How much energy is required to change 25 g of ice at -20 degrees C into water at 20 degrees C?

Answer 1

q1 = energy to move T of ice @ -20 C to zero C.
q1 = mass ice x specific heat ice x (Tfinal-Tinitial) where Tfinal is zero C and Tinitial is -20.
q2 = energy to melt ice @ zero to water @ zero C.
q2 = mass ice x delta H fusion = ?
q3 = energy to move T of water @ zero C to 20 C.
q3 = mass water x specific heat water x (Tfinal-Tinitial) where Tfinal is 20 and Tinitial is zero C.
Total energy Qtotal = q1 + q2 + q3