In the figure that shows saturated vapor and liquid condition under varying temperature and specific volume (constant temperature), there are 2 lines, 1 is saturated liquid line, the other is saturated vapor line. so the region in between these 2 lines is called the mixture of saturated liquid and vapor. There is also statement that says the temperature of a substance which below the boiling temperature (saturated vapor) is called a subcooled liquid. So, that means its a pure liquid (without existance of vapor)? "[URL [Broken] My question here is, if it is in the region of mixtures (which mean both liquid and vapor is in equilibrium), and the region of mixtures is below the saturated vapor line (boiling temperature), how could it be subcooled liquid (pure liquid) in the second statement? So, what is it if the substance phase is in the mixture region under certain temperature and pressure and volume? Do you all understand what I mean, me myself already so confused!!!