posted by Amy~ .
Record the amount of heat needed to change phases for water-ice to steam using graphical analysis.
Is there a one accurate amount of heat needed to change phases, I thought it varied depending the problem...
Would the question be asking for the heat needed in my graph that I got in a lab. This is the hypothesis section.
The question could be related to the lab. Of course, I wasn't there and don't know for sure.
The heat required to change phases is
q = mass x EITHER heat fusion OR heat vaporization.
From that standpoint, yes, it changes with the mass of substance used, in this case it is water, BUT usually it is calculated in J/g or J/mol. The J/g or J/mol number is a constant number and that is what one sees in tables for different substances. I hope this answers your question.