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A reaction becomes spontaneous when the Gibbs free energy (G) is negative. The numerical value of this threshold varies depending on the specific reaction.

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5mo ago

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What could make G become negative at a given enthalpy and entropy?

Changing the temperature


What is the type of reaction between an acid and alkaline?

The reaction between an acid and an alkali is a neutralization reaction, where the acid and alkali react to form water and a salt. The pH of the solution will become closer to 7 (neutral) as a result of this reaction.


What happens to a nucleus of an unstable atom?

An unstable nucleus can undergo radioactive decay to become more stable. This can involve emitting radiation in the form of alpha particles, beta particles, or gamma rays. The decay process results in a transformation of the nucleus into a different element or isotope.


Is 2al plus 6hcl - 2alcl3 plus 3h a redox reaction?

Yes, this is a redox reaction because there is a transfer of electrons between the reactants (Al losing electrons to become AlCl3, which is reduced, and H+ ions gaining electrons to become H2 gas, which is oxidized).


Do all chemical reactions need energy to start them off?

Some reactions are called endothermic ("into-energy") meaning that they require excess energy in order to react. This will cause the reaction to feel cold. Other rections are exothermic ("out-energy"), meaning that they give off heat. Reactions only occur when the environment around them contains enough energy (e.g. lighting a fire, cooking) to push them over what's called a reaction threshold. This is their "activation energy". It is different for every reaction. Many reactions that we call spontaneous are actually just reactions that have reached that threshold under normal conditions, which is 1 atmosphere of pressure and 75 degrees Fahrenheit. This is also called Standard Temperature and Pressure, or STP. If you lower the temperature or pressure, these reactions might stop or not occur at all. Other reactions occur at very low temperatures and pressures, and others occur at much higher ones. Every reaction has a temperature-pressure curve which shows under which conditions the reaction will occur. Lastly, there is an effect called catalysis. This uses a material, often a metal, to artifically lower the reaction energy for the components. This happens by bringing the reactants together on the surface of the metal, where they naturally combine. Using catalysis means having to put less energy into a system for the reaction to occur. Catalysts are reusable and do not become part of the products. A good example of catalytics occurs in your own body: enzymes are special strings of proteins which catalyze certain reactions, such as breaking down food or transferring nutrients into and waste out of cells. In some cases, enzymes cause reactions in your body which would otherwise go so slowly that there's no way you could stay alive!

Related Questions

Why is an energy absorbing reaction or an energy releasing reaction more likely to be spontaneous?

To become spontanious,energy should be released.


Is tarnished silver an endothermic reaction?

No, tarnishing of silver is not an endothermic reaction. Tarnishing is a result of a chemical reaction with sulfur compounds in the air, which causes the silver to become dull and discolored. This reaction does not require an input of energy, making it a spontaneous process.


On what conditions does a spontaneous reaction become spontaneous?

For some non-spontaneous reactions, you can change the temperature. For other non-spontaneous reactions, there is nothing you can do to make it spontaneous. Nature favors reactions that increase a system's entropy (disorder) and nature favors reactions that are exothermic (they release enthalpy). Any reaction that does both of these things is spontaneous at all temperatures. Any reaction that does neither of these things is never spontaneous. As far as this question is concerned, the interesting reactions are endothermic reactions that increase entropy and exothermic reactions that decrease entropy. Whether these reactions are spontaneous depends on the temperature. The first variety (endothermic, increase entropy) will be spontaneous at high temperatures; the second (exothermic, decrease entropy) will be spontaneous at low temperatures. To find the temperature at which a reaction becomes spontaneous, one may apply the Gibbs equation: DG = DH - TDS where capital Ds stand for the Greek capital delta.


How can a galvanic cell become electrolytic cell?

A galvanic cell can become an electrolytic cell by applying an external voltage that is of opposite polarity to the cell's spontaneous voltage. This external voltage can overcome the natural tendency of the cell to generate electricity and drive a non-spontaneous chemical reaction in the reverse direction, converting it into an electrolytic cell.


What is the ventilatory threshold?

The ventilatory threshold is the point of exercise where your breathing starts to increase and become labored. It is when you cannot seem to pull in enough air.


What is the name of a reaction that occurs when products become colder?

This reaction is called an exothermic reaction. It releases heat to the surroundings as the products lose energy and become colder.


What are some non- examples of endothermic process?

You are given the following chemical rection N 2 ( g ) O 2 ( g ) → 2 N O ( g ) Provide an explanaition for why this reaction is endothermic (both conceptual, and mathematical); Is this reaction spontaneous at 298 K? If not, at what temperature does it become spontaneous? Data given: Δ H ∘ f = 90.4 kJ/mol for N O and Δ S reaction = 24.7 J/K Let's start with the math to get it out of the way. A reaction is said to be endothermic if its change in enthalpy, Δ H reaction , is positive. We can calculate this change in enthalpy from what the data provides us. Δ H reaction = 2 moles NO ⋅ 90.4 k J m o l − ( 1 mole N 2 ) ⋅ 0 k J m o l − ( 1 mole O 2 ) ⋅ 0 k J m o l Δ H reaction = 2 moles NO ⋅ 90.4 k J m o l = 180.8 k J The trick here was to be aware of the fact that the enthalpy of formation ( Δ H ∘ f ) for elements is zero. Since Δ H reaction > 0 , the reaction is indeed endothermic. Conceptually, this reaction is endothermic despite the fact that a bond (between N and O ) is formed; this happens because the N 2 molecule has its two atoms bonded together by a very strong triple bond, which means that more energy must be put into breaking this bond than is released when the N O molecule is formed. Now, in order for a reaction to be spontaneous, the sign of Δ G the Gibbs free energy - must be negative at the given temperature. We can therefore determine this reaction's spontaneity by using Δ G reaction = Δ H reaction − T ⋅ Δ S reaction Δ G reaction = 180.8 ⋅ 10 3 J − 298 K ⋅ 24.71 ⋅ J K = 173.4 k J The reaction is not spontaneous at this temperature. We can determine at what temperature the reaction starts to be spontaneous by setting Δ G reaction = 0 . 0 = Δ H reaction − T ⋅ Δ S reaction T = Δ H reaction Δ S reaction = 180.8 ⋅ 10 3 J 24.71 J K = 7317 K This reaction becomes spontaneous at 7317 K . As a conclusion, questions about endothermic or exothermic processes revolve around Δ H , Δ S , and Δ G if a reaction's spontaneity is in question.


What is radiation threshold?

Radiation threshold is the minimum level of radiation exposure that can cause detectable effects in an organism. It is the point at which the effects of radiation, such as DNA damage or cellular harm, start to become noticeable. Exceeding the radiation threshold can lead to increased risks of health issues such as cancer and genetic mutations.


What is the definition for radioactivity?

Spontaneous emission of ionizing radiation as a consequence of a nuclear reaction, or directly from the breakdown of an unstable nucleus; The radiation so emitted; including gamma rays, alpha particles, neutrons, electrons, positrons, etc


Is there a way to lower your own threshold for boredom?

We do not understand the question. Do you wish to become bored more easily or less?


What could make G become negative at a given enthalpy and entropy?

Changing the temperature


How can a galvanic cell become an electrolytic?

the redox reaction is reserved