Entropy, Molecule and Chemical reactions

Summary

In a chemical reaction, entropy plays an incredibly big role.

When a system runs out of space to store increasing entropy, it will force itself to change phases. Therefore, in order to have greater capacity to hold the increasing entropy, water turns into vapor at 760 mm at 1 atmosphere of pressure.

Thermodynamic entropy is a measure of disorder. The universe appears to have an increasing amount of entropy, in accordance with the Second Law of Thermodynamics. Entropy often increases when two pure chemicals are combined or when one component is dissolved into another. When we raise the temperature of any substance in a chemical process, molecular mobility increases and entropy does as well. Conversely, if the temperature of a substance is lowered, molecular motion decreases, and entropy should decrease. In nature, the general tendency is toward disorder.

A nice concept in chemical reactions

The potential chemical energy in the bonds keeping the reacting molecules together transforms into lower energy covalent bonds in the product molecules (the quantity of available energy is reduced), while at the same time the product molecules have more kinetic energy and travel faster. The chaos and entropy are increased by this energy that is unavailable.

The application of the second law of thermodynamics is obeyed.

Have you ever questioned if there is any conflict between 1st and 2nd law of thermodynamics in a chemical reaction?

Where is the conflict?

Since chemical reactions are a natural process, they must comply by both of the laws of thermodynamics. The total energy at the beginning of a chemical reaction and the total energy at its end must be equal (first law). The second rule is that there must be more entropy and less useable energy available. How?

Covalent bonds store energy in a variety of ways, some more effectively than others. The new bonds that form when two "high energy" covalent bonds are broken during a chemical process must be at a lower energy level. For instance, when molecules of hydrogen and oxygen unite to form water, the energy stored in their covalent bonds is released.

Where does this energy go?

This energy speeds up the movement of product moles by increasing the kinetic energy. The entropy increases.

Therefore, during chemical reactions, potential chemical energy in the bonds holding the reacting molecules together, become lower energy covalent bonds in the product molecules. The 2nd law of thermodynamics is obeyed.

Molecules and chemical reactions

The covalent bonds connecting atoms together store energy, potential energy. This is frequently known as chemical energy. All molecules move, with the exception of those at absolute zero (the coldest temperature that can exist). Kinetic energy is a type of mobility, and molecules have more kinetic energy when they move more. Solids' molecules just vibrate, not move very much. Liquid molecules travel quicker and further but are sufficiently bonded to one another to keep them contained in the liquid's relatively modest volume. However, in a gas, the molecules spread out and fill the space because they are traveling quickly (over 1,000 miles per hour), randomly, and apart.

There are two possible outcomes when two molecules collide. They will act like little solid spheres and simply bounce off, each travelling in a different direction like the balls on a pool table if they are not bumped too forcefully. The total amount of energy will not change, albeit some kinetic energy may be exchanged.

However, if two molecules collide violently enough, something quite dramatic happens. Some of the kinetic energy is absorbed by the atoms' retaining bonds, which cause them to disintegrate. Atoms separate when there are no forces holding them together, and for the tiniest fraction of a second, they are "free" from one another. This state is extremely unstable situation.

?The "free" atoms start looking for new partners and creating new covalent bonds very instantly. New and distinct molecules are created by the permutations of bonds in new and distinct atom combinations. The newly generated molecules split apart and proceed with kinetic energy to their subsequent encounter. This is the time; a chemical process has occurred.

The responding molecules or reactants of a chemical reaction are the molecules that initially come into contact with one another. The products are the brand-new molecules that result from the rearrangement. Reactants and products are both involved in a normal chemical reaction.

Chemical reactions must abide by both of the laws of thermodynamics since they are natural processes. The total quantity of energy at the start of a chemical process and the entire amount of energy at its conclusion must match (first law). However, according to the second rule, there must be less usable energy available and more entropy. How?

Different covalent bonds store energy in varying amounts, some higher and others lower. If two "high energy" covalent bonds are disrupted during a chemical reaction, the new bonds that form must be at a lower energy level. For instance, the energy held in the covalent bonds of molecules like water is released when molecular hydrogen and oxygen combine to produce water.

For example, when molecular hydrogen and molecular oxygen react together to form water, the energy stored in the covalent bonds of the hydrogen and oxygen molecules is higher than that found in the hydrogen-oxygen bonds of water.?Some of the 'extra' energy that is lost as this happens becomes kinetic energy and the water molecules move faster and further. We say that the liquid becomes 'hot'.

In conclusion, potential chemical energy in the bonds keeping the reacting molecules together transforms into lower energy covalent bonds in the product molecules (the quantity of available energy is reduced), while at the same time the product molecules have more kinetic energy and travel faster. The chaos and entropy are increased by this energy that is unavailable.

The application of the second law of thermodynamics is obeyed.

Chemical reaction and entropy

Systems have a propensity to develop further into a state of increased disorder or randomness in nature. Entropy is a metric for determining how chaotic or random a system is.

The total entropy of the system is also inclined to rise as a result of chemical processes. How can you detect whether a particular process exhibits a rise or fall in entropy? Certain hints are provided by the reactants' and products' molecular states. Entropy at the molecular level is demonstrated by the general scenarios below.

1.The entropy of the liquid state for a given substance is higher than the entropy of the solid-state. Similarly, the entropy of a gas is higher than that of a liquid. Entropy, therefore, rises in reactions that result in gaseous products from solid or liquid reactants. When liquid products are formed from solid reactants, entropy also rises.

2. When a substance is divided into several pieces, entropy rises. Because the solute particles are split apart when a solution is generated, the dissolving process increases entropy.

3. As the temperature rises, entropy increases. The kinetic energy of the substance's particles increases as temperature rises. Compared to particles travelling slowly at a lower temperature, the faster-moving particles exhibit more disorder.

4. processes when the total number of product molecules exceeds the total number of reactant molecules, entropy typically rises. This rule is not applicable when gas is created from nongaseous reactants.

Credit: Google

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Credit: Google