posted by Tasia .
When a substance changes from one phase to another, which of the following occurs?
the substance loses or gains heat
the average kenetic energy of the substance changes
the temperature of a substance changes
the molecular motion of a substance changes
You know 1 is true because of heat fusion and heat vaporization.
You know 3 is not true since melting or boiling take place AT a particular temperature rather than through a particular range of temperatures.
Look at the other two and see what you think.
It is the last one. I chose the 2nd one and got it wrong.