Discovering Calorimetry: Exploring Heat Measurement

• Mathematics
• Further Education (Key Stage 5)

Discovering Calorimetry: Exploring Heat Measurement

Learning Objective

Understand the principles of calorimetry and its applications.

What do you already know about heat measurement and calorimeters?

The cooling curve of a substance, such as stearic acid, represents the temperature changes that occur as the substance transitions from a higher temperature to a lower temperature.

Introduction to Calorimetry

Calorimetry is a branch of science that deals with the measurement of heat transfer in physical and chemical processes. 

The purpose of calorimetry is to quantify the amount of heat released or absorbed during a reaction or a physical change.

Exothermic and endothermic reactions

Exothermic and endothermic reactions are classifications based on the direction of heat flow during a chemical or physical process.

System , surrounding and boundary  

Exothermic Reactions:

Exothermic reactions release heat energy to the surroundings.

Characteristics:

The system loses energy to the surroundings.

The temperature of the surroundings increases.

The enthalpy change (-ΔH) is negative.

Examples: Combustion reactions, many oxidation reactions, and certain neutralization reactions are often exothermic.

In an exothermic reaction, the products have lower energy than the reactants, and the excess energy is released as heat. An example is the combustion of gasoline in a car engine.

Endothermic Reactions:

Endothermic reactions absorb heat energy from the surroundings..

Characteristics:

The system gains energy from the surroundings.

The temperature of the surroundings decreases.

The enthalpy change (+ ΔH) is positive.

Examples: Dissolution of ammonium chloride in water, photosynthesis, and the reaction between baking soda and vinegar are examples of endothermic reactions.

In an endothermic reaction, the products have higher energy than the reactants, and the additional energy is absorbed from the surroundings. This often leads to a decrease in the temperature of the surroundings.

Types of Calorimeters

There are different types of calorimeters including bomb calorimeters, coffee cup calorimeters, and differential scanning calorimeters.

Principles of Calorimetry

Calorimetry is based on the principle of heat exchange, where the heat released or absorbed in a reaction is measured.

Calorimetry Applications

Calorimetry is used in various fields including chemistry, biology, and environmental science for studying energy changes in reactions.

Calorimetry Experiment

Perform a simple calorimetry experiment to measure the heat of a reaction using a basic calorimeter setup.

Calculating Heat Changes

Learn how to calculate heat changes using calorimetry data and the specific heat capacity of substances.

Real-World Relevance

Understand how calorimetry is used in industries for quality control, food science, and energy research.

Write down 3 things you learned in this lesson.

Have students enter three things they learned in this lesson. With this they can indicate their own learning efficiency of this lesson.

Write down 2 things you want to know more about.

Here, students enter two things they would like to know more about. This not only increases involvement, but also gives them more ownership.

Ask 1 question about something you haven't quite understood yet.

The students indicate here (in question form) with which part of the material they still have difficulty. For the teacher, this not only provides insight into the extent to which the students understand/master the material, but also a good starting point for the next lesson.