Define the initial and final states of a well-defined supply of fossil fuels.
We process in sections 6.1 and 6.2.
The amount of energy in the universe is constant no matter what we do, and the internal energy change of a system.
We have treated all forms of energy the same, but the total never changes.
If a part of the universe chosen as the system gains energy is cause of work done on it by external forces or if energy is transferred through heating, then the environment surrounding the system loses an equal amount of energy.
The total energy of a system is constant.
There is something more subtle happening.
Despite being consistent with energy saving, some processes never occur.
A bal that you hold above the floor, bounce a few times, and then stop.
If we choose the system to be Earth, the bal, and the floor, we would say that the internal energy of the system is converted to internal energy after the bal stops bouncing.
The water at the bottom of the waterfall is always warm.
The process at the top of the waterfall does not violate energy conservativism.
This chapter is about that question.
The total energy of a system and environment is constant.
The mechanisms of mechanical work or heating can transfer energy between a system and its environment.
Changes in the forms of energy are1-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-6556 The water at the bottom never cools and flows in the reverse direction.
Let's think about the power of energy.
Imagine a boulder on a cliff.
The particles follow the same path.
We can say that the objects have an organized energy.
The molecule's motion is random rather than organized, and it has the same energy as a falling boulder.
As the bob moves back and forth, the size of the swing will decrease due to air resistance and the bearing at the top of the string.
The air is slightly cooler than it was initially.
The car will gradually slow down.
The ice cube is sitting on the thermal energy from the table and air.
What will cause the ice to melt and leave a pud experiment on the table?
So it turns into ice.
It never happens to be slightly warmer.
In the experiments in which the outcome matches the prediction, the organized energy is converted into less organized energy.
In the experiments in which the outcomes do not match predictions, the unorganized energy would have to be converted into more organized energy.
Such processes don't happen.
Some processes, which are allowed by the first law of thermodynamics, do not occur in nature according to the testing experiments.
In the processes that never happen, energy would have to be converted from disorganized thermal energy into an equal amount of organized energy.
It seems that an isolated system's thermal energy can't be converted into organized energy.
Let's look at other situations to see if this pattern continues.
Use the ideas of "organized" and "random" energy to decide which of the following processes is not reversible.
You can compare the results with your everyday ex car.
The initial and final states of road and tires and the skid marks coming back together should not happen, and definitely below.
We don't see it spontaneously reform into a droplet.
The process is irreversible.
In this chapter, no work was done on the system by the environment.
There is a situation in which we would like to do some work to the system object.
If the cart moves at a speed of 5 m>s before hitting the spring, the energy of the cart would be 125 J.
The spring gains elastic potential energy when some of the energy is transferred to it.
Imagine a second process.
A container with 1 kilogram of water is warmed from room temperature to boiling temperature.
The energy needed to press the spring by the same amount as the moving cart was transferred through heating.
You put the spring in the water.
The hot water doesn't affect the spring at all.
The spring's thermal energy increases as it warms, but its elastic potential energy doesn't change.
The motion of the cart can be used to work on the spring.
The hotter the water, the less elastic the potential energy of the spring is.
Imagine if each system could interact with another system of interest and transfer energy to that other system by doing work on it.
There is 1000 J of chemical potential energy in the 1.
Molecules of gasoline can be created by the chemical potential energy in the gasoline.
The thermal energy in the air particles is 1000 J.
The gasoline burning room increases the thermal energy in its surroundings.
If the barbel is at the same temperature as the air in the room, the Earth and barbel can cause a 888-269-5556 888-269-5556.
The three systems sketched in the air are not useful.
The possible energy conver sion processes are represented in the bar charts.
3 7 1 7 2 is the ranking for the usefulness of the energy.
They are both useful.
The processes for each of the above are described.
We can combine our understanding of irreversible processes, orga nized energy, and the possibility to do work into one rule.
Sadi Carnot was the first person to understand the link between how organized the energy is in a system and how much work it can do.
Carnot wanted to know if a steam engine with a certain amount of fuel could do the maximum amount of work.
He proposed a couple of things.
It is not possible to use the engine's fuel to do work.
The fuel needs to be warm.
The gas expands and pushes the piston in an environment that is cooler than the gas.
The gas does work on the piston if it's considered the system of interest.
If the fuel transfers a certain amount of energy to the gas, only a frac tion of this energy can do the work.
There is a theoretical limit on the work that can be done.
The thermal energy is transferred to the environment.
Real world engines don't reach the theoretical limit when they operate.
Carnot came up with a rule similar to the one we just did, that the energy in a closed system becomes less useful for doing work.
He said that energy in a less useful form can't be converted into the same amount of energy in a more useful form.
You place a room temperature spoon in a cup and transfer the energy from the hot tea to the cool spoon.
The tea and spoon are not at the same temperature.
The air conditioning fails in a building and the energy is transferred through the walls.
Until the inside and outside of the building reach a similar temperature to the outside, the building will remain warm.
Energy is transferred from a high-temperature region to a low-temperature region in both experiments.
The reverse of the processes in which a cool object becomes cooler and a hot object becomes hotter is not observed in the experiments.
The first law of thermodynamics does not allow such processes.
This leads us to another idea about the direction of en ergy conversion in isolated systems.
The boxed statements are in this section.
As the energy of a system becomes less organized, the amount of work it can do on other systems decreases.
Carnot's principle states that it is impossible to build an engine that uses thermal energy to do mechanical work.
In an isolated system, energy transfers from a warmer region to a cooler region.
The second law describes what can and can't happen in an isolated system.
A new physical quantity is needed to make a more quantitative version of the second law.
As the car moves faster and faster, it can gain organized energy from burning gasoline.
A box holding iden tical atoms labeled so we can tell them apart is a very simple thought experiment.
We place a thin divider down a slot in the middle of the box to divide it in half.
There are four atoms in the box.
We insert the divider, count the number of atoms on each side, and then remove it.
We said earlier that each atom is labeled so we can tell them apart.
It is probable that al microstates are equal.
The number of micro states is the most important factor in determining the probability of a macrostate occurring.
There is a statistical approach to irreversible processes.
The equation works when we add the number before the exclamation mark.
The equation can be used for the other macrostates.
The two halves of the box can be arranged in this way.
There is a chance that you will see all atoms on one side of the box.
The situation is different with a larger number of atoms.
The state with 10 on the left and 0 on the right is less likely to occur than the state with 5 on each side.
The state with 100 on the left and zero on the right is more likely to occur than the state with 50 on each side.
If we increase the number of atoms to one mil ion, states with equal numbers of atoms on each side are more probable than states with an equal number on each side.
For one million atoms, there is almost a 1087 times better chance of observing an equal number on each side than there is on the left and right.
The state with the highest probability is the one that is most likely to happen.
The state with the greatest number of microstates has the greatest randomness compared to the state with all particles on the same side.
Suppose the box with the divider contains five atoms.
An isolated system with a lot of particles will evolve to ward states that are more likely to occur.
The state with the highest level of randomness is the one in which the particles are evenly distributed.
A system in the most probable state is said to have reached equilibrium.
There are the same rules in the real world.
The state of a system with particles moving randomly is more probable than the state with particles moving in the same direction.
Try to use something.
The degree of organization of a system's energy is described in a physical quan tity.
We learned that isolated systems evolve into more disorganized states.
We now have a way to quantify this statement.
From a statistical point of view, a gas expanding at constant temperature is a familiar process.
The atoms are grouped together in a small box.
The gas has grown to six times its original value.
The situations are pictured.
The maximum probability state increases dramatically as the box gets bigger.
A J/K is sometimes called an entropy unit.
The maximum probability state has two atoms in it, and you can check the numbers for the other maximum each third of the box.
The box has one atom in it's sixth termined, which is six times bigger than the state's entropy.
We think the atoms are labeled.
The distribution 1, 2, 3 on is reported in the figure on the previous page.
As the number of possible locations for the atoms increases, side 1 and 4, 5, 6 on side 2 are different from side 1 and side 2.
The gas's entropy increases as it expands.
There are four atoms in a small box.
The box is four times larger than the maximum.
The maximum probability macrostate for each situa equation is reported in the figure above.
The last example shows the second law of thermodynamics.
It is a measure of the probability of a macro state.
The high-entropy states are more disorganized.
These high-probability disorganized states are less able to do work on their environment than less probable organized states.
The number of microstates is related to the number of states.
The system can do less work on its environment if the energy is disorganized and there is more random thermal energy.
Our observations of real-world phenomena and the analysis of simple systems are what lead to these ideas.
These simple systems can be calculated with 10 or even 100 particles.
Real systems involve much larger numbers of particles.
It would be difficult to count the number of microstates in a large system.
There is a need for another method to determine the number of particles in a system.
Consider a process in which a Bunsen burner flame is used to heat a gas and it expands at a constant temperature.
When the gas expands, it pushes on the environment.
The internal energy of the system doesn't change since the isothermal process is negative.
Positive heating is used to balance the gas since the environment is doing negative work on the system.
The volume of the gas increases and the gas particles have more Gas, which should increase the system's entropy.
The internal energy does not change.
A limiting case analysis can help us understand this connec tion.
There is a Piston that does ration.
The volume of the gas increases and the pressure decreases as it expands.
This is an isothermal process in which positive energy trans fer through heating is required to balance the negative work done by the envi ronment as the gas expands.
More space is available for the same number of gas particles at the same temperature because of the increasing volume.
The temperature of the system can change when energy is transferred between environments.
The tempera ture of the system won't change much since this is a small amount of energy.
The average temperature of the process can be used to find the change in entropy.
The summary is here.
You use Eq.
Consider a very simple example.
A water bottle is left outside on a sunny day.
The change in the water in the bottle is estimated.
The process in which objects at different tempera tures reach thermal equilibrium can be applied to this definition.
The magnitude of the system's change was greater than the environment's.
The change of the system and environment's entropy is positive.
When objects of different temperature came in contact, this process occurred.
This leads to another version of the second law.
We are now using Eq.
The figure below shows the process.
The water is warm.
The temperature of the water is -40,800 J.
Intermediate temperature water is formed by equal amounts of warm and cool water.
The warm water transfers from the warm system to the cool system through heating.
The combined system can occur spontaneously if it is isolated from this process.
If you start with the water at 50 C and use the average temperature of each system as they un- waited for half the water to cool to 30 C, you will have a good idea of what to expect.
The reverse of the above process is that there are half warmed to 70 C.
The system's entropy would go down.
A puddle of liquid water at 0 C has a negative heating of 3.35 J>kg.
Living beings grow from less complex forms to more complex forms.
The second law of thermody namics does not apply to the growth of an organisms.
The second law only applies to an isolated system and a growing organisms is not an isolated system.
It interacts with the environment.
The analysis is different if we consider the environment as part of the system.
The flower leads to the formation of some acids in the system.
The formation of these complex useful compounds seems like a violation of the second law of thermodynamics.
Two or more atoms combine to form a more complex molecule in a complex set of reactions.
When these reactions occur, the energy is released into the environment.
The corre sponding decrease is two times greater than the environment's increase due to the formation of the larger molecule.
A net increase in the Earth system is produced by photosynthesis.
A person grows and develops into a complex, highly ordered adult by consuming and converting complex molecules with low en tropy into simpler ones.
A human transfers roughly two billion joules of energy to the environment during a year of consumption, a form of energy that has little ability to do work.
The human may become more complex and orga nized, but the environment will still increase more than enough to compensate.
The increase of the environment in industrialized countries that burn low-entropy fuels such as petroleum and coal to meet their energy needs is 100 times greater than in nonindustrialized countries.
When we convert the organized energy of petroleum to less organized forms of internal energy, the potential of using that energy for useful purposes is lost.
The internal energy of a system is a state function, but work and heating are not.
An isolated system's energy can be converted into less useful forms over time.
The system might have two "reservoirs" at different temperatures.
A pond of cool water, a flame that converts water into steam, or the burning fuel in a car engine are just some of the things that could be a reservoir.
The components of a thermodynamic engine can be harnessed.
It's surprising that we can create a device that makes a cool object.
The first thing we will look at is how a thermodynamic engine works.
We will look at how a fridge works.
There is an electric generator.
The sequence is repeated.
Coal, natural gas, or nuclear fuel can be used in a power plant, or gasoline in a car engine.
A gas that expands can be used to do work.
In the second step, the working substance expands and becomes hot enough to turn the turbine of a generator.
The turbine generator is now cooler.
The work on the environment is aided by a compressor.
Positive net work done by the working substance on the 1.
The net internal energy change of the substance is zero.
The second and third terms are not positive.
The quantities in the equation have positive values.
Figure 13.6c shows a schematic model of the engine in an electric power plant.
A spark plug ignites gasoline in a car engine, causing an explosion in the cylinder.
700 J of energy is transferred from the burning fuel to the gas in the cylinder.
The gas does a net 200 J of work on the environment during the expansion and contraction of the gas.
The cooling system of the car is made of gas and air.
The cooling system is cold.
The energy is transferred from H to Sub.
The substance does positive work on the cooling system of the car and the efficiency of the engine, so we need to find the energy transferred through heating.
The substance gets 70% of its energy from the hot reservoir.
When you stand near a parked car when the en gine is running, the result agrees with what you know.
We model the car's engine as a into the atmosphere, carrying away energy that has served the engine, and represent the process with a bar chart in the figure at right.
The hood of the car is 746 J>s warm, releasing even more energy to the environment.
The car in this example has the same effi- and ciency as the engine in another car.
The 29% efficiency of the automobile engine in the last example is a little de standard gasoline engines.
H to Sub is the amount of energy transferred to the engine.
Scientists and engineers wondered if they could improve the efficiency of the engines when they were being developed to pump water out of mines.
All temperatures are in units of kelvin.
Reducing internal friction between the engine parts may improve efficiency, but never above the value given by Eq.
The maximum efficiency is determined by the temperatures of the hot and cold reservoirs.
The temperature of the exploding fuel in the cylinders of cars is 200 C, while the temperature of the exhaust system of the car is 60 C.
Gas mileage in cars can vary a lot.
The number is for a relatively low-efficiency car.
There are ways to increase the maximum efficiency of an engine.
The hot reservoir should be increased in temperature.
A pebble bed nuclear power plant reactor can operate up to 1600 C with efficiency up to 50%, which is supposedly more safe than traditional nuclear reactor.
The shape of the fuel elements is what inspired the name pebble bed.
Diesel fuel burns at a higher temperature than gasoline, which makes diesel car engines more efficient.
The temperature of the cold storage should be reduced.
It requires a more advanced cooling system.
In a car engine, a device known as an intercooler is used to cool compressed air before it enters the cylinder.
The working substance is less hot than the working substance.
Reversing the operation of an engine.
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