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The green light associated with the aurora borealis is emitted by high energy oxygen atoms at 557.7 nm.

(a) What is the wavenumber value of this light (measured in reciprocal centimetres)?

(b) Determine the energy in joules of a photon emitted by an excited oxygen atom.

(c) Determine the energy in kilojoules of a mole of such photons.

1 Answer

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Final answer:

The wavenumber value of the green light associated with the aurora borealis is 0.0179 cm^-1. The energy of a photon emitted by an excited oxygen atom is 1.121 x 10^-19 J. The energy in kilojoules of a mole of such photons is 6.7444 x 10^4 kJ/mol.

Step-by-step explanation:

(a) The wavenumber value can be calculated using the formula:
Wavenumber (cm-1) = 1 / Wavelength (cm)
Since the wavelength of the green light is 557.7 nm, we need to convert it to cm by dividing it by 10:
Wavelength (cm) = 557.7 nm / 10 = 55.77 cm
Now we can calculate the wavenumber:
Wavenumber (cm-1) = 1 / 55.77 cm = 0.0179 cm-1

(b) The energy of a photon can be calculated using the formula:
Energy (J) = Planck's constant (6.626 x 10-34 J·s) x Speed of light (3.00 x 108 m/s) / Wavelength (m)
First, we need to convert the wavelength from nm to m by dividing it by 109:
Wavelength (m) = 557.7 nm / 109 = 5.577 x 10-7 m
Now we can calculate the energy:
Energy (J) = (6.626 x 10-34 J·s) x (3.00 x 108 m/s) / (5.577 x 10-7 m) = 1.121 x 10-19 J

(c) To determine the energy in kilojoules of a mole of such photons, we need to multiply the energy of one photon by Avogadro's number (6.022 x 1023 mol-1):
Energy (kJ/mol) = (1.121 x 10-19 J) x (6.022 x 1023 mol-1) / 1000 = 6.7444 x 104 kJ/mol

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