Calorimeter.pptx practical theory with digram

calorimeter

1. Calorimeter Shiza Arshad

2. Calorimetry Calorimetry is the field of science that deals with the measurement of the state of a body with respect to the thermal aspects in order to examine its physical and chemical changes The changes could be physical such as melting, evaporation or could also be chemical such as burning, acid-base neutralization etc . Calorimetry is applied extensively in the fields of thermochemistry in calculating the enthalpy, stability, heat capacity etc .

3. History In 1761 Black introduced the thought of  heat  of transformation which causes the creation of the primary ice-calorimeters In the year 1780, a French nobleman and chemist Lavoisier performed an experiment in which he used the warmth from the guinea pig’s respiration to melt snow surrounding his apparatus almost like a candle burning, showing that respiratory gas exchange is the combustion

4. What is a Calorimeter? A calorimeter is a device used to measure the heat energy produced or absorbed during a chemical reaction or physical change Composition: It mainly consists of a metallic vessel made of materials which are good conductors of electricity such as copper and aluminium etc There is also a facility for stirring the contents of the vessel. This metallic vessel with a stirrer is kept in an insulating jacket to prevent heat loss to the environment There is just one opening through which a thermometer can be inserted to measure the change in thermal properties inside

5. Working principle The body at higher temperature releases heat while the body at lower temperature absorbs heat The principle of calorimetry indicates the law of conservation energy, i.e. the total heat lost by the hot body is equal to the total heat gained by the cold body Heat Lost = Heat Gained Calorimeters work by isolating the reaction or substance inside a chamber and measuring the temperature change that occurs due to the heat released or absorbed

6. Working principle Say in a calorimeter a fixed amount of sample is burned The vessel is filled with water, and the sample is burned, leading to the heating of the water Heat loss by the sample is equal to the heat gained by the water This is why it is important to insulate the calorimeter from the environment; to improve the accuracy of the experiment This change in heat can be measured through the thermometer Through such a measurement, we can find out both the heat capacity of water and also the energy stored inside a sample

7. Types of Calorimeter Adiabatic Calorimeters Adiabatic calorimeters measure the change in enthalpy of a reaction occurring in solution. During the reaction, the no heat exchange with the surroundings is allowed and the atmospheric pressure remains constant However, The adiabatic calorimeter is actually a wrong term because it’s not fully adiabatic. Some amount of heat is usually lost by the sample to the sample holder. A mathematical correction factor, referred to as the phi-factor, are often wont to adjust the calorimetric result to account for these heat losses

8. Types of Calorimeter Bomb Calorimeters Since the process takes place at constant volume, the reaction vessel must be constructed to withstand the high pressure resulting from the combustion process, which amounts to a confined explosion. The vessel is usually called a “bomb”, and the technique is known as bomb calorimetry . To measure the heat evolved in a combustion reaction, constant volume or bomb calorimetry is ideal. A constant volume calorimeter is also more accurate but it is more difficult to use since it requires a well-built reaction container that is able to withstand large amounts of pressure changes that happen in many chemical reactions

9. A bomb calorimeter structure consists of the following: Steel bomb which contains the reactants Water bath in which the bomb is submerged Thermometer A motorized stirrer Wire for ignition

10. Types of Calorimeter Differential Scanning Calorimeter In this differential scanning calorimeter or DSC, heat flows into a sample which is usually contained within a small aluminium capsule or ‘pan’. This heat flow is measured differentially, i.e., by comparing it to the flow into an empty reference pan

11. Types of Calorimeter Reaction Calorimeter A calorimeter used to start a reaction inside of a sealed, insulated container is known as a reaction calorimeter Heat content is calculated by integrating heat flow versus time after measuring reaction heats. Because industrial processes are designed to operate at consistent temperatures, this property is used in industry to survive the heat

12. Types of Calorimeter Coffee cup calorimeter The cup is partially filled with a known volume of water and a sensitive thermometer is inserted through the lid of the cup so that its bulb is below the water surface. This type of calorimeter is typically used for solution based chemistry with little to no volume change.

13. Uses of Calorimeter Food and Nutrition Caloric Content: Calorimeters, especially bomb calorimeters, measure the energy content in food by burning a sample and measuring the heat produced Metabolic Studies: They help study how different foods affect metabolism by measuring the heat produced during metabolic processes

14. Uses of Calorimeter Diet Design: Calorimeters help nutritionists design balanced diets by accurately measuring the caloric content of various foods Food Labeling: Caloric values obtained from calorimeters are used in labeling food products, providing consumers with important dietary information Nutrient Bioavailability: Calorimetric studies can assess how different cooking methods affect the bioavailability of nutrients in foods

15. Uses of Calorimeter Materials Science Heat Capacity: Calorimeters determine the specific heat capacity of materials, which is crucial for applications like thermal management and material selection in engineering Phase Transitions: Differential Scanning Calorimeters (DSCs) detect phase transitions (e.g., melting, crystallization) in materials, important for quality control in manufacturing

16. Uses of Calorimeter Biochemistry and Medicine Drug Interactions: Calorimeters help in studying the thermodynamics of drug interactions with biomolecules, aiding in drug development Enzyme Activity: They measure heat changes in enzymatic reactions, providing insights into enzyme mechanisms Cell Metabolism: Calorimeters assess metabolic rates of cells, useful in medical research and diagnostics

17. Uses of Calorimeter Industrial Applications Quality Control: In manufacturing, calorimeters ensure the quality and consistency of products by measuring heat changes during production processes Energy Efficiency: They are used to evaluate the energy efficiency of combustion systems, such as engines and boilers

18. Use in Nutrition field A calorimeter is an essential tool in the field of nutrition and dietetics, used to measure the amount of heat released or absorbed by a substance, which is crucial in determining the energy content of food. There are different types of calorimeters used in nutrition, including bomb calorimeters and direct/indirect calorimeters. Here's a detailed explanation of their use

19. Bomb Calorimeter Principle : A bomb calorimeter measures the heat of combustion of a food sample. It provides a direct measure of the energy content by burning the sample in a controlled environment Procedure: Preparation: A food sample is dried and ground to ensure uniformity. Combustion: The sample is placed in a crucible inside the bomb (a strong, sealed container) with a known amount of oxygen. Ignition: The sample is ignited electrically, causing it to combust completely. Heat Measurement: The heat released by the combustion raises the temperature of the surrounding water. The temperature change is measured and used to calculate the energy content of the sample

20. Bomb Calorimeter Application : Nutritional Labeling: Determines the caloric content of foods for nutritional labeling Research: Used in research to study the energy content of different food components, like fats, proteins, and carbohydrates Quality Control: Ensures consistency in the caloric content of food products

21. Direct Calorimeter Principle : Direct calorimetry measures the heat emitted by the human body to calculate energy expenditure. It involves a person staying in a specially designed room where the heat they emit is measured directly. Procedure: Environment Control: The individual stays in a thermally insulated room. Heat Detection: Sensors detect the heat emitted by the person over a specific period. Data Analysis: The heat measurements are used to determine the total energy expenditure of the individual.

22. Direct Calorimeter

23. Direct Calorimeter Application : Metabolic Studies: Provides precise measurements of total energy expenditure Diet Planning: Helps in tailoring diets based on individual energy needs Clinical Research: Used in clinical settings to study metabolism in different health conditions

24. Indirect Calorimeter Principle : Indirect calorimetry estimates energy expenditure by measuring oxygen consumption and carbon dioxide production. This method is based on the principle that the oxidation of nutrients in the body requires oxygen and produces carbon dioxide. Procedure: Respiratory Measurement: The individual breathes into a mouthpiece or mask connected to the calorimeter. Gas Analysis: The calorimeter measures the volumes of oxygen consumed and carbon dioxide produced. Energy Calculation: These measurements are used to calculate the respiratory quotient (RQ) and energy expenditure using specific equations.

25. Indirect Calorimeter

26. Indirect Calorimeter Application : Basal Metabolic Rate (BMR) Measurement: Assesses the energy expenditure at rest Exercise Physiology: Determines energy expenditure during physical activities Nutritional Therapy: Helps in developing personalized nutrition plans for weight management and clinical nutrition

27. Calorimeters play a crucial role in nutrition and dietetics by providing accurate measurements of energy content in foods and energy expenditure in humans Bomb calorimeters are primarily used to determine the caloric content of foods, while direct and indirect calorimeters are used to measure human energy expenditure These tools are vital for nutritional labeling, diet planning, metabolic research, and clinical nutrition, ensuring that dietary recommendations and interventions are based on precise and reliable data