Wavelength for breaking a bond

In summary, the question asks to calculate the maximum wavelength of electromagnetic radiation that can break the weakest bond in AsClF42-. The given bond energies for As-As, F-F, and Cl-Cl are 180 kJ/mol, 160 kJ/mol, and 240 kJ/mol respectively. However, the literature values for As-As bond energy is around 380 kJ/mol, suggesting that the given bond energies may be dummy values.
  • #1
guiromero
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Mentor's Note: Post moved to homework forum from chemistry forum.

Hello,

I have a doubt in anexercise from MIT:
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Calculate the maximum wavelength, λ, of electromagnetic radiation capable of breaking the weakest bond in of AsClF42-.

Bond Energies (kJ/mol): As-As 180; F-F 160; Cl-Cl 240.

Enter the numerical value of λ in meters:
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This molecule has As-Cl and Cl-F bonds, but I don't know how to calculate these bonds energies from the given values. Does anynone know how to do that?

Thanks a lot.
 
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  • #2
Could there be a previous question with some additional information? Because the question cannot be answered with the data given.
 
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Likes jim mcnamara
  • #3
There's a previous question simliar to that, but I can't find the statement. However, I know the formulas are:

Energy (J) = [BE * 1000] / Avogador's number

Where:
BE: Bond energy (KJ/mol)

Wavelength (m) = (h * c) / Energy

Where:
h: Plancks' constant (m^2 * kg * s^-1)
c: Speed of light (m * s^-1)

In this case, BE should be the smallest value among the bond energies found in the molecule. I find that this molecule only has two types of bonds: As-Cl and Cl-F. However, I don't know how to calculate any of these bonds' energies from the data given (Bond energies of As-As 180; F-F 160; Cl-Cl 240).

I thought of taking the mean value of two given bond energies, for example :

Bond energy of As-Cl = (Bond energy of As-As + Bond energy of Cl-Cl) / 2

But this didn't work. Do you know how to do that?
 
  • #4
Are the given bond energies dummy values? Because literature says As-As is around 380 kJ/mol.[1][2]
 
  • #5
Mayhem said:
Are the given bond energies dummy values? Because literature says As-As is around 380 kJ/mol.[1][2]
As they are different from the literature values, I suppose they are dummy. Thanks for your help.
 

Related to Wavelength for breaking a bond

What is the wavelength required to break a chemical bond?

The wavelength required to break a chemical bond depends on the bond's dissociation energy. The energy of a photon needed to break a bond can be calculated using the formula \(E = \frac{hc}{\lambda}\), where \(E\) is the bond dissociation energy, \(h\) is Planck's constant, \(c\) is the speed of light, and \(\lambda\) is the wavelength. By rearranging the formula, \(\lambda = \frac{hc}{E}\), you can find the wavelength.

How do you calculate the wavelength from bond dissociation energy?

To calculate the wavelength from bond dissociation energy, use the formula \(\lambda = \frac{hc}{E}\). Here, \(h\) (Planck's constant) is approximately \(6.626 \times 10^{-34}\) Js, \(c\) (speed of light) is approximately \(3 \times 10^8\) m/s, and \(E\) is the bond dissociation energy in joules. Plug these values into the formula to find the wavelength in meters.

What role does bond dissociation energy play in determining the wavelength?

Bond dissociation energy is the energy required to break a bond. It directly determines the wavelength of light needed to provide that energy. Higher bond dissociation energies require photons with higher energies and, therefore, shorter wavelengths. Conversely, lower bond dissociation energies require photons with lower energies and longer wavelengths.

Can visible light break chemical bonds?

Visible light can break chemical bonds if the bond dissociation energy corresponds to the energy of visible light photons. However, many chemical bonds require ultraviolet (UV) light, which has higher energy photons, to be broken. Visible light typically ranges from 400 to 700 nm in wavelength, and not all bonds can be broken by this range of energy.

Why are ultraviolet (UV) wavelengths often used to break chemical bonds?

Ultraviolet (UV) wavelengths are often used to break chemical bonds because they have higher energy photons compared to visible light. Many chemical bonds have dissociation energies that require the higher energy provided by UV light to be broken. UV light typically ranges from 10 to 400 nm in wavelength, which corresponds to higher photon energies suitable for breaking stronger chemical bonds.

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