What is the relationship between potential energy and stability? | Yahoo Answers
Sep 27, Very generally speaking, stability of a molecule is inversely related to the atoms, and that requires a certain definite amount of potential energy! What is the relation between resonance energy and the stability of a canonical structure?. Jan 30, Interpreting a one-dimensional potential energy diagram allows you to obtain Explain the connection between stability and potential energy. Feb 26, Okay We all know that the most stable state of a system (say an object undergoing SHM)is when it has minimum Potential Energy.
One such family is the hydrocarbons, important in our context because they are the basis of fossil fuels. Note how some of these compounds have double and triple bonds between carbons. This happens when carbon and hydrogen combine under circumstances in which there is not enough hydrogen to satisfy all four bonds of each carbon. For example, if there is plenty of hydrogen to combine with carbon, we get CH4 or C2H6 Ethanewith all single bonds. C2H4 has a double bond between the carbons, and C2H2 has a triple bond.
Compounds with double and triple bonds are called unsaturated, while single bond compounds like C2H6 are said to be saturated. Unsaturated compounds are more reactive than saturated compounds because not all the C atoms are bonded to four other atoms. Hydrocarbons are not the only compounds that can be unsaturated.
Potential Energy Diagrams and Stability - Physics LibreTexts
Carbon monoxide is a good example of an unsaturated compound, "looking" for another oxygen atom to form CO2, a more saturated compound. When carbon in coal or wood, for example burns in an environment with insufficient oxygen, it forms CO which is deadly when breathed in. This is the reason to ensure plenty of access to fresh air when we have a fireplace or running car engine. Note that many representations are two-dimensional, and that in actuality, the electrons forming the bonds are distributed in three dimensions.
In a compound like CH4, the carbon is in the middle of a tetrahedron with the 4 H atoms at the vectors.
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When a formula is written as CH4 just showing the proportion of atoms, it is called an empirical formula. When the bonds are shown as in Figure 15, it is called a structural formula. A single empirical formula may represent different compounds because the structures may be different for the same number of atoms combining. Try drawing propane, butane, and pentane.
Note that there are always four bonds coming from carbon. The linear structures are called aliphatic hydrocarbons. In addition to the linear hydrocarbon molecules, hydrocarbons may also be formed into ring structures. The ring structure possesses the property that enables us to smell these compounds! So they are called aromatic hydrocarbons. The simplest aromatic hydrocarbon is C6H6, benzene. The structure of benzene was long a puzzle in chemistry, with chemists wondering what the structural formula for C6H6 could be.
They knew the empirical formula was C6H6. Note the alternating single and double bonds, a clever way of ensuring four bonds from each carbon shell. The versatility of carbon in forming bonds, ring structures and various configurations is the basis of life on our planet. The chemistry of carbon compounds is therefore called organic chemistry.
More complicated carbons compounds are described in the Ecological System and Materials System. For now, let us look at some additional aromatic and aliphatic compounds, and note some aspects that are relevant to energy storage and release.
Aliphatic hydrocarbons are the basis of fossil fuels. All saturated hydrocarbons react with oxygen at high temperatures to form carbon dioxide and water, and give off energy. This oxidation reaction is the basis of the internal combustion engine. Gasoline normally contains hydrocarbons from C6 to C18, a mixture of over compounds!
8.4: Potential Energy Diagrams and Stability
An example reaction of the combustion of a hydrocarbon is: The combustion reaction of acetylene C2H2 with oxygen gives off such a large amount of energy that it is used as a welder's torch. Ring compounds do not play as large a role in energy production but often occur as byproducts or waste products. These polyaromatic hydrocarbons PAH's pose a serious pollution problem. Ring compounds, based on the benzene ring, are so common in biochemistry that we just draw to represent C6H6.
Adding one more carbon and two hydrogens to the benzene ring gives us C7H8 which is methyl benzene or toluene at right. Ring compounds can get very complicated.
Several organic compounds playing an important role in our physiology are shown in the Ecological System. Chemical Energy Release and Bond Energies The amount of energy released when a bond is formed between atoms is called the bond energy. Bond energies represent a state of potential chemical energy.
We can get energy from a system as it moves from a state of higher potential energy to one of lower potential energy e. Chemical reactions in which the compounds formed after a reaction called products have lower total bond energy than the reactants can release chemical energy.
Such reactions in which energy is given off are called exothermic or more correctly, exoergic reactions. Conversely, reactions that absorb energy are said to be endothermic. Table 8 gives the energies for bonds we will commonly encounter. The potential energy graph for an object in vertical free fall, with various quantities indicated. The line at energy E represents the constant mechanical energy of the object, whereas the kinetic and potential energies, KA and UA, are indicated at a particular height yA.
Since kinetic energy can never be negative, there is a maximum potential energy and a maximum height, which an object with the given total energy cannot exceed: At the maximum height, the kinetic energy and the speed are zero, so if the object were initially traveling upward, its velocity would go through zero there, and ymaxwould be a turning point in the motion.
You can read all this information, and more, from the potential energy diagram we have shown.
Potential Energy and stability | Physics Forums
Consider a mass-spring system on a frictionless, stationary, horizontal surface, so that gravity and the normal contact force do no work and can be ignored Figure 8. You can read off the same type of information from the potential energy diagram in this case, as in the case for the body in vertical free fall, but since the spring potential energy describes a variable force, you can learn more from this graph.
This is true for any positive value of E because the potential energy is unbounded with respect to x. For this reason, as well as the shape of the potential energy curve, U x is called an infinite potential well. However, from the slope of this potential energy curve, you can also deduce information about the force on the glider and its acceleration. We saw earlier that the negative of the slope of the potential energy is the spring force, which in this case is also the net force, and thus is proportional to the acceleration.
This implies that U x has a relative minimum there. If the force on either side of an equilibrium point has a direction opposite from that direction of position change, the equilibrium is termed unstable, and this implies that U x has a relative maximum there.
Strategy First, we need to graph the potential energy as a function of x. The potential energy graph for a one-dimensional, quartic and quadratic potential energy, with various quantities indicated.