Refer to the graphs to compare the rate of this reaction with and without a catalyst.
which best describes the role of a catalyst in the rate of a reaction?
a. catalysts increase the activation energy required for a reaction, thus slowing the reaction rate.
b. catalysts increase the activation energy required for a reaction, thus increasing the reaction rate.
c. catalysts lower the activation energy required for a reaction, thus slowing the reaction rate.
d. catalysts lower the activation energy required for a reaction, thus increasing the reaction rate.

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s.part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.