what factors determine whether a chemical reaction is spontaneous or not?
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There are two factors that determine if a process will be spontaneous or not: Enthalpy- Reactions that give off energy tend to be spontaneous. Entropy- Entropy is a measure of the randomness or disorder in a system. Generally reactions that increase the randomness of the system are spontaneous.
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Most endothermic reactions are non-spontaneous; without a steady supply of energy, the reactions typically come to a stop. ... For endothermic reactions, enthalpy usually goes up. However, a spontaneous endothermic reaction can occur when the changes in enthalpy and entropy yield a negative Gibbs free energy.
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Change in gibbs free energy gives the direction and extent of the reaction. If the free energy of the reactants is greater than that of the products, the entropy of the universe will increase when the reaction takes place as written, and so the reaction will tend to take place spontaneously.
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Chemical processes occur when bonds are broken and reformed. Physical processes occur when intermolecular forces are broken and reformed. A gray area exists between these processes which can be either chemical or physical.
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According to the collision theory, the following criteria must be met in order for a chemical reaction to occur: Molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break. Molecules must collide with the proper orientation.
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However, endothermic reactions do occur spontaneously, or naturally. There must be another driving force besides enthalpy change which helps promote spontaneous chemical reaction.
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For standard electrochemical cells 1: A redox reaction is spontaneous if the standard electrode potential for the redox reaction, Eo(redox reaction), is positive. If Eo(redox reaction) is positive, the reaction will proceed in the forward direction (spontaneous). (see galvanic cells (voltaic cells)).
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Voltage and Spontaneity. A redox reaction will occur spontaneously if its potential has a positive value. We also know from thermodynatmics that a reaction that occurs spontaneously has a negative value for free energy change.
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A spontaneous reaction has a negative delta G and a large K value. A non-spontaneous reaction has a positive delta G and a small K value. When delta G is equal to zero and K is around one, the reaction is at equilibrium. ... This relationship allows us to relate the standard free energy change to the equilibrium constant.
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For endothermic reactions, enthalpy usually goes up. However, a spontaneous endothermic reaction can occur when the changes in enthalpy and entropy yield a negative Gibbs free energy. An endothermic reaction can be spontaneous if entropy increases by more than the change in enthalpy.
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Chemical reactions occur when chemical bonds between atoms are formed or broken. The substances that go into a chemical reaction are called the reactants, and the substances produced at the end of the reaction are known as the products.
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Chemical reactions are also known as chemical changes. There are many different ways to spot a chemical change. Five different signs include odor, temperature change, precipitate formation, production of gas bubbles, and a color change.
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A non-spontaneous reaction has a positive delta G and a small K value. When delta G is equal to zero and K is around one, the reaction is at equilibrium. You have learned the relationship linking these two properties. This relationship allows us to relate the standard free energy change to the equilibrium constant.
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Chemical reactions can be identified via a range of different observables including change in color, energy change (temperature change or light produced), gas production, formation of precipitate and change in properties among others.
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One with a positive ∆G that requires energy input is called an endergonic reaction. Exergonic reactions are said to be spontaneous, because their products have less energy than their reactants. The products of endergonic reactions have a higher energy state than the reactants, and so these are nonspontaneous reactions.
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(1) The concentrations of the products and reactants are equal. (2) The concentrations of the products and reactants are constant. (3) The rate of the forward reaction is less than the rate of the reverse reaction. (4) The rate of the forward reaction is greater than the rate of the reverse reaction.
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Yes, in some cases the physical and the chemical changes can occur together. One such example is the burning of candle. The wax present in the candle changes to liquid state. ... This means that a chemical reaction or change is also taking place.