What is the change in enthalpy (ΔH) for a chemical reaction? How is ΔH different from ΔE?

Solution: The distance between two adjacent crests or troughs is called wavelength. It is denoted by the greek letter lambda() and is generally expressed in terms of Angstrom units(A ) [1 A = 10 -10m] On the other hand, the number of waves which pass through a given point in one second is known as the frequency. It is denoted by the greek letter nu() and is generally expressed in -1 terms of Hertz(Hz) [1 Hz = 1 sec ] If c is the velocity of light, the the relation between wavelength, frequency and velocity of light is given by: c = x ------(1) Step1: a) Given, wavelength of the radiation = 0.86 nm -9 -9 = 0.86 x 10 m [1 nm = 10 m] -10 = 8.6 x 10 m Velocity of light, c = 3 x 10 m/sec8 Substituting the values in equation (1), we get, 8 -10 frequency() = ( 3 x 10 m/sec) / (8.6 x 10 m) = 0.349 x 10 sec . -1 = 3.49 x 10 sec . -1 17 -1 Thus, frequency of the radiation is...