In my text book, it is given :
One calorie is defined as the amount of heat required to raise the temperature of water from 14.5 °C to 15.5 °C.
I found out in wikipedia that this is actually the definition of 15 °C calorie.
I want to know that as temperature increases, will the amount of energy for unit increase in temperature decrease? I find 15 °C calorie > 20 °C calorie. Is this relation uniform till 100 °C or is there any anomaly? And does the increased kinetic energy of the molecules of water, at an elevated temperature cause the amount of heat - required for unit rise in temperature, to be greater than the amount of heat required for the same unit rise, but at a lower temperature?
For example, the heat energy required to produce unit rise in temperature of water at 14.5 °C is 4.1855 joules and the amount of heat energy required to produce unit rise in temperature of water at 19.5 °C is 4.182 joules.
So does the increased K.E of water molecules at 19.5 °C cause the required heat energy to be lower than the heat energy required at 14.4 °C?