Consider the following two reactions:
5 Fe2+(aq)+MnO41-(aq)+8 H1+(aq)-->5Fe3(aq)+Mn2+(aq)+4 H2O(l)
2 MnO41-(aq)+5 C2O42-(aq)+16 H1+(aq)-> 2 Mn2+(aq)+CO2 g)+8 H2O(l)
Both of these reactions result in the purple permanganate (MnO41-(aq)) ion reacting to form the colourless manganese (II) ion. The difference is that the first reaction happens in a few seconds, while the second occurs over several minutes. Explain why this so, based on what you know of chemical reactions and what you can see in these two reaction equations.
Based on the given reactions, we can observe that both reactions involve the conversion of the purple permanganate (MnO41-(aq)) ion to the colorless manganese (II) ion (Mn2+). However, the first reaction occurs rapidly, while the second reaction takes several minutes.
To understand this difference in reaction rates, we need to consider a few factors that influence the rate of a chemical reaction.
1. Concentration: The first reaction involves 5 Fe2+ ions (aq), MnO41- ion, and 8 H+ ions in the reactant side, while in the second reaction, there are only 2 MnO41- ions, 5 C2O42- ions, and 16 H+ ions. The higher concentration of reactants in the first reaction promotes more collisions and faster reaction rate compared to the second reaction, which has lower concentrations of reactants.
2. Catalysts: It is not explicitly mentioned in the given reactions, but the presence of a catalyst can significantly impact reaction rates. Catalysts lower the activation energy required for a reaction to occur, allowing it to happen more easily and quickly. If the first reaction is catalyzed, it would explain its faster rate compared to the second reaction, which might lack a suitable catalyst.
3. Nature of reactants: Each reactant has its own unique chemical properties that can affect the reaction rate. In the first reaction, the presence of Fe2+ ions can facilitate the transfer of electrons during the reaction, making it faster. On the other hand, in the second reaction, the involvement of C2O42- ions might introduce more complex steps or intermediate species, leading to a slower reaction rate.
Additionally, there could be other factors at play that are not apparent from the given information, such as temperature, pH, and possible side reactions. These factors can also influence the rate of a chemical reaction.
In summary, the difference in reaction rates between the two reactions can be attributed to factors like concentration, catalysts, and the nature of reactants.