posted by Julia .
How many kilojoules of heat energy are needed to change 49.6 g of ice at 15 degrees celsius to water at 58 degrees celsius?
I am having trouble figuring out how to solve this.
I can't help because I'm confused by the problem. How can you have ice at 15 C? You can't. You must have made a typo; I suspect it is -15 C.
Here is the general procedure.
For change of state (change of phase), heat needed is
q = mass x heat fusion (if melting/freezing) or heat of vaporization (if vaporizing/condensing) and if moving within a phase (the same state)
q = mass x specific heat x (Tfinal-Tinitial).
Then total Q = sum of individual qs.