Which of the following is the BEST explanation for why a catalyst speeds up a reaction?
A) The catalyst increases the concentration of the products
B) The catalyst decreases the total pressure in the container.
C) The catalyst raises the temperature of the reaction mixture.
D) The catalyst lowers the activation energy required for the reaction to occur.
E) The catalyst increases the probability that a collision will occur by taking up space in the container.
D is clearly the correct answer. In a sense, activation energy is related to temperature and at higher temps, molecules move faster and therefore have more frequent collisions. Catalysts lower the activation energy by bringing substrates together.
The BEST explanation for why a catalyst speeds up a reaction is option D) The catalyst lowers the activation energy required for the reaction to occur.
To understand this explanation, let's break it down further:
A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It does this by providing an alternative reaction pathway with a lower activation energy.
Activation energy is the energy required for a chemical reaction to start. It acts as a barrier that reactant molecules must overcome to form products. By lowering the activation energy, a catalyst makes it easier for reactant molecules to reach the transition state, which is the point where the reaction occurs.
When a catalyst is present, it provides an alternative reaction pathway that has a lower activation energy compared to the uncatalyzed reaction. This allows a greater proportion of reactant molecules to have sufficient energy to overcome the lower energy barrier and proceed to form products.
Therefore, the catalyst speeds up the reaction by lowering the activation energy, allowing more reactant molecules to successfully undergo the reaction and form products.