File Name: 1st and 2nd law of thermodynamics .zip
- The Second Law of Thermodynamics
- Second law of thermodynamics
- SOME HISTORICAL NOTES
- Difference Between First and Second Law of Thermodynamics
The Second Law of Thermodynamics states that the state of entropy of the entire universe, as an isolated system , will always increase over time.
The First Law of the Thermodynamics is related to the conservation of energy, while the Second Law of Thermodynamics argue that some of the thermodynamics processes are impermissible and does not entirely follow the First Law of Thermodynamics. So thermodynamics is the study of energy which exists in various forms like light, heat, electrical and chemical energy. Thermodynamics is very vital part of the physics and its related field like chemistry, material science, environmental science, etc. Therefore laws of thermodynamics deal with the one of the forms of energy which is heat, their behaviour under different circumstances corresponding to the mechanical work. Though we know that there are four laws of thermodynamics, starting from the zeroth law, first law, second law and the third law.
The Second Law of Thermodynamics
There are 4 laws to thermodynamics, and they are some of the most important laws in all of physics. The laws are as follows. Before I go over these laws in more detail, it will be easier if I first introduce Entropy. Entropy is a very important thing in the realm of thermodynamics. Essentially entropy is the measure of disorder and randomness in a system. Here are 2 examples. To get a more detailed picture of entropy we need to look at the concept of Phase Space.
A phase space is just like a graph, but a point on this graph represents the whole state of a system. Imagine I have a box with 4 gas particles inside. Each point in the phase space for this system tells you where all 4 balls are located in the box. In our example we are only interested in the positions of the 4 particles, so each point in phase space must contain an x, y, and z co-ordinate for each particle so our phase space is 3N dimensional, where N is the number of particles in the system.
So in our case, the phase space is 12 dimensional, in order that each point can describe the location of 4 bodies. In all the diagrams I will depict the phase space as 2D to make it easier to convey what it actually represents. For our purposes we will not need to consider the dimensions. If we imagine that each of the particles is a different colour so we can keep track of their positions easier.
If we imagine the case where all of the particles are located in one corner of the container then we have the situation. In terms of the system, there are multiple other combinations of the 4 particles that will be as organised as the above state. Each of these set-ups will correspond to a different position in phase space as they are all different layouts of the system of the 4 particles.
If we add these to the phase space along with the original we get something like. These 5 layouts of the 4 particles, along with the 11 other combinations, make up a set of states that are apart from the colours indistinguishable. So in the phase space we could put a box around the 16 states that defines all the states inside it as being macroscopically indistinguishable. The total phase space of a system will have many regions all of different shapes and sizes and could look like the following.
But how is all this abstract representation linked to entropy. Entropy, given in equations as the symbol , is defined then as. Where is Boltzmann constant and is the volume of the box in phase space. The insertion of the k seemed to have come first from Planck.
Entropy can also be defined as the change when energy is transfered at a constant temperature. Where is the change in entropy, is the energy or heat, and T is the constant temperature. The Zeroth law is so named as it came after the other 3. Laws 1, 2, and 3 had been around for a while before the importance of this law had been fully understood. It turned out that this law was so important and fundamental that it had to go before the other 3, and instead of renaming the already well known 3 laws they called the new one the Zeroth law and stuck it at the front of the list.
The first law of thermodynamics basically states that energy is conserved; it can neither be created nor destroyed, just changed from one for to another,. The energy in a system can be converted to heat or work or other things, but you always have the same total that you started with.
As an analogy, think of energy as indestructible blocks. If you have 30 blocks, then whatever you do to or with the blocks you will always have 30 of them at the end. You cant destroy them, only move them around or divide them up, but there will always be Sometimes you may loose one or more, but they still have to be taken account of because Energy is Conserved. From the second law we can write that the change in the internal energy, , of a system is equal to heat supplied to the system, , minus any work done by the system, ,.
From the definition of entropy above we can replace , and we can also make the replacement giving us. Now if we have a system of particles that are different then we may get chemical reactions occuring, so we need to add one more term to take this into account.
This is possibly the most famous among scientists at least and important laws of all science. It states;. But there is nothing stopping them all randomly moving back to the corner. The third law provides an absolute reference point for measuring entropy, saying that. The value of the entropy is usually 0 at 0K, however there are some cases where there is still a small amount of residual entropy in the system.
For more information click here than others. If you think about it, this makes sense. A wooden spoon takes a lot longer to heat up than a metal one. We say that metal is a good thermal conductor and wood a poor thermal conductor. The formula we use to find how much energy is required to raise 1 kg of a substance by 1K is:.
Laura is cooking her breakfast before work on a Sunday morning please send your sympathy messages that I had to work on a Sunday here. She leaves the fork in the pan whilst she spreads her toast with margarine and grates some cheese. The stove provides J of energy to the fork in the time she leaves it unattented.
It also springs up in chemistry too. Substituting the values given to us in the question you get:. A site to help make science simpler.
Second law of thermodynamics
The second law of thermodynamics establishes the concept of entropy as a physical property of a thermodynamic system. Entropy predicts the direction of spontaneous processes, and determines whether they are irreversible or impossible, despite obeying the requirement of conservation of energy , which is established in the first law of thermodynamics. The second law may be formulated by the observation that the entropy of isolated systems left to spontaneous evolution cannot decrease, as they always arrive at a state of thermodynamic equilibrium , where the entropy is highest. If all processes in the system are reversible , the entropy is constant. An increase in entropy accounts for the irreversibility of natural processes, often referred to in the concept of the arrow of time.
There are 4 laws to thermodynamics, and they are some of the most important laws in all of physics. The laws are as follows. Before I go over these laws in more detail, it will be easier if I first introduce Entropy. Entropy is a very important thing in the realm of thermodynamics. Essentially entropy is the measure of disorder and randomness in a system. Here are 2 examples.
4 First law analysis for a control volume. Detailed 5 The second law of thermodynamics. The first law and coordinate transformations. https://hashimototorii.org∼powers/ame/hashimototorii.org 2W. Kaplan.
SOME HISTORICAL NOTES
Thermodynamics , science of the relationship between heat , work , temperature , and energy. In broad terms, thermodynamics deals with the transfer of energy from one place to another and from one form to another. The key concept is that heat is a form of energy corresponding to a definite amount of mechanical work.
Engineering Thermodynamics pp Cite as. This chapter presents the second law of thermodynamics. This law will conform to your intuition—once you understand its significance and can apply it properly to both closed and open systems.
According to Sommerfeld, the well known Clausius and Kelvin statements of the second law of thermodynamics comprises two parts.
Difference Between First and Second Law of Thermodynamics
Thermodynamics is a branch of physics which deals with the energy and work of a system. It was born in the 19th century as scientists were first discovering how to build and operate steam engines. Thermodynamics deals only with the large scale response of a system which we can observe and measure in experiments. Small scale gas interactions are described by the kinetic theory of gases. The methods complement each other; some principles are more easily understood in terms of thermodynamics and some principles are more easily explained by kinetic theory.
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