Question

What would be most helpful to find the normal melting point and normal boiling point on a phase diagram?

Answer 1

A ruler?

Explanation:

On a phase diagram, pressure (the `y` axis) is plotted against temperature (the `x` axis). The pressure scale has units of `"atmospheres"` typically, and the temperature scale naturally has units of `"degrees Kelvin"`. Under conditions of low pressure and high temperature, the substance exists as a gas, and at low temperature and high pressure, the substance exists as a solid.

Now the normal melting and the normal boiling points, by definition are the temperatures at which the solid changes to liquid, and the liquid changes to gas at `"ONE ATMOSPHERE"`. So simply draw a horizontal line on the `y` axis, and note the `x` intercepts of the transitions to give these properties.