Question

For certain photochemical reactions, multiple photons are required per molecule to initiate the reaction. How many photons is needed to initiate a photochemical reaction that requires 6.8 x 10⁻²⁰ kJ energy per molecule when the light has a wavelength of 312 nm?

Answer 1

To determine how many photons are needed for a photochemical reaction with a given energy requirement per molecule and a specific wavelength of light, the energy of a single photon must be calculated using Planck's equation, and then this value is used to calculate the total number of photons necessary.

Step-by-step explanation:

The question requires calculating the number of photons needed to initiate a photochemical reaction that requires 6.8 x 10⁻²⁰ kJ energy per molecule with light of a wavelength of 312 nm. To find this, we need to first determine the energy of a single photon with a wavelength of 312 nm.

Using the formula for the energy of a photon, E = hc/λ, where h is Planck's constant (6.63 x 10⁻³⁴ J·s), c is the speed of light (3.00 x 10⁸ m/s), and λ is the wavelength. After calculating the energy per photon, we divide the required energy per molecule (6.8 x 10⁻²⁰ kJ) by this energy to find the number of photons required.