Introduction

Melting and freezing behavior are among the characteristic properties that give a pure substance its unique identity. As energy is added, pure solid water (ice) at 0°C changes to liquid water at 0°C.

In this experiment, you will determine the energy (in joules) required to melt one gram of ice. You will then determine the molar heat of fusion for ice (in kJ/mol). Excess ice will be added to warm water, at a known temperature, in a Styrofoam cup. The warm water will be cooled down to a temperature near 0°C by the ice. The energy required to melt the ice is removed from the warm water as it cools.

To calculate the heat that flows from the water, you can use the relationship

$q = {C_p} \cdot m \cdot \Delta t$

where q stands for heat flow, Cp is specific heat, m is mass in grams, and Δt is the change in temperature. For water, Cp is 4.18 J/g°C.

Objectives

In this experiment, you will

• Determine the energy (in Joules) required to melt one gram of ice.
• Determine the molar heat of fusion for ice (in kJ/mol).