Is air a compound mixture or a element. compound
Doppler effect is the compression or extension of a sound wave, which causes a change in its wavelength / frequency (and so its sound).
Explanation: It is defined as the effect produced by a moving source of waves in which there is an upward shift in frequency for observers, the source is moving towards and downward shift of frequency from which the source is moving away. used to tell if an object in space is moving toward or away from us.
According to the illustration, the vanadium (V) oxide would be a catalyst.
<h3>What are catalysts?</h3>
Catalysts are substances that are utilized in reactions that are not themselves consumed in reactions but only speed up the rate of the reactions.
Catalysts speed up the rate of reactions by lowering the activation energy of the reactants.
Sulfur dioxide reacts with oxygen to produce sulfur trioxide. The vanadium (v) oxide is not consumed in the reaction. Thus it only serves as a catalyst.
More on catalysts can be found here: brainly.com/question/12260131
#SPJ1