueous reaction, dissolution of salt, specific heat of solid, etc. 

The concept of coffee cup calorimeter is clearly explained in the video given below:

2. Steel Bomb Calorimeter :

  • It consist of an isolated tank and the calorimeter is placed in it.
  • It is used to measure heat transfer during combustible reaction. 
  • The formula for steel bomb calorimeter is:

The steel calorimetry is explained in the video given below:

Hess's Law of Constant Heat Summation:


Hess's law states that, 
The total enthalpy change remains constant for a reaction regardless of any path followed. 

 Example :

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