Answer the following question given this paragraph: 

Mole-mole calculations are not the only type of calculations that can be performed using balanced chemical equations. Recall that the molar mass can be determined from a chemical formula and used as a conversion factor. We can add that conversion factor as another step in a calculation to make a molemass calculation, where we start with a given number of moles of a substance and calculate the mass of another substance involved in the chemical equation, or vice versa. For example, suppose we have the balanced chemical equation.


Q: What effect, related to weather forecasting, occurs not only for sound but for any wave when there is relative motion between the observer and the source?


A:
doppler