A refrigerant is a substance or mixture, usually a fluid, used in a heat pump and refrigeration cycle.In most cycles it undergoes phase transitions from a liquid to a gas and back again.Many working fluids have been used for such purposes. R-401A is a HCFC zeotropic blend of R-22, R-152a, and R-124. 2  It is designed as a replacement for R-12. 3  R-404A is a HFC nearly azeotropic  blend of 52 wt.% R-143a, 44 wt.% R-125, and 4 wt.% R-134a. 4  It is designed as a replacement of R-22 and R-502 CFC.
The temperature of the ice will continue to decrease until it reaches the same temperature as the outside air which is 20 F. Liquid water has more energy than frozen water. When water freezes it gives up some of the water's energy. This energy that is given up is the latent heat of freezing.
To measure the temperature change associated with a reaction, and use it to work out the enthalpy change associated with the reaction, just like in the laboratory, Reasons for doing this would include: The look at how much energy a fuel releases when it is burned, and to compare the energy released when it is burned completely or incompletely in insufficient oxygen. To measure the energy released when foods are consumed and digested, I.e.