Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Thermodynamics: It is the branch of science that deals with the relationship between heat and other forms of energy, particularly in chemical reactions.
System: The specific part of the universe which is under thermodynamic observation or study is called the system.
Surroundings: The rest of the universe, excluding the system, which can interact with it is called the surroundings. Mathematically, .
Boundary: The real or imaginary surface that separates the system from its surroundings is the boundary. It can be rigid, flexible, adiabatic (no heat flow), or diathermic (allows heat flow).
Open System: A system that can exchange both matter and energy with its surroundings. For example, hot coffee in an open beaker where water vapor (matter) and heat (energy) escape.
Closed System: A system that can exchange energy (in the form of heat or work) but not matter with its surroundings. For example, a sealed stainless steel flask containing hot water.
Isolated System: A system that can exchange neither matter nor energy with its surroundings. An ideal thermos flask or the itself are examples of isolated systems.
State of the System: The condition of a system described by measurable macroscopic properties like pressure (), volume (), temperature (), and amount of substance ().
📐Formulae
💡Examples
Problem 1:
Classify the following as open, closed, or isolated systems: (i) Boiling water in a beaker, (ii) A copper wire in a vacuum bulb, (iii) Reactants in a perfectly insulated Dewar flask.
Solution:
(i) Open System, (ii) Closed System, (iii) Isolated System.
Explanation:
Boiling water in an open beaker exchanges both steam (matter) and heat (energy). A copper wire in a sealed bulb can exchange heat through the glass but not matter. A perfectly insulated Dewar flask prevents the exchange of both matter and energy.
Problem 2:
If a system is enclosed in a container with rigid and adiabatic walls, what type of system is it?
Solution:
It is an Isolated System.
Explanation:
Rigid walls prevent work done by volume change (), and adiabatic walls prevent the flow of heat (). Since no matter can enter or leave, and no energy ( or ) is exchanged, it is isolated.