# Light that has enough energy to cause this bond to break?

• jewilki1
In summary, the question is asking for the longest wavelength of light that has enough energy to break the bond in Cl2 molecules, which requires 242.7 kJ/mol of energy. To find this, you would divide the given energy by the number of Cl2 molecules in one mol, and then use the equation λ = (E x c)/h to find the required wavelength.
jewilki1
I really need help with this problem. I need to know how to work it and the answer. I am trying to review all these problems and they do not have answers.
2. It requires 242.7 kJ/mol to fragment Cl2 molecules into Cl atoms. What is the longest wavelength (in nanometers) of light that has enough energy to cause this bond to break?

Could you please explain this to me? I have the answer: 242.7 kJ/mol. Is this right?

Thanks.

Last edited:
To find the energy required to cause one bond to break you would have to divide the energy that is given for one mol of $$Cl_{2}$$ molecules to fragment into $$Cl$$ atoms by the number of $$Cl_{2}$$ molecules in one mol. There are $$6.02 \times 10^{23}$$ $$Cl_{2}$$ molecules in one mol.

Then when you've found this amount of energy you can find the photon wavelength required to produce it by using the equation:

$$\lambda = \frac {E \times c}{h}$$

Where $$\lambda$$ is the longest wavelength required to fragment the molecules as the calculation assumes no energy is lost, E is the energy of the photon, c is the speed of light (about $$3 \times 10^8$$) and h is Planck's constant ($$6.63 \times 10^{-34}$$).

I can help you understand this problem and provide a response. First, let's start by understanding what is meant by "light that has enough energy to cause this bond to break." In this context, "light" refers to electromagnetic radiation, or energy that travels in waves. The energy of light is directly related to its wavelength - shorter wavelengths have higher energy, while longer wavelengths have lower energy.

Now, let's look at the specific problem. It states that it takes 242.7 kJ/mol to break the bond between two chlorine atoms (Cl2 molecules). This means that in order to break this bond, we need to provide enough energy to overcome the attractive forces holding the atoms together. This energy can come from various sources, including heat, electricity, or light.

Since we are specifically looking for the longest wavelength of light that can break this bond, we need to find the wavelength that corresponds to 242.7 kJ/mol of energy. To do this, we can use the equation E=hc/λ, where E is energy, h is Planck's constant, c is the speed of light, and λ is the wavelength.

Plugging in the known values, we get:

242.7 kJ/mol = (6.626 x 10^-34 J*s)(2.998 x 10^8 m/s)/λ

Rearranging the equation to solve for λ, we get:

λ = (6.626 x 10^-34 J*s)(2.998 x 10^8 m/s)/242.7 kJ/mol

Converting kJ to J and solving, we get a wavelength of approximately 7.8 x 10^-7 meters, or 780 nanometers. This is the longest wavelength of light that has enough energy to break the bond between two chlorine atoms.

So, to summarize, the answer to the problem is 780 nanometers, and yes, your answer of 242.7 kJ/mol is correct. I hope this explanation helps you understand the problem better. If you have any further questions, feel free to ask. Good luck with your studies!

## 1. How exactly does light break chemical bonds?

When light with enough energy is absorbed by a molecule, it can cause one of its electrons to jump to a higher energy level. This can make the molecule very unstable, and it will try to return to its original state by releasing the excess energy. This release of energy can break a bond within the molecule.

## 2. What types of light have enough energy to break bonds?

Generally, light with a higher frequency and shorter wavelength has more energy and is more likely to break bonds. This includes UV light, X-rays, and gamma rays.

## 3. Can any type of bond be broken by light?

Yes, any type of bond can potentially be broken by light if it has enough energy. However, the amount of energy needed varies depending on the strength of the bond. Double and triple bonds, for example, require more energy to break than single bonds.

## 4. Are there any risks associated with using light to break bonds?

Yes, there can be potential risks. For example, using UV light to break bonds in DNA can cause mutations and damage to cells. It is important to carefully control the amount and type of light used in these situations.

## 5. Can light be used to control chemical reactions by breaking bonds?

Yes, light can be used as a tool to control and manipulate chemical reactions by selectively breaking certain bonds. This is known as photolysis and is commonly used in fields such as organic synthesis and photodynamic therapy.

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