Profile
Settings
Refer your friends
Sign out
In the various Chemical processes that require initiation in terms of energy, This energy is called Activation Energy. For Example automobile engines require activation energy. Various combustion and chemical reactions need Activation energy.
Solves samples, questions and formulas related to the activation energy
Q: What is the purpose of activation energy? Why will a reaction occur in the absence of it?
A: A reaction will not occur until reactant atoms or molecules come together. This happens only when the particles are moving, as movement consumes energy. Reactants frequently have to overcome pressures that drive them apart. This necessitates the expenditure of energy as well. More energy is required to begin breaking bonds in reactants.
Endothermic and exothermic reactions activation
Specific chemical processes require a steady supply of energy, known as endothermic reactions. Other chemical processes release energy as they occur, allowing them to continue without additional energy, known as exothermic reactions.
Q: Do exothermic processes need activation energy similar to endothermic processes?
A: All chemical processes, even exothermic ones, require energy to begin. Only once it begins does an exothermic reaction create more energy than the endothermic reaction.
- Identify two values that must be measured to determine the chemical reaction rate and numerous factors that influence the chemical reaction rate.
Answer:
Changing the concentration with the function of time is defined as the reaction rate. Thus, the molarity of either a reactant or a product and the time must be measured.
Temperature, reactant concentration, surface area (only if the solid is included in the given reaction), and the presence or absence of a catalyst are all factors that influence reaction pace.
- Explain why the rates of NO disappearance and N2 production in the reaction 2CO(g) + 2NO(g)→ 2CO2(g) + N2 are not the same (g).
Answer:
Because of the 2:1 stoichiometric ratio of NO to N2, the NO must utilise two moles for every mole of N2 generated. This implies that the rate of NO consumption is twice as quick as the rate of N2 generation.
- What plot of experimental data may be used to calculate a reaction’s activation energy, Ea? What role does Ea play in this reaction?
Answer:
The constant rate of the function for an absolute temperature is the experimental data necessary to calculate activation energy. If you plot ln k versus 1/T, you should get a simple line with a slope equal to –Ea/R, where R is the ideal gas constant in energy units.
- What are the primary conditions for a plausible reaction mechanism? Why do we use ‘possible’ rather than the ‘right’ mechanism?
Answer:
A response mechanism must meet two conditions. First, the total of all stages in the mechanism must equal the observed reaction; that is, the reaction’s stoichiometry should be satiated. Second, the response mechanism must account for the rate law seen experimentally.
As multiple sequences of elementary reactions might satisfy both conditions, reaction mechanisms are deemed ‘plausible’ rather than ‘accurate’.
- Differentiate between an activated complex and an intermediate in a reaction mechanism? (a) What exactly is the rate-determining step?
Answer:
(a) An activated complex is the structure with the greatest energy along the reaction route, which defines the activation energy for the reaction. Any structure identified in the reaction route can be considered an intermediate.
Conclusion:
Finally, methodologies for directly calculating the activation energy of a chemical system at practically any dynamical time scale from simulations at a single temperature have been published. These approaches compute the analytical derivative concerning temperature instantaneously instead of the usual Arrhenius analysis, which calculates the result numerically. They are simply a dynamic application of the fluctuation theory of statistical mechanics.
