It is common knowledge that the majority of chemical and physical changes are accompanied by energy changes. These energy transformations can manifest as heat, light, work, electrical energy, etc. Various energy sources can be converted into one another. Thermodynamics is the discipline of science concerned with analysing various energy types and their quantitative relationships.
The importance of thermodynamics lies in the following facts :
1. It enables us to foretell whether a specific chemical reaction will take place under a specific set of conditions.
2. It aids in estimating the reaction extent before equilibrium is reached.
3. It aids in determining whether a reaction is feasible or not.
4. It solely addresses a system’s initial and final states.
5. It deals with the characteristics of the substance as a whole, such as a temperature, pressure, etc.
Below is a brief explanation of some fundamental thermodynamic terms and concepts:
1. Surroundings and System: The part of the universe that has been chosen for thermodynamic consideration is called a system. The remaining part of the universe, excluding the system, is called the surroundings.
2. Types of Systems (Open, closed and Isolated systems)
a) Open System: If a system can exchange both matter and energy with its surroundings, it is considered to be an open system.
b) Closed System: A system is said to be closed if it cannot exchange matter with its surroundings but can exchange energy.
c) Isolated System: An isolated system is one that is incapable of exchanging either energy or matter with its surroundings.
3. State of a system and State variables: The state of a system means the condition of the system, which is described in terms of certain observable properties such as temperature, pressure, and volume of the system. If any of these properties of the system change, the system is said to be in a different state. That is why these properties of a system are called state variables.
The above-discussed concepts and terms are frequently utilised when discussing the thermodynamics questions.
Chemistry is characterised as the discipline of science that examines the composition, structure, and characteristics of matter, as well as the changes that the substance experiences under various conditions and the laws that control these changes.
Chemistry plays an important role in our life in the following ways:
1. It has made available chemical fertilisers like urea, calcium superphosphate, sodium nitrate, ammonium sulphate, and others that have increased the number of fields of crops and fruits.
2. Food products like jam, butter, squashes, etc., have been preserved for extended periods of time thanks to the application of preservatives.
3. It has provided techniques for detecting adulterants, and ensuring the supply of pure food products.
4. Chemistry has helped to improve hygienic conditions and health.
5. It has given the human race a lot of life-saving medicines.
In everyday life, we come across a number of measurements e.g.; we buy vegetables in kilograms, milk in litres, cloth in metres etc. However, during scientific studies, in addition to the measurements of mass, volume and length, we come across the measurement of a number of other quantities such as temperature, pressure, concentration, force etc. All such quantities which we come across during our scientific studies are called physical quantities.
Evidently, the measurement of any physical quantity consists of two parts : (i) the number and (ii) the unit.
To derive the units of any physical quantity and to check the accuracy of any scientific equation in chemistry questions is done by seeing that the dimensions of both sides of the equation are the same, i.e. concept of dimensional analysis.