Measurement Of ∆U And ∆H
Chapter Name : Thermodynamics |
Sub Topic Code : 102_11_06_03_03 |
Topic Name : Measurement Of ∆U And ∆H |
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Sub Topic Name : ∆H Measurements |
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Introduction
• A coffee cup calorimeter is used to measure the heat absorbed by a chemical reaction at constant pressure. • To calculate the heat released the following formula is used : ?H = qp = Cp ?T • The sign ?H of may be positive or negative depending on whether the reaction is endothermic or exothermic.
Pre-Requisites:
• Thermodynamic terms • The state of a system • Enthalpy • Heat capacity
Activity:
Calorimeter.
Real Life Question:
How do we measure the energy associated with any chemical process at constant pressure?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Calorimetry | It is the act of measuring the energy associated with chemical reactions or physical changes. |
| Calorimeter | Calorimeter |
| Heat capacity | The number of heat units needed to raise the temperature of a body by one degree. |
| Coffee cup calorimeter | It is a device used to measure the heat absorbed by a chemical reaction at constant pressure. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Calorimeter | It is an object used for measuring energy change associated with a chemical or physical process. |
Real life uses :
- For measuring specific heat of metal in lab.
Places to visit :
Laboratory.
Practical examples around us
| Examples | Explainations |
|---|---|
| Metals | In labs, usually the specific heat of a metal is measured using coffee cup calorimeter. |
What you learn in Theory:
Measurement of energy associated with a physical or chemical process at constant pressure.
What you learn in Practice:
Applications of Calorimetry at constant pressure (coffee cup calorimeter).