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.
The answer is D :D
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 why this is the case, it is important to first understand what a catalyst is. A catalyst is a substance that increases the rate of a chemical reaction by providing an alternative reaction pathway with a lower activation energy. Activation energy is the minimum amount of energy required for a chemical reaction to occur.
A catalyst works by providing an alternative reaction pathway that requires less energy to be activated. By lowering the activation energy, more particles in the reaction mixture can overcome this energy barrier, allowing the reaction to proceed at a faster rate. This is why a catalyst can increase the rate of a reaction without being consumed in the process.
Option A is incorrect because a catalyst does not increase the concentration of the products. It does not affect the equilibrium concentrations of reactants and products.
Option B is incorrect because a catalyst does not affect the total pressure in the container. Pressure is determined by the number of gas molecules present, not by the presence of a catalyst.
Option C is incorrect because a catalyst does not raise the temperature of the reaction mixture. While temperature can affect the rate of a reaction, a catalyst is not responsible for heating up the reaction.
Option E is incorrect because a catalyst does not increase the probability of a collision by taking up space in the container. The role of a catalyst is to provide an alternative reaction pathway, not to physically obstruct or restrict the reactant molecules.