Does water at 0 degree celsius in liquid state when kept in refrigerator at 0 degree celsius temperature changes into ice?Give reason. What is latent heat and specific heat?
The freezing point of pure water is zero degree Celsius. So is water is not freezing at zero degree Celsius, it generally means that it is not pure and either contains some impurity or some dissolved solutes. Though, liquid water can be obtained at zero degree Celsius, the concepts involved are complex which are beyond the scope of discussion at this level. Also, normally the temperature of the freezer in the refrigerator is normally much lower than zero degrees to enable quick freezing of water into ice. The lowest temperature that is can be maintained in the freezer is -18 degree Celsius.
Thus if water at zero degree celsius, in liquid state is kept in freezer in refrigerator, it will freeze as temperature is much lower than zero degrees.
When, in a thermodynamic system, evolution or absorption of heat occurs during a process without any change in temperature of the system, then the heat evolved or absorbed is known as Latent Heat. It can further be categorised as latent heat of fusion, latent heat of vapourisation or latent heat of sublimation.
Specific heat is the amount of heat required to raise the temperature of the one unit mass of the substance by one degree celsius. It is denoted by C
where, Q = Heat supplied
m = mass of the substance
ΔT = change in temperature.
specific heat at constant volume represents the rate of increase of internal energy of the system with temperature. It is represented as Cv.
specific heat at constant pressure represents the rate of increase of enthalpy of the system with temperature. It is represented as Cp.