We can determine why a reaction is slow or fast by looking at the chemical potential of intermediate states.
If the iron Ore is left to itself, it does not mean that it is impossible to get iron metal from it.
We will see later in this chapter that a nonspontaneous process can be made spontaneously by using an external source of energy.
If external energy is supplied, iron can be separated from its Ore.
In Chapter 7 we defined enthalpy as the first candidate in our search for a chemical potential.
It is possible that a chemical system could proceed in the direction of lowest potential energy, just as a mechanical system would.
All exothermic reactions would beenthalpy if this were the case.
It is not the sole criterion for spontaneity.
We can learn more about the driving force behind chemical processes by looking at processes that involve an increase in enthalpy.
The processes listed are endothermic and energetically uphill.
It's very specific if they have anything covered soon.
In the dissolution of a salt into water, the arrangement again changes from an orderly one to a more disorderly one, in which the ions in the salt are randomly dispersed throughout the liquid water.
Increasing strontium becomes more disorderly.
The increase is related to disorder or ran domness.
There is a criterion for spontaneity in chemical systems.
We can think of it as disorder or randomness.
We discuss the significance of the units on his tombstone.
Imagine a system of particles with an ideal gas.
The energy of the system remains constant if the conditions remain constant.
A gas particle has a good deal of energy at any one time.
After a short period of time, the particle may have very little energy because it was hit by other particles.
A snapshot of the system is what a microstate is.
A large number of different microstates can result in a given macrostate.
The snapshot of a given macrostate is generally different from one moment to the next as the energy of the system is constantly redistributing itself among the particles of the system.
We have two systems that are composed of two particles, one blue and one red.
Each system has the same total energy.
System A has one possible microstate because both particles must occupy the same energy level, while System B has two possible microstates because the red and blue particles can occupy different energy levels.
The second microstate is not possible for System A because it only has one energy level.
System B has more microstates that result in the same macrostate.
For a moment, we can better understand the nature of energy.
System B's energy is spread over two levels instead of being confined to one.
The concept of energy dispersal or energy randomization is at the center of entropy.
Randomization of energy and greater dispersal of energy are processes that increase the entropy of the universe.
There are processes that decrease the universe's entropy.
It depends on the state of the discussion of state functions in Section 7.3.
The discussion of work done by an expanding gas is in Section 7.4.
A tube with a stopcock can be used to evacuate a flask containing an ideal gas.
The gas expands when the stopcock is opened.
The total energy of the gas does not change during the expansion.
When the stopcock is opened, several possible final states may result, each with four atoms distributed in a different way.
The possibilities shown in the left margin are state A, state B, and state C.
The atoms are labeled to keep track of the microstates.
Since the atoms are all the same, there is no difference between them.
The exact statistical probability of finding the atoms in state C is six times greater than the proba location of an atom within a flask.
The four atoms are most likely to be found in state C.