Answer:
it is a chemical reaction in which one element replaces an/other element in a compound. It can be represented generically as: A + B-C → A-C + B This will most often occur if A is more reactive than B, thus giving a more stable product.
HCH bond angle is ~110 degrees.
The frequency of a wave represents B. the number of wave cycles that pass through a specific point within a given time.
The distance between two consecutive crests and the length of a wave are the <em>wavelength</em>.
The distance between the highest and lowest points of a wave is <em>twice the amplitude</em>.