how many joules of energy are needed to change 275 g of water from 15 degrees C to steam at 100 degrees C?

Answer 1

q1 = heat needed to raise temperature of liquid water from 15 C to 100 C.
q1 = mass x specific heat H2O x (Tfinal-Tinitial)

q2 = heat need to convert H2O at 100 C to steam at 100 C.
q2 = mass H2O x heat vaporization.