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The definition of the activation energy is exactly the same -- the thermodynamic energy barrier that the reactant must pass over to convert to products.
The difference between a thermal and a photochemical reaction is only where the reactants get the energy to get over this barrier. In a thermal reaction, that energy is given by the temperature, and is carried in excited rotational modes, higher kinetic energies and if hot enough, excited vibrational states. In a photochemical reaction, the activation energy is provided by photons, usually in the form of electronic excited states, but could also be vibrational or rotational. The concept of the activation barrier is identical in both cases.
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What is the role of light in photochemical reactions?
it provides energy
What term describes energy that is required to get chemical reactions started?
Activation energy describes the energy that is required to get chemical reactions started.
What is the role of activation energy in inorganic chemistry?
Activation energy is the minimum amount of energy required for a chemical reaction to occur. In inorganic chemistry, activation energy determines the rate at which reactions proceed. Higher activation energy results in slower reactions, while lower activation energy results in faster reactions. By understanding activation energy, chemists can optimize reaction conditions and develop more efficient processes.
Do exothermic reactions require any activation energy?
No activation energy can also be needed by endothermic reactions.
Why do biological reactions have a high activation energy and Why?
Biological reactions often have a high activation energy because they involve complex molecules and reactions that require a significant input of energy to overcome the initial energy barrier. This high activation energy helps regulate the rate of biological reactions and ensures that they proceed only when necessary for the cell or organism.
What is the statement of Stark-Einstein's law of photochemical equivalence?
Stark-Einstein's law of photochemical equivalence states that each photon absorbed or emitted in a photochemical reaction is associated with the activation of one molecule. This law helps to explain the relationship between light energy and the number of molecules undergoing photochemical reactions.
How is thermal energy involed in chemical reactions?
Thermal energy is involved in chemical reactions by providing the necessary activation energy for the reaction to occur. Increasing the temperature increases the kinetic energy of the molecules, making them more likely to collide with enough energy to react. Additionally, some reactions are exothermic, releasing thermal energy as a byproduct.
What is the role of light in photochemical reactions?
it provides energy
What term describes energy that is required to get chemical reactions started?
Activation energy describes the energy that is required to get chemical reactions started.
What is the role of activation energy in inorganic chemistry?
Activation energy is the minimum amount of energy required for a chemical reaction to occur. In inorganic chemistry, activation energy determines the rate at which reactions proceed. Higher activation energy results in slower reactions, while lower activation energy results in faster reactions. By understanding activation energy, chemists can optimize reaction conditions and develop more efficient processes.
Do exothermic reactions require any activation energy?
No activation energy can also be needed by endothermic reactions.
How do catalysts the energy of reactions?
They lower the activation energy required for the reactions to take place
Do reactions require activation energy?
yes
Why do biological reactions have a high activation energy and Why?
Biological reactions often have a high activation energy because they involve complex molecules and reactions that require a significant input of energy to overcome the initial energy barrier. This high activation energy helps regulate the rate of biological reactions and ensures that they proceed only when necessary for the cell or organism.
When is activation energy the same for forward and reverse reactions?
Activation energy is the same for the forward and reverse reactions at equilibrium, where the rates of the forward and reverse reactions are equal. At this point, the activation energy represents the energy barrier that must be overcome in either direction to proceed with the reaction.
How is activation energy relates to the start of chemical reactions?
A chemical reaction begin only if the activation energy has a specific value.
What kind of energy do enzymes reduce?
Enzymes reduce activation energy, which is the energy required to start a chemical reaction. By lowering the activation energy, enzymes make reactions occur more readily and at a faster pace.
