Multiple Choice
What total energy (in kJ) is contained in 1.0 mol of photons, all with a frequency of 2.75 × 10^14 Hz?
9. Quantum Mechanics
The Energy of Light
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What is the energy in kJ/mol of infrared radiation with a wavelength of 1.51 × 10⁻⁶ m?
A
79.1 kJ/mol
B
104.6 kJ/mol
C
25.7 kJ/mol
D
52.3 kJ/mol
Verified step by step guidance1
Start by understanding the relationship between energy and wavelength. The energy of a photon can be calculated using the formula: , where is Planck's constant (), is the speed of light (), and is the wavelength.
Substitute the given wavelength into the formula. Here, is . Plug this value into the equation: .
Calculate the energy per photon using the substituted values. This will give you the energy in joules per photon. Remember that the units of will be in joules since you are using SI units.
Convert the energy from joules per photon to kilojoules per mole. Use Avogadro's number ( molecules/mol) to find the energy per mole: .
Compare the calculated energy in kJ/mol with the given options to determine the correct answer. The calculated value should match one of the provided choices.
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