High-demand questions and answers in Chemical Engineering
Topic – Thermodynamics
1. What is the First Law of Thermodynamics?
Answer: The First Law of Thermodynamics states that energy cannot be created or
destroyed; it can only be converted from one form to another. Mathematically, it is
expressed as ΔU=Q−W where ΔU is the change in internal energy, Q is the heat
added to the system, and W is the work done by the system.
2. What is the difference between a closed and an open system?
Answer: In a closed system, energy can be exchanged with the surroundings, but
matter cannot. In an open system, both energy and matter can be exchanged with the
surroundings.
3. Define Gibbs Free Energy and its significance in chemical reactions.
Answer: Gibbs Free Energy (GGG) is the energy associated with a chemical reaction
that can be used to do work. It is defined as G=H−TS where H is enthalpy, T is
temperature, and S is entropy. A negative ΔG indicates a spontaneous reaction.
4. What is an isothermal process?
Answer: An isothermal process is a thermodynamic process in which the temperature
remains constant. For an ideal gas, the internal energy remains constant during an
isothermal process.
5. Explain the concept of entropy.
Answer: Entropy is a measure of the disorder or randomness of a system. In
thermodynamics, it is a state function that quantifies the degree of uncertainty or the
number of possible microstates available to a system.
6. What is the Second Law of Thermodynamics?
Answer: The Second Law of Thermodynamics states that the entropy of an isolated
system always increases over time. This law implies that natural processes tend to
move towards a state of maximum entropy or disorder.
7. What is the significance of the Carnot cycle?
Answer: The Carnot cycle is an idealized thermodynamic cycle that provides the
maximum possible efficiency for converting heat into work. It is important because it
sets an upper limit on the efficiency that any real heat engine can achieve.
