posted by Caitlin .
Calculate the heat (in kJ) required to change 40.0g of ice at -30.0 deg C to steam at 150.0 deg C?
Two formulas you need.
Within a phase is
mass x specific heat x (Tfinal-Tinitial)
Use that formula for ice at -30 to ice at zero, for water at zero to water at 100, for steam at 100 to steam at 150.
At the phase change.
mass x heat fusion for melting.
mass x heat vaporization for boiling.
Then add each part to find the total.