Final answer:
The true statement about reaction rates among the options presented is that changing the surface area of reactants affects the reaction rate. Additionally, catalysts speed up reactions, and both the concentration of reactants and temperature can also impact the speed of a reaction.
Step-by-step explanation:
The statement about reaction rates that is true is that changing the surface area affects the reaction rate. When the surface area of reactants is increased, there is a larger area for reactants to come into contact with each other, promoting more frequent collisions and resulting in an increased reaction rate. On the other hand, a catalyst is a substance that speeds up the rate of a chemical reaction by providing an alternative pathway with a lower activation energy, without being consumed by the reaction itself.
It is also important to note that changing the amount of reactants does affect the reaction rate because increasing the concentration of reactants will generally increase the reaction rate due to a higher frequency of collisions. Similarly, changing the temperature can indeed speed up a reaction rate. As temperature increases, particle movement becomes more vigorous, leading to more collisions and therefore a higher chance of successful interactions that can lead to the formation of products.