Thermodynamics Handout PDF

**THERMODYNAMICS** **Thermodynamics** is the branch of science which deals with all types of energy transformations that accompany physical and chemical processes. **Thermodynamics** is primarily based up on four fundamental generalizations called the Zeroth, First, Second and Third laws pf thermo...

**THERMODYNAMICS** **Thermodynamics** is the branch of science which deals with all types of energy transformations that accompany physical and chemical processes. **Thermodynamics** is primarily based up on four fundamental generalizations called the Zeroth, First, Second and Third laws pf thermodynamics. The laws have been experimentally tested for centuries and have been found inviolable irrespective of whether they are applied to physical, chemical or cellular processes. **BASIC TERMINOLOGY OF THERMODYNAMICS** **SYSTEM** The term system refers to the specified part of the physical world or "universe" chosen for our investigation and separated from the rest of the universe by a real or imaginary boundary. **SURROUNDINGS** The portion of the universe excluded from the system, i.e., the region outside the system, is called surroundings. **UNIVERSE** The system and the surroundings together constitute what is known as the universe. The universe = The system + The surroundings **TYPES OF SYSTEMS: OPEN, CLOSED ANDISOLATED SYSTEMS** A system which can exchange both matter and energy with its surroundings through the boundary is called an **open system.** A system which can exchange energy, but not matter, with the surroundings through the boundary is called a **closed system.** A system which can exchange neither matter nor energy with its surroundings through the boundary is called an **isolated system.** **MACROSCOPIC PROPERTIES -- INTENSIVE & EXTENSIVE PROPERTIES** A thermodynamic property associated with the collective behavior of a large number of particles (atoms, molecules, ions, etc.) is called a macroscopic property. For example, pressure, volume, temperature, density, viscosity, refractive index, surface tension, composition, etc. are some of the macroscopic properties of a system. **INTENSIVE PROPERTIES** Properties which are independent of the quantity or size of matter present in the system are called intensive properties. Temperature, pressure, viscosity, density, surface tension, refractive index, etc. are intensive properties. e.g., A glass - full of water and a tank -- full of water will have the same density. **EXTENSIVE PROPERTIES** Properties which depend upon the quantity or size of the matter present in the system are called extensive properties. e.g., mass, volume, surface area, energy, enthalpy, entropy, free energy, heat capacity. **LAW OF THERMODYNAMICS** Laws of Thermodynamics Thermodynamics laws define the fundamental physical quantities like energy, temperature and entropy that characterize thermodynamic systems at thermal equilibrium. There are four laws of thermodynamics and are given below: \>Zeroth law of thermodynamics: If two thermodynamic systems are in thermal equilibrium with a third system separately are in thermal equilibrium with each other.  **Zeroth Law** (Thermal Equilibrium):\ If two systems are in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. This law is the basis for temperature measurement.  **First Law** (Conservation of Energy):\ Energy cannot be created or destroyed, only transformed from one form to another. This law is often written as: ΔU=Q−W Where: - ΔU is the change in internal energy. - Q is the heat added to the system. - W is the work done by the system.  **Second Law** (Entropy and Spontaneity):\ In any energy transfer or transformation, the total entropy of an isolated system can only increase. Entropy is a measure of disorder or randomness. It implies that natural processes tend to move towards a state of higher disorder (greater entropy). This law also explains why some processes are irreversible and leads to the concept of heat engines and efficiency.  **Third Law** (Absolute Zero):\ As the temperature of a system approaches absolute zero (0 Kelvin), the entropy of a perfect crystal approaches zero. This law indicates the limit of how cold a system can become. **Heat and Work** - **Heat (Q)**: Energy transferred between systems due to a temperature difference. - **Work (W)**: Energy transfer that occurs when a force moves an object over a distance. Thermodynamic processes often involve changes in the state of a system, where heat and work play key roles. **THERMODYNAMIC PROCESS** There are four types of thermodynamic process: **Isothermal Process**: Occurs at constant temperature. **Adiabatic Process**: No heat exchange. **Isobaric Process**: Occurs at constant pressure. **Isochoric Process**: Occurs at constant volume. Practice Test 1. Which of the below is not a type of heat transfer? A. Conduction C. Radiation B. Expansion D. Convection 2. In an isothermal process, there is no change in \_\_\_\_\_\_\_\_\_. A. Pressure. B. Temperature. B. Volume. D. Heat. 3. Which law of thermodynamics states that heat flows from hot to cold objects? A. Zerorth C. Second B. First D. Third #### **A system in thermal equilibrium means:** #### **Which property remains constant in an isobaric process?** #### **In which type of system does energy, but not matter, exchange with the surroundings?** #### **7. Which of the following is an extensive property?** #### **8. Entropy is a measure of:** #### **9. What does the term \"absolute zero\" refer to?** #### **10. In an isochoric process:** #### **11. Which process occurs with no heat exchange?** #### **12. What is heat in thermodynamics?** 1.B 2.B 3.C 4.C 5.A 6.B 7.C 8.C 9.B 10.C 11.B 12.B