Steven plots temperature versus time as he heats water while adding energy at a constant rate. Which of the following statements best explains why the heating curve reaches a plateau at 100 degrees Celsius?

W) Energy is required to decrease the entropy [EN-trouh-pee] of the water

X) Energy is required to decrease the enthalpy [EN-thul-pee] of the water

Y) Energy is required to break the hydrogen-oxygen bonds in water

Z) Energy is required to break the hydrogen bonds between water molecules
Z) ENERGY IS REQUIRED TO BREAK THE HYDROGEN BONDS BETWEEN WATER MOLECULES