Enthalpy – Student Design

In this experiment, students will have the opportunity to develop their practical and analytical skills, which are essential for the IA internal assessment or practical exams. By investigating the enthalpy change that occurs when solid ammonium chloride dissolves in water, students will learn how to conduct a scientific experiment using calorimetry techniques. This experiment will also allow students to calculate the enthalpy change and analyze their results, which will help them to understand the importance of accuracy and precision in scientific measurements. By engaging in this experiment, students will gain valuable experience in carrying out practical chemistry experiments and will be better equipped to succeed in their internal assessments or practical exams.

Aim

The aim of this experiment is to determine the enthalpy change for the process:

NH₄Cl_(s) + H₂O_(l) → NH₄Cl_(aq)

Introduction

The enthalpy change of a reaction is a measure of the energy transferred in the form of heat during a chemical reaction. In this experiment, we will measure the enthalpy change when solid ammonium chloride (NH4Cl) dissolves in water (H2O) to form an aqueous solution of ammonium chloride.

The purpose of this planning experiment is to determine the quantities, volumes, and types of equipment required to measure the enthalpy change accurately and precisely. By using reliable experimental techniques, we can obtain precise and accurate data, which will allow us to calculate the enthalpy change of the reaction with greater confidence.

The process we will be investigating is very similar to the Enthalpy – Displacement experiment. However, the maximum temperature change occurs very rapidly, so we do not need to plot a temperature/time graph.

Requirements

Make a list of requirements including the masses and amounts needed; show the list to your teacher or technician.

Procedure

You will need to work out the procedure yourselves, keeping an accurate record of our steps to ensure precise and accurate data.

Results

1. Tabulate your results in an appropriate form.
2. Calculate the enthalpy change of solution for the thermochemical equation in the aim.

Question

After calculating the enthalpy change, we will compare our result with the accepted value of +16.4 kJ mol-1. We will then suggest reasons for any difference between our result and the accepted value, taking into consideration any sources of error that may have affected our measurements.