What is the Formula for Calculating Entropy Change in a Phase Transition?

[Nicco de Vera]

Homework Statement

Compute the entropy change of 5.00 g of water at 100°C as it changes to steam at 100°C under standard pressure.

Homework Equations

The Attempt at a Solution

5/100+100 is what i did and my teacher says its wrong 'cause its in the formula

 

[Bystander]

wrong 'cause its in the formula

In what formula?

 

[Nicco de Vera]

it is said that the formula was change in S= Change in Q / T

 

[Bystander]

It said absolute temperature; what is the absolute temperature? Further, "Q" is not mass.