True or False:
1. A rate law can be written from the molecularity of the slowest elementary step.
2.The final rate law can include intermediates.
3.The rate of a reaction is dependent of the fastest step in the mechanism.
4.A mechanism can never be proven to be the correct pathway (or only correct pathway) for a reaction.
Answers:
1. True because the overall reaction is limited by, and equal to, the rate of the slowest step in the mechanism.
2. False because they are use as helpfull substances to help achieve the overall reaction.
3. False because is dependent on the slow step of the overall mechanism.
4. True because since mechanism are done at the nanoscale, the only plausible evidence we can see is when done in a experiment. Basically is a theoretical mechanisms.
you are correct
To answer these questions, we need to understand the concepts of rate laws, intermediates, and reaction mechanisms.
1. A rate law can be written from the molecularity of the slowest elementary step.
True. The rate law describes the relationship between the concentrations of reactants and the rate of a chemical reaction. In a reaction mechanism, which is a series of elementary steps that describes the pathway of a reaction, the overall rate is determined by the slowest step. This step is called the rate-determining step, and its molecularity (number of reactant molecules involved in the step) can be used to write the rate law for the entire reaction.
2. The final rate law can include intermediates.
False. Intermediates are temporary species that are formed and consumed during a reaction. They do not appear in the overall balanced chemical equation, and they can only be detected or measured indirectly. The rate law is based on the concentrations of the reactants and products involved in the overall reaction, not on intermediates.
3. The rate of a reaction is dependent on the fastest step in the mechanism.
False. The rate of a reaction is determined by the slowest step in the mechanism, not the fastest. This slowest step is the rate-determining step and limits the overall rate of the reaction. The faster steps may occur before or after the rate-determining step and have no impact on the overall rate.
4. A mechanism can never be proven to be the correct pathway (or only correct pathway) for a reaction.
True. Mechanisms are proposed based on experimental evidence, theoretical models, and chemical intuition. However, since chemical reactions occur at the nanoscale, it is challenging to directly observe and verify the individual steps of a mechanism. Therefore, while a proposed mechanism can be supported by evidence and provide a plausible explanation, it can never be definitively proven as the only correct pathway for a reaction.