Question

What is the energy per mole of photons with a wavelength of 307.1 nm? (c=3.00×108 m/s, h=6.63×10-34 J·s, NA=6.02×1023mol-1)

Answer 1

Ephoton= hc/wavelength

Step by step:

1. Convert the wavelength of 570nm to m:

10-9m= 1 nm,

so: 307.1nm * (10-9m) = 3.071E-7 m

2. Ephoton= hc/wavelength

Ephoton= (6.63E-34 * 3.E8)/3.071E-7 m

Ephoton= 6.48E-19 J

3. Finally, I convert to kJ:

Ephoton= 6.48E-19J/1000J = 6.48E-22 kJ

One mole of any substance contains this many [6.022 × 10E23] units
the energy per mole of photons with a wavelength of 307.1 nm = (6.48E-22 kJ)(6.02 × 10E23) = 390.1 kJ

the energy per mole of photons with a wavelength of 307.1 nm = 390.1 kJ