how much heat is needed to change 20 g of solid water at 0 c to liquid water at 15 c?

Answer 1

q1 = heat needed to melt solid water at zero to liquid water at zero.
q1 = mass x heat fusion.

q2 = heat needed to raise T from zero C to 15 C.
q2 = mass water x specific heat water x (Tfinal-Tintial)
Total Q = q1 + q2