Negative energies?  [ENDORSED]

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Emerald Wong 1B
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Negative energies?

Postby Emerald Wong 1B » Mon Nov 09, 2020 12:45 pm

I am still a little confused on the explanation for why the energies where negative when Dr. Lavelle was talking about the interactions between ions and molecules. He said it was because energy is released? I am not completely sure; I thought the interaction between the ions as they come together would require energy, which makes it negative. Can someone clarify?

Akshata Kapadne 2K
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Re: Negative energies?

Postby Akshata Kapadne 2K » Mon Nov 09, 2020 12:48 pm

When bonds form between molecules, they release energy, which is why Lavelle showed the energy as negative. Conversely, when bonds break, they require energy.

Ria Nawathe 1C
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Re: Negative energies?

Postby Ria Nawathe 1C » Mon Nov 09, 2020 12:56 pm

In terms of thermodynamics, if you think about the molecule/compound as a system, anything that increases the energy of the system, for example putting in energy to break bonds, makes delta E positive. When energy is released, delta E is negative. The intermolecular/interionic interactions have negative energy because they are favorable interactions that lower the energy of the system. For example, the electrostatic attraction between Na+ and Cl- makes it more energetically favorable for them to form an ion-ion interaction (ionic bond); NaCl is more stable than Na+ and Cl- separately, which lowers the energy of the system. Therefore, the energies are negative. Hope this helps!

Liam Bertrand 3
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Re: Negative energies?

Postby Liam Bertrand 3 » Mon Nov 09, 2020 1:32 pm

When ions form a bond and come together it releases energy, it then requires energy to break that bond again.

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Re: Negative energies?

Postby Lucy_Balish_3G » Mon Nov 09, 2020 1:46 pm

Negative energies imply that energy is given off by what is taking place. In this case, the more negative energy forces for ion-ion attractions and hydrogen bonds are more favorable and give off more energy than dipole-dipole and dipole induced-dipole. The reverse is true that a greater energy must be input to break an ion-ion and hydrogen bond than dipole-dipole or dipole induced-dipoles. But since we are concerned with the formations of these bonds and attractions, the energy will be negative because it is an output of the attractions.

Site Admin
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Re: Negative energies?  [ENDORSED]

Postby Chem_Admin » Mon Nov 09, 2020 2:16 pm

I will go through this in my 3pm discussion section today.

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Re: Negative energies?

Postby Joseph_Armani_3K » Mon Nov 09, 2020 3:48 pm

When ions interact, it's because the resulting compound would be more stable than if they were individual ions. That's why when they interact and form an ionic bond, they release energy.

Nandhini Ekambaram 1L
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Re: Negative energies?

Postby Nandhini Ekambaram 1L » Mon Nov 09, 2020 4:07 pm

During Dr. Lavelle's OH, he also mentioned that having negative energy is favorable since it has low energy.

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