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Freedom physics
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Please may someone explain this sentence? 🙂: "the electrostatic forces between atoms and molecules give the electrostatic potential energy a negative value. The negative simply means that energy must be supplied to break the atomic or molecular bonds"
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thatmememachine
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My brain is tired
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Eimmanuel
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(Original post by Freedom physics)
Please may someone explain this sentence? 🙂: "the electrostatic forces between atoms and molecules give the electrostatic potential energy a negative value. The negative simply means that energy must be supplied to break the atomic or molecular bonds"

I am not sure what is that you want people to explain.
One confusing thing about the first sentence “the electrostatic forces between atoms and molecules” is that are you referring to
(1) forces of attraction between two atoms or more
(2) forces of attraction between two molecules or more
(3) forces of attraction between one molecule and one atom

Although the nature of the force of attraction for the above 3 examples is similar, it would be better that you make clear what do expect people to explain.

You can borrow the concept of chemical bonding from chemistry. Take for example monoatomic Neon (one of the noble gas element) which does not form chemical bond such as covalent bond but Neon can still exist as solid, liquid. It is because of the “intermolecular” force. This “intermolecular” force is sometimes called van der Waals’ forces or London dispersion force or temporary dipole–induced dipole forces or dipole-induced dipole interaction.

The nature of the “intermolecular” force between Neon atoms that keep them together in liquid state is electric force or electrostatic force. The electric interactions of the atoms mean that the system of atoms have electric potential energy and the value of the electric potential energy of the atoms is negative because by convention, the zero electric potential energy is taken be when the atoms are infinite apart and the attractive nature of the electric force between atoms.

To break the “intermolecular” force between Neon atoms, we need to supply energy or heat to the system that is to change its state.

This is similar to the gravitational potential energy of a satellite-Earth system – the satellite is orbiting around the Earth. The gravitational potential energy of a satellite-Earth system is also negative. For the satellite to escape from the attraction of the Earth, we need to give energy to the satellite to move at a speed greater than the escape speed.
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Freedom physics
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(Original post by Eimmanuel)
I am not sure what is that you want people to explain.
One confusing thing about the first sentence “the electrostatic forces between atoms and molecules” is that are you referring to
(1) forces of attraction between two atoms or more
(2) forces of attraction between two molecules or more
(3) forces of attraction between one molecule and one atom

Although the nature of the force of attraction for the above 3 examples is similar, it would be better that you make clear what do expect people to explain.

You can borrow the concept of chemical bonding from chemistry. Take for example monoatomic Neon (one of the noble gas element) which does not form chemical bond such as covalent bond but Neon can still exist as solid, liquid. It is because of the “intermolecular” force. This “intermolecular” force is sometimes called van der Waals’ forces or London dispersion force or temporary dipole–induced dipole forces or dipole-induced dipole interaction.

The nature of the “intermolecular” force between Neon atoms that keep them together in liquid state is electric force or electrostatic force. The electric interactions of the atoms mean that the system of atoms have electric potential energy and the value of the electric potential energy of the atoms is negative because by convention, the zero electric potential energy is taken be when the atoms are infinite apart and the attractive nature of the electric force between atoms.

To break the “intermolecular” force between Neon atoms, we need to supply energy or heat to the system that is to change its state.

This is similar to the gravitational potential energy of a satellite-Earth system – the satellite is orbiting around the Earth. The gravitational potential energy of a satellite-Earth system is also negative. For the satellite to escape from the attraction of the Earth, we need to give energy to the satellite to move at a speed greater than the escape speed.
Please, may you explain the negative part? And thank you for all of the explanation
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spidle
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It is simply saying that when you see a potential energy value, it will have a negative sign in front of it. Why? Because that amount of energy is needed to enter the system and break the bonds. So if the potential value was -500J you would need 500J of energy to break the bonds.
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Eimmanuel
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(Original post by Freedom physics)
Please, may you explain the negative part? And thank you for all of the explanation
I thought I explain about it already.
(Original post by Eimmanuel)
... The nature of the “intermolecular” force between Neon atoms that keep them together in liquid state is electric force or electrostatic force. The electric interactions of the atoms mean that the system of Neon atoms have electric potential energy and the value of the electric potential energy of the system of Neon atoms is negative because by convention, the zero electric potential energy is taken be when the atoms are infinite apart and the attractive nature of the electric force between atoms.

To break the “intermolecular” force between Neon atoms, we need to supply energy or heat to the system that is to change its state.

.....
Or what is unclear?
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Freedom physics
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(Original post by Eimmanuel)
I thought I explain about it already.


Or what is unclear?
I don't know how the magnitude of the intermolecular forces can have negative values, do they have negative values because the forces repulse other atoms?
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Eimmanuel
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(Original post by Freedom physics)
I don't know how the magnitude of the intermolecular forces can have negative values, do they have negative values because the forces repulse other atoms?
In physics, magnitude is always positive. Please be more clear on what you want to say.

Force is a vector quantity. We tend to denote attractive force to be negative such as gravitational force and repulsive force to be positive such as repulsion between two similar charged particles.

You can try to draw the analogy between gravitational force and “intermolecular” force. But throw away the analogy after you understand the concept of “intermolecular” force.

You may want to study the reference(s) in the following links.

https://opentextbc.ca/chemistry/chap...ecular-forces/

https://chem.libretexts.org/Core/Phy...ones_Potential
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Freedom physics
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(Original post by Eimmanuel)
In physics, magnitude is always positive. Please be more clear on what you want to say.

Force is a vector quantity. We tend to denote attractive force to be negative such as gravitational force and repulsive force to be positive such as repulsion between two similar charged particles.

You can try to draw the analogy between gravitational force and “intermolecular” force. But throw away the analogy after you understand the concept of “intermolecular” force.

You may want to study the reference(s) in the following links.

https://opentextbc.ca/chemistry/chap...ecular-forces/

https://chem.libretexts.org/Core/Phy...ones_Potential
Thank you! I am aiming to be clearer! Thanks for all of the help you're being very helpful!! 😄
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