Question

Las temperaturas de fusión y ebullición del agua utilizadas en las escalas de temperatura son valores que es importante indicar el valor que corresponden a una presión de 1atm. ¿Por qué crees que es importante indicar el valor de la presión?

Answer 1

Answer:

Suppose that you have water in a metallic bowl.

Now, you start heating the water until it reaches the boiling point.

At this point the water starts transitioning from liquid phse to gas phase, now, you need to think this as the kinetic energy of the water increases to the point where it is stronger than the pressure and it can "escape" the liquid mass.

Then, if we increase the pressure, the temperature needded to escape (to change of phase) also needs to increase.

A more "thermodinamical" way to explain it, is that we can define a curve P(T) of transitions, and we also can define a curve T(P) (the inverse)

So for different values of Pressure, we should see different values of temperature for the changes of phase.