We are asked to** the enthalpy of fusion, ΔH _{fus}, (in kJ/mol)** given the heating curve.

**Phase changes** occur on the **horizontal parts of the curve** since there are **no temperature changes. **

We go through the following steps to solve this problem:

Step 1. Calculate the heat to vaporize

Step 2. Calculate the molar heat of fusion

Consider the heating curve shown below for 22.86 grams of an unknown substance. You may assume constant pressure conditions. Note: the points are labeled as (amount of heat added, temperature).

Calculate the enthalpy of fusion, ΔH _{fus}, (in kJ/mol). Show all work and circle your final answer. The moles were identified to be 0.496 mol.