HEAT & CHANGE OF PHASE OF WATER

INPUT   DATA ♥ EXAMPLE Of Input/Output

Title  

Initial temperature   °C  

Final temperature   °C  
Mass of ice/water/steam   g  

     Reset

OUTPUT   VARIABLES   &   GRAPHS

Variables   Values   Units
 ♦  Heating ice   cal   Graphs:
   Bar Chart of Heat Transfer
 ♦  Melting ice   cal  
 ♦  Heating water   cal  
 ♦  Vaporizing to steam   cal  
 ♦  Heating steam   cal  
 ♦♦  Total   cal  
THEORY  &   FORMULAE

Heat Required To Turn Ice To Water

When a material is heated (with no chemical reaction occurring), kinetic energy is added to its molecules usually resulting in a rise in its temperature. The only exception is when the material reaches its melting or boiling points. At those two temperatures, the heat energy goes into changing the state of the material (solid => liquid, liquid => gas). After the state has changed, the temperature will rise again with added heat. The process is reversed during cooling, condensation and freezing.

The amount of heat required per unit mass to raise the temperature by one degree is the specific heat of the material. The amount of heat required to melt a unit mass of the material is called the latent heat of fusion, and to boil it off to gas is called the latent heat of vaporization.

   • Specific heat of water = 1.0 cal/g-°C, ice = 0.50, steam = 0.48
   • Latent heat of melting/freezing = 80 calories
   • Latent heat of boiling/condensation = 540 cal.

The governing equations are:

     ΔH = m·c·ΔT, within each phase
     ΔH = m·L, at phase change

where
     ΔH = heat exchange
     m = mass
     c = specific heat capacity
     L = latent heat
     ΔT = change in temperature

Tips

    ◊ Use link EXAMPLE Of Input/Output  to demo data entry expectations and results; you may edit & use it as starting point

BIBLIOGRAPHY