Making bonds/breaking bonds and energetics

In summary, the conversation discusses the concept of whether making bonds and breaking bonds are exothermic or endothermic. The explanation involves the Leonard-Jones potential and the energy of bonded and non-bonded atoms. It is clarified that breaking a bond is endothermic, similar to breaking a window with a hammer.
  • #1
member 392791
Hello,

I have never been able to keep straight in my head if making bonds and breaking bonds are exothermic or endothermic. Is there any way that someone can explain why which is which in a way that is understandable because I'm tired of constantly having to re memorize it.
 
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  • #2
I always think of it in terms of the Leonard-Jones potential, which describes the energy to two atoms as a function of the distance between them:
=Figure_B.jpg


The energy of bonded atoms is the energy where the LJ potential is at a minimum, whereas non-bonded atoms are separated by large distances and their energies are found all the way to the far right of the curve. What happens to the energy of two unbonded atoms as they approach each other? Will they need to release energy to the surroundings (because they themselves are decreasing in energy) or do they need to gain energy from the surroundings? For two bonded atoms to become unbonded, will they need to gain energy from their surroundings or release energy to their surroundings?
 
  • #3
Ok just read something that seemed easy to remember...so it's like breaking a window with a hammer. When you break a window, the energy is transferred from the hammer to the window, thus breaking a windows absorbs energy, so breaking a bond absorbs energy, thus endothermic.
 

1. How does making or breaking bonds affect the energy of a system?

Making and breaking bonds involve the transfer of energy between atoms or molecules. When bonds are made, energy is released, resulting in a decrease in the overall energy of the system. On the other hand, breaking bonds requires an input of energy, causing an increase in the system's energy.

2. How is the strength of a bond related to its energy?

The strength of a bond is directly related to its energy. The stronger the bond, the higher the amount of energy required to break it. This is because stronger bonds have lower potential energy and are more stable than weaker bonds.

3. What factors influence the energy of a bond?

The energy of a bond is influenced by two main factors: the type of atoms involved and the distance between them. Different types of atoms have different bond strengths, and the closer the atoms are to each other, the stronger the bond will be.

4. How does bond formation or breaking relate to exothermic and endothermic reactions?

Bond formation is an exothermic process, which means it releases heat and energy to the surroundings. In contrast, bond breaking is an endothermic process, requiring an input of energy. This relationship is why exothermic reactions are often used to generate heat, while endothermic reactions are used to absorb heat.

5. Can bond energies be measured experimentally?

Yes, bond energies can be measured experimentally using techniques such as calorimetry and spectroscopy. These methods involve measuring the energy changes associated with bond formation or breaking in a controlled environment, providing valuable information about the strength and stability of different types of bonds.

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