Category: Concepts Of Thermodynamics And Properties Of Gases

We have three different relationships among temperature, volume, and pressure of a gas; these are as follows: Boyle’s Law: PV = k at constant temperature. Charle’s Law:  at constant pressure. Gay–Lussac’s Law:  at constant volume. These three gas laws can be combined in one combined gas law. This law can be expressed as Example 1.28: A sample of a gas has a… Continue reading The Combined Gas Law

Pressure of a confined gas increases with increasing temperature. If the temperature of the gas increases enough, the container can explode because of the pressure that builds up inside of it. The relationship between the pressure and temperature of a gas is described by Gay–Lussac’s law. ‘Gay–Lussac’s law states that the pressure of a sample… Continue reading Gay–Lussac’s Law

vJacques Charles carried out experiments on ideal gas and observed a relationship between the absolute temperature and volume of gases at constant pressure. Volume of the gas increases with increase in temperature and decreases with decrease in temperature. The Charle’s law can be stated as: ‘that the volume of a sample of gas is directly… Continue reading Charles’s Law

Robert Boyle, a British chemist gave the first gas law, now known as Boyle’s law. This law describes the relationship between the pressure and volume of a sample of gas confined in a container. Boyle observed that when the pressure on an ideal gas is increased volume decreases. Similarly, when pressure is released the volume… Continue reading Boyle’s Law

There are some relationships among temperature, volume, pressure, and quantity of a gas that could be described mathematically. This chapter deals with Boyle’s law, Charles’s law, Gay–Lussac’s law, and the combined gas law. These laws have one condition in common, i.e., fixed mass. In addition, some other properties of gases such as internal energy, specific… Continue reading GAS LAWS

Third law of thermodynamics is law of entropy. It is a statement about the ability to create an absolute temperature scale, for which absolute zero is the point at which the internal energy of a solid is zero. Third law of thermodynamics states that it is impossible to reduce any system to absolute zero in… Continue reading THIRD LAW OF THERMODYNAMICS

From equation: Example 1.18: A heat engine having an efficiency of 35% is used to run a refrigerator of COP of 4, what is the heat input into the each MJ removed from the cold body by the refrigerator? If this system is used as a heat pump (Figure 1.16), how many MJ of heat would… Continue reading Evaluation of Entropy Change

For a closed system (no mass flow): In terms of rate: For an adiabatic system (when dQ = 0): For an open system steady flow process:

Entropy Defining entropy in an exact word or line is impossible. It can be viewed as a measure of molecular disorder or molecular randomness. As a system becomes more disordered, the positions of the molecules become less predictable and the entropy increases. Thus, the entropy of a substance is lowest in the solid phase and… Continue reading ENTROPY AND ENTROPY GENERATION

The Clausius inequality is given by the equation where δQ represents the heat transfer at a part of the system boundary during a portion of the cycle, and T is the absolute temperature at that part of the boundary. The symbol δ is used to distinguish the differentials of non-properties, such as heat and work, from the differentials of properties, written… Continue reading THE CLAUSIUS INEQUALITY